Skin Tumors — MCQs

Q: What is the dermatological sign associated with carcinoma of the stomach?

Acanthosis Nigrans. **Explanation:** **Acanthosis Nigricans (AN)** is the correct answer. While AN is most commonly associated with insulin resistance and obesity (Benign AN), its sudden, severe, and widespread onset in an older individual—often involving the palms (tripe palms) and mucous membranes—is a classic **paraneoplastic syndrome**. **Malignant Acanthosis Nigricans** is most frequently associated with **adenocarcinomas of the gastrointestinal tract**, with **stomach cancer** being the most common (approx. 50-60% of cases). It is thought to be mediated by tumor-secreted growth factors like Transforming Growth Factor-alpha (TGF-α) acting on epidermal EGF receptors. **Analysis of Incorrect Options:** * **A. Palmoplantar Keratoderma (PPK):** While acquired PPK can be paraneoplastic (Howel-Evans Syndrome), it is specifically linked to **Esophageal carcinoma**, not primarily the stomach. * **B. Acquired Ichthyosis:** This sudden onset of "fish-like" scaling in adulthood is most strongly associated with **lymphomas** (specifically Hodgkin’s Lymphoma), rather than gastric malignancies. * **D. Acrokeratosis Paraneoplastica (Bazex Syndrome):** This presents with psoriasiform plaques on acral sites (ears, nose, fingers). It is highly specific for squamous cell carcinomas of the **upper aerodigestive tract** (head, neck, and esophagus). **High-Yield Clinical Pearls for NEET-PG:** * **Tripe Palms:** When AN affects the palms, appearing velvety and rugose, it is 90% predictive of internal malignancy. If seen with AN, think **Stomach CA**; if seen alone, think **Lung CA**. * **Leser-Trélat Sign:** The sudden eruption of multiple Seborrheic Keratoses is another major cutaneous marker for **Gastric Adenocarcinoma**. * **Sister Mary Joseph Nodule:** A palpable nodule at the umbilicus representing metastasis from a pelvic or abdominal malignancy (most commonly Stomach CA).

Q: Which of the following conditions shows susceptibility to squamous cell carcinoma in the skin?

All the above. **Explanation:** Squamous Cell Carcinoma (SCC) of the skin is a malignant tumor of epidermal keratinocytes. Its development is often preceded by precancerous lesions or genetic conditions that impair the skin's ability to repair DNA damage or control viral oncogenesis. * **Epidermodysplasia Verruciformis (EV):** This is a rare genetic disorder characterized by an abnormal susceptibility to **Human Papillomaviruses (HPV)**, particularly types 5 and 8. Patients develop chronic wart-like lesions that have a high propensity (30-60%) for transforming into SCC, especially on sun-exposed areas. * **Actinic Keratosis (AK):** Also known as solar keratosis, these are considered **premalignant** lesions. They represent the earliest clinical stage of SCC in situ. Histologically, they show keratinocyte atypia; if left untreated, approximately 1-10% progress to invasive SCC. * **Xeroderma Pigmentosum (XP):** This is an autosomal recessive disorder caused by a defect in **Nucleotide Excision Repair (NER)**. Patients cannot repair DNA damage caused by UV radiation, leading to a 10,000-fold increased risk of developing skin cancers, including SCC, Basal Cell Carcinoma (BCC), and Melanoma at a very young age. Since all three conditions are well-documented precursors or risk factors for SCC, **Option D** is the correct answer. **High-Yield Clinical Pearls for NEET-PG:** * **Marjolin’s Ulcer:** SCC arising in chronic scars, non-healing ulcers, or burn sites. It is more aggressive than UV-induced SCC. * **Bowen’s Disease:** A clinical term for SCC in situ (full-thickness atypia without basement membrane invasion). * **Arsenic Exposure:** A systemic risk factor that typically leads to multiple SCCs on the palms and soles. * **Most common site for SCC:** Lower lip (whereas BCC is more common on the upper lip).

Q: Which of the following lesions shows characteristic anagen, catagen, and telogen phases?

Keratoacanthoma. **Explanation:** **Keratoacanthoma (KA)** is a common, rapidly growing epithelial tumor that clinically and histologically resembles Squamous Cell Carcinoma (SCC). The hallmark of KA is its unique life cycle, which mimics the **hair follicle cycle**. It originates from the follicular infundibulum and progresses through three distinct stages: 1. **Proliferative phase (Anagen-like):** Rapid growth over 4–6 weeks, forming a dome-shaped nodule with a central keratinous plug. 2. **Stationary phase (Catagen-like):** Growth ceases, and the lesion stabilizes. 3. **Involutional phase (Telogen-like):** Spontaneous regression occurs over weeks to months, often leaving a puckered scar. **Analysis of Incorrect Options:** * **Basal Cell Carcinoma (BCC):** The most common skin cancer. It is characterized by slow growth, "pearly" borders, and telangiectasia. It does not undergo spontaneous regression or follow a follicular cycle. * **Leukoplakia:** A clinical term for a white patch on the mucosa that cannot be characterized as any other disease. It is a premalignant condition, not a follicular-derived tumor. * **Squamous Cell Carcinoma (SCC):** While KA is often considered a well-differentiated variant of SCC, true SCC is characterized by progressive, uncontrolled growth and invasion without a programmed involutional phase. **High-Yield NEET-PG Pearls:** * **Clinical Appearance:** "Volcano-like" appearance (dome-shaped with a central keratin plug). * **Histology:** Shows a central keratin-filled crater with "lips" or "buttresses" of overhanging epithelium. * **Syndrome Association:** Multiple keratoacanthomas are seen in **Muir-Torre Syndrome** (associated with internal malignancies) and **Grzybowski type** (generalized eruptive KAs). * **Management:** Despite spontaneous regression, surgical excision is usually recommended because it is difficult to distinguish KA from aggressive SCC.

Q: A patient presents with multiple, pearly papules on the face. Biopsy reveals a malignant tumor. Which of the following microscopic features would most likely be observed?

Palisading nuclei. **Explanation:** The clinical presentation of **pearly papules** on the face, often with telangiectasia, is the classic description of **Basal Cell Carcinoma (BCC)**, the most common skin cancer. **Why the correct answer is right:** The hallmark histopathological feature of BCC is the presence of nests or islands of basaloid cells (cells with large, dark nuclei and scant cytoplasm). At the periphery of these nests, the nuclei align themselves in a parallel, fence-like arrangement known as **peripheral palisading**. Additionally, a characteristic "retraction artifact" (clefting) is often seen between the tumor nests and the surrounding stroma. **Why the incorrect options are wrong:** * **A. Cytoplasmic viral inclusions:** These are characteristic of viral infections like Molluscum Contagiosum (Henderson-Patterson bodies) or HPV (koilocytes), not malignant tumors like BCC. * **B. Keratin:** While BCC can occasionally show focal keratinization (Basosquamous variant), **Keratin pearls** are the pathognomonic feature of **Squamous Cell Carcinoma (SCC)**. * **C. Melanin:** While "Pigmented BCC" exists, melanin is the defining feature of **Melanoma**. In a general question about pearly papules, palisading is the more specific diagnostic marker for BCC. **High-Yield NEET-PG Pearls:** * **Most common site:** Upper 2/3rd of the face (above the line joining the earlobe to the angle of the mouth). * **Risk Factor:** Chronic UV exposure; also associated with **Gorlin Syndrome** (PTCH gene mutation). * **Behavior:** Locally invasive ("Rodent ulcer") but rarely metastasizes. * **Treatment of choice:** Surgical excision or Mohs Micrographic Surgery (for high-risk areas).

Q: What is true regarding Kaposi's sarcoma?

All of the above are true. **Explanation:** Kaposi’s Sarcoma (KS) is a multicentric angioproliferative tumor derived from vascular and lymphatic endothelial cells. It is uniquely associated with **Human Herpesvirus 8 (HHV-8)**, also known as Kaposi Sarcoma-associated Herpesvirus (KSHV). * **Option A (CD4 Count):** While KS is an AIDS-defining illness typically seen when CD4 counts are <200 cells/mm³, it can occur in individuals with **normal CD4 counts**. This is particularly true in the "Classic (Sporadic)" variant seen in elderly Mediterranean men and the "Endemic (African)" variant, where HIV infection is not a prerequisite. * **Option B (Etiology):** HHV-8 is the definitive causative agent across all four clinical types (Classic, Endemic, Iatrogenic/Transplant-related, and AIDS-associated). The virus induces spindle cell proliferation and angiogenesis. * **Option C (Koebner’s Phenomenon):** KS is one of the few neoplastic conditions that can exhibit the **Pseudo-Koebner phenomenon**, where new lesions develop at sites of trauma or previous injury. **Clinical Pearls for NEET-PG:** * **Histopathology:** Characterized by **spindle-shaped cells**, slit-like vascular spaces containing extravasated RBCs, and **hyaline droplets**. * **Clinical Presentation:** Presents as palpable, non-blanching, violaceous (purplish) macules, plaques, or nodules. * **Promontory Sign:** A characteristic histological feature where small vessels appear to protrude into larger, ectatic vascular spaces. * **Treatment:** Highly Active Antiretroviral Therapy (HAART) is the mainstay for AIDS-related KS; localized lesions may be treated with radiotherapy or intralesional vinblastine.

Q: Koenen tumor is seen in which of the following conditions?

Tuberous sclerosis. **Explanation:** **Koenen tumor** (also known as periungual or subungual fibroma) is a classic cutaneous marker of **Tuberous Sclerosis Complex (TSC)**. These are smooth, flesh-colored, or pinkish longitudinal growths that emerge from the nail fold or under the nail plate. They typically appear during adolescence or early adulthood and are one of the major diagnostic criteria for TSC. **Why the correct answer is right:** * **Tuberous Sclerosis (B):** This is an autosomal dominant neurocutaneous syndrome caused by mutations in *TSC1* (hamartin) or *TSC2* (tuberin) genes. Koenen tumors are pathognomonic hamartomas of the connective tissue found in about 50% of adult TSC patients. **Why the incorrect options are wrong:** * **Neurofibromatosis (A):** Characterized by Café-au-lait spots, Lisch nodules, and neurofibromas (plexiform or cutaneous), but not periungual fibromas. * **Sturge-Weber Syndrome (C):** A vascular neurocutaneous syndrome characterized by a Port-wine stain (Nevus Flammeus) in the trigeminal distribution and leptomeningeal angiomas. * **Tuberculosis (D):** While the name "Tuberous" sounds similar, TSC is a genetic disorder unrelated to the *Mycobacterium tuberculosis* infection. **High-Yield Clinical Pearls for TSC (Vogt’s Triad: Adenoma sebaceum, Mental retardation, Epilepsy):** 1. **Ash-leaf spots:** Earliest sign (hypopigmented macules, best seen under Wood’s lamp). 2. **Adenoma Sebaceum:** Actually angiofibromas, typically in a butterfly distribution on the face. 3. **Shagreen patch:** Connective tissue nevus (leathery plaque) usually on the lower back. 4. **Confetti lesions:** Multiple small hypopigmented macules on the limbs. 5. **Internal findings:** Cardiac rhabdomyomas, Renal Angiomyolipomas (AML), and Subependymal Giant Cell Astrocytomas (SEGA).

Q: Which of the following are predisposing factors for skin cancer?

Smoking and Ultraviolet light. **Explanation:** The development of skin cancer is a multifactorial process involving environmental exposures and chronic tissue damage. **1. Why Option A is Correct:** * **Ultraviolet (UV) Light:** This is the most significant risk factor for non-melanoma skin cancers (NMSC) and melanoma. UV radiation causes direct DNA damage (forming pyrimidine dimers) and generates reactive oxygen species, leading to mutations in tumor suppressor genes like *TP53*. * **Smoking:** Tobacco smoke contains systemic carcinogens (e.g., polycyclic aromatic hydrocarbons). In dermatology, smoking is specifically a strong independent risk factor for **Squamous Cell Carcinoma (SCC)**, particularly of the lip and oral cavity, due to both chemical irritation and immunosuppressive effects. **2. Analysis of Incorrect Options:** * **Chronic Ulcers (Options B & C):** While a chronic non-healing ulcer (like a Marjolin’s ulcer arising in a burn scar or osteomyelitis sinus) is a known precursor to SCC, these options are less comprehensive than Option A. In the context of competitive exams, UV light is the primary "universal" risk factor that must be included. * **Infrared Light (Option D):** Infrared radiation is primarily associated with heat. While chronic heat exposure can cause *Erythema Ab Igne*, which rarely progresses to SCC, it is not a major or common predisposing factor compared to UV light. **High-Yield Clinical Pearls for NEET-PG:** * **Marjolin’s Ulcer:** A classic exam favorite; it refers to SCC arising in sites of chronic inflammation, scars, or chronic ulcers. * **Xeroderma Pigmentosum:** An autosomal recessive repair defect (nucleotide excision repair) leading to extreme UV sensitivity and early-onset skin cancers. * **Arsenic Exposure:** Associated with multiple BCCs and SCCs, often appearing on the palms and soles. * **Most Common Skin Cancer:** Basal Cell Carcinoma (BCC); however, SCC has a higher potential for metastasis.

Q: Which of the following lesions shows characteristic anagen, catagen, and telogen phases?

Keratoacanthoma. **Explanation:** **Keratoacanthoma (KA)** is a common, rapidly growing epithelial tumor that originates from the **pilosebaceous unit** (specifically the hair follicle neck). Its unique biological behavior mimics the physiological **hair cycle**, which is why it exhibits characteristic anagen, catagen, and telogen phases: 1. **Anagen-like phase:** Rapid proliferative growth (usually over 4–6 weeks), resulting in a dome-shaped nodule with a central keratinous plug. 2. **Catagen-like phase:** A period of stability or "plateau" where growth ceases. 3. **Telogen-like phase:** Spontaneous involution or regression, often leaving a puckered scar. **Analysis of Incorrect Options:** * **Verruca vulgaris:** This is a viral wart caused by Human Papillomavirus (HPV). It is characterized by epidermal hyperplasia (acanthosis), hyperkeratosis, and koilocytosis, but it does not follow the cyclical phases of a hair follicle. * **Squamous papilloma:** A benign proliferation of stratified squamous epithelium. While it is a pedunculated growth, it lacks the follicular origin and the programmed regression seen in Keratoacanthoma. **High-Yield Clinical Pearls for NEET-PG:** * **Clinical Appearance:** "Volcano-like" appearance (dome-shaped with a central keratin crater). * **Histopathology:** Shows a "cup-shaped" invagination with "lips" of overhanging epidermis and a central keratin plug. * **Dilemma:** It is histologically very similar to **well-differentiated Squamous Cell Carcinoma (SCC)**; many pathologists now classify it as "SCC, keratoacanthoma type." * **Muir-Torre Syndrome:** Multiple keratoacanthomas are associated with this syndrome (internal sebaceous tumors + visceral malignancies, usually GI).

Skin Tumors Indian Medical PG Practice Questions and MCQs

Question 1: What is the dermatological sign associated with carcinoma of the stomach?

A. Palmoplantar keratoderma
B. Acquired ichthyosis
C. Acanthosis Nigrans (Correct Answer)
D. Acrokeratosis paraneopiastica

Explanation: **Explanation:** **Acanthosis Nigricans (AN)** is the correct answer. While AN is most commonly associated with insulin resistance and obesity (Benign AN), its sudden, severe, and widespread onset in an older individual—often involving the palms (tripe palms) and mucous membranes—is a classic **paraneoplastic syndrome**. **Malignant Acanthosis Nigricans** is most frequently associated with **adenocarcinomas of the gastrointestinal tract**, with **stomach cancer** being the most common (approx. 50-60% of cases). It is thought to be mediated by tumor-secreted growth factors like Transforming Growth Factor-alpha (TGF-α) acting on epidermal EGF receptors. **Analysis of Incorrect Options:** * **A. Palmoplantar Keratoderma (PPK):** While acquired PPK can be paraneoplastic (Howel-Evans Syndrome), it is specifically linked to **Esophageal carcinoma**, not primarily the stomach. * **B. Acquired Ichthyosis:** This sudden onset of "fish-like" scaling in adulthood is most strongly associated with **lymphomas** (specifically Hodgkin’s Lymphoma), rather than gastric malignancies. * **D. Acrokeratosis Paraneoplastica (Bazex Syndrome):** This presents with psoriasiform plaques on acral sites (ears, nose, fingers). It is highly specific for squamous cell carcinomas of the **upper aerodigestive tract** (head, neck, and esophagus). **High-Yield Clinical Pearls for NEET-PG:** * **Tripe Palms:** When AN affects the palms, appearing velvety and rugose, it is 90% predictive of internal malignancy. If seen with AN, think **Stomach CA**; if seen alone, think **Lung CA**. * **Leser-Trélat Sign:** The sudden eruption of multiple Seborrheic Keratoses is another major cutaneous marker for **Gastric Adenocarcinoma**. * **Sister Mary Joseph Nodule:** A palpable nodule at the umbilicus representing metastasis from a pelvic or abdominal malignancy (most commonly Stomach CA).

Question 2: Which of the following conditions shows susceptibility to squamous cell carcinoma in the skin?

A. Epidermodysplasia verruciformis
B. Actinic keratosis
C. Xeroderma pigmentosum
D. All the above (Correct Answer)

Explanation: **Explanation:** Squamous Cell Carcinoma (SCC) of the skin is a malignant tumor of epidermal keratinocytes. Its development is often preceded by precancerous lesions or genetic conditions that impair the skin's ability to repair DNA damage or control viral oncogenesis. * **Epidermodysplasia Verruciformis (EV):** This is a rare genetic disorder characterized by an abnormal susceptibility to **Human Papillomaviruses (HPV)**, particularly types 5 and 8. Patients develop chronic wart-like lesions that have a high propensity (30-60%) for transforming into SCC, especially on sun-exposed areas. * **Actinic Keratosis (AK):** Also known as solar keratosis, these are considered **premalignant** lesions. They represent the earliest clinical stage of SCC in situ. Histologically, they show keratinocyte atypia; if left untreated, approximately 1-10% progress to invasive SCC. * **Xeroderma Pigmentosum (XP):** This is an autosomal recessive disorder caused by a defect in **Nucleotide Excision Repair (NER)**. Patients cannot repair DNA damage caused by UV radiation, leading to a 10,000-fold increased risk of developing skin cancers, including SCC, Basal Cell Carcinoma (BCC), and Melanoma at a very young age. Since all three conditions are well-documented precursors or risk factors for SCC, **Option D** is the correct answer. **High-Yield Clinical Pearls for NEET-PG:** * **Marjolin’s Ulcer:** SCC arising in chronic scars, non-healing ulcers, or burn sites. It is more aggressive than UV-induced SCC. * **Bowen’s Disease:** A clinical term for SCC in situ (full-thickness atypia without basement membrane invasion). * **Arsenic Exposure:** A systemic risk factor that typically leads to multiple SCCs on the palms and soles. * **Most common site for SCC:** Lower lip (whereas BCC is more common on the upper lip).

Question 3: Which of the following lesions shows characteristic anagen, catagen, and telogen phases?

A. Keratoacanthoma (Correct Answer)
B. Basal cell carcinoma
C. Leukoplakia
D. Squamous cell carcinoma

Explanation: **Explanation:** **Keratoacanthoma (KA)** is a common, rapidly growing epithelial tumor that clinically and histologically resembles Squamous Cell Carcinoma (SCC). The hallmark of KA is its unique life cycle, which mimics the **hair follicle cycle**. It originates from the follicular infundibulum and progresses through three distinct stages: 1. **Proliferative phase (Anagen-like):** Rapid growth over 4–6 weeks, forming a dome-shaped nodule with a central keratinous plug. 2. **Stationary phase (Catagen-like):** Growth ceases, and the lesion stabilizes. 3. **Involutional phase (Telogen-like):** Spontaneous regression occurs over weeks to months, often leaving a puckered scar. **Analysis of Incorrect Options:** * **Basal Cell Carcinoma (BCC):** The most common skin cancer. It is characterized by slow growth, "pearly" borders, and telangiectasia. It does not undergo spontaneous regression or follow a follicular cycle. * **Leukoplakia:** A clinical term for a white patch on the mucosa that cannot be characterized as any other disease. It is a premalignant condition, not a follicular-derived tumor. * **Squamous Cell Carcinoma (SCC):** While KA is often considered a well-differentiated variant of SCC, true SCC is characterized by progressive, uncontrolled growth and invasion without a programmed involutional phase. **High-Yield NEET-PG Pearls:** * **Clinical Appearance:** "Volcano-like" appearance (dome-shaped with a central keratin plug). * **Histology:** Shows a central keratin-filled crater with "lips" or "buttresses" of overhanging epithelium. * **Syndrome Association:** Multiple keratoacanthomas are seen in **Muir-Torre Syndrome** (associated with internal malignancies) and **Grzybowski type** (generalized eruptive KAs). * **Management:** Despite spontaneous regression, surgical excision is usually recommended because it is difficult to distinguish KA from aggressive SCC.

Question 4: A patient presents with multiple, pearly papules on the face. Biopsy reveals a malignant tumor. Which of the following microscopic features would most likely be observed?

A. Cytoplasmic viral inclusions
B. Keratin
C. Melanin
D. Palisading nuclei (Correct Answer)

Explanation: **Explanation:** The clinical presentation of **pearly papules** on the face, often with telangiectasia, is the classic description of **Basal Cell Carcinoma (BCC)**, the most common skin cancer. **Why the correct answer is right:** The hallmark histopathological feature of BCC is the presence of nests or islands of basaloid cells (cells with large, dark nuclei and scant cytoplasm). At the periphery of these nests, the nuclei align themselves in a parallel, fence-like arrangement known as **peripheral palisading**. Additionally, a characteristic "retraction artifact" (clefting) is often seen between the tumor nests and the surrounding stroma. **Why the incorrect options are wrong:** * **A. Cytoplasmic viral inclusions:** These are characteristic of viral infections like Molluscum Contagiosum (Henderson-Patterson bodies) or HPV (koilocytes), not malignant tumors like BCC. * **B. Keratin:** While BCC can occasionally show focal keratinization (Basosquamous variant), **Keratin pearls** are the pathognomonic feature of **Squamous Cell Carcinoma (SCC)**. * **C. Melanin:** While "Pigmented BCC" exists, melanin is the defining feature of **Melanoma**. In a general question about pearly papules, palisading is the more specific diagnostic marker for BCC. **High-Yield NEET-PG Pearls:** * **Most common site:** Upper 2/3rd of the face (above the line joining the earlobe to the angle of the mouth). * **Risk Factor:** Chronic UV exposure; also associated with **Gorlin Syndrome** (PTCH gene mutation). * **Behavior:** Locally invasive ("Rodent ulcer") but rarely metastasizes. * **Treatment of choice:** Surgical excision or Mohs Micrographic Surgery (for high-risk areas).

Question 5: What is true regarding Kaposi's sarcoma?

A. Can occur even when CD4 count is normal
B. Human Herpesvirus 8 (HHV-8) is the etiological agent
C. Koebner's phenomenon may be observed with it
D. All of the above are true (Correct Answer)

Explanation: **Explanation:** Kaposi’s Sarcoma (KS) is a multicentric angioproliferative tumor derived from vascular and lymphatic endothelial cells. It is uniquely associated with **Human Herpesvirus 8 (HHV-8)**, also known as Kaposi Sarcoma-associated Herpesvirus (KSHV). * **Option A (CD4 Count):** While KS is an AIDS-defining illness typically seen when CD4 counts are <200 cells/mm³, it can occur in individuals with **normal CD4 counts**. This is particularly true in the "Classic (Sporadic)" variant seen in elderly Mediterranean men and the "Endemic (African)" variant, where HIV infection is not a prerequisite. * **Option B (Etiology):** HHV-8 is the definitive causative agent across all four clinical types (Classic, Endemic, Iatrogenic/Transplant-related, and AIDS-associated). The virus induces spindle cell proliferation and angiogenesis. * **Option C (Koebner’s Phenomenon):** KS is one of the few neoplastic conditions that can exhibit the **Pseudo-Koebner phenomenon**, where new lesions develop at sites of trauma or previous injury. **Clinical Pearls for NEET-PG:** * **Histopathology:** Characterized by **spindle-shaped cells**, slit-like vascular spaces containing extravasated RBCs, and **hyaline droplets**. * **Clinical Presentation:** Presents as palpable, non-blanching, violaceous (purplish) macules, plaques, or nodules. * **Promontory Sign:** A characteristic histological feature where small vessels appear to protrude into larger, ectatic vascular spaces. * **Treatment:** Highly Active Antiretroviral Therapy (HAART) is the mainstay for AIDS-related KS; localized lesions may be treated with radiotherapy or intralesional vinblastine.

Question 6: Koenen tumor is seen in which of the following conditions?

A. Neurofibromatosis
B. Tuberous sclerosis (Correct Answer)
C. Sturge-Weber syndrome
D. Tuberculosis

Explanation: **Explanation:** **Koenen tumor** (also known as periungual or subungual fibroma) is a classic cutaneous marker of **Tuberous Sclerosis Complex (TSC)**. These are smooth, flesh-colored, or pinkish longitudinal growths that emerge from the nail fold or under the nail plate. They typically appear during adolescence or early adulthood and are one of the major diagnostic criteria for TSC. **Why the correct answer is right:** * **Tuberous Sclerosis (B):** This is an autosomal dominant neurocutaneous syndrome caused by mutations in *TSC1* (hamartin) or *TSC2* (tuberin) genes. Koenen tumors are pathognomonic hamartomas of the connective tissue found in about 50% of adult TSC patients. **Why the incorrect options are wrong:** * **Neurofibromatosis (A):** Characterized by Café-au-lait spots, Lisch nodules, and neurofibromas (plexiform or cutaneous), but not periungual fibromas. * **Sturge-Weber Syndrome (C):** A vascular neurocutaneous syndrome characterized by a Port-wine stain (Nevus Flammeus) in the trigeminal distribution and leptomeningeal angiomas. * **Tuberculosis (D):** While the name "Tuberous" sounds similar, TSC is a genetic disorder unrelated to the *Mycobacterium tuberculosis* infection. **High-Yield Clinical Pearls for TSC (Vogt’s Triad: Adenoma sebaceum, Mental retardation, Epilepsy):** 1. **Ash-leaf spots:** Earliest sign (hypopigmented macules, best seen under Wood’s lamp). 2. **Adenoma Sebaceum:** Actually angiofibromas, typically in a butterfly distribution on the face. 3. **Shagreen patch:** Connective tissue nevus (leathery plaque) usually on the lower back. 4. **Confetti lesions:** Multiple small hypopigmented macules on the limbs. 5. **Internal findings:** Cardiac rhabdomyomas, Renal Angiomyolipomas (AML), and Subependymal Giant Cell Astrocytomas (SEGA).

Question 7: Which of the following are predisposing factors for skin cancer?

A. Smoking and Ultraviolet light (Correct Answer)
B. Chronic ulcer
C. Smoking and Chronic ulcer
D. Smoking and Infrared light

Explanation: **Explanation:** The development of skin cancer is a multifactorial process involving environmental exposures and chronic tissue damage. **1. Why Option A is Correct:** * **Ultraviolet (UV) Light:** This is the most significant risk factor for non-melanoma skin cancers (NMSC) and melanoma. UV radiation causes direct DNA damage (forming pyrimidine dimers) and generates reactive oxygen species, leading to mutations in tumor suppressor genes like *TP53*. * **Smoking:** Tobacco smoke contains systemic carcinogens (e.g., polycyclic aromatic hydrocarbons). In dermatology, smoking is specifically a strong independent risk factor for **Squamous Cell Carcinoma (SCC)**, particularly of the lip and oral cavity, due to both chemical irritation and immunosuppressive effects. **2. Analysis of Incorrect Options:** * **Chronic Ulcers (Options B & C):** While a chronic non-healing ulcer (like a Marjolin’s ulcer arising in a burn scar or osteomyelitis sinus) is a known precursor to SCC, these options are less comprehensive than Option A. In the context of competitive exams, UV light is the primary "universal" risk factor that must be included. * **Infrared Light (Option D):** Infrared radiation is primarily associated with heat. While chronic heat exposure can cause *Erythema Ab Igne*, which rarely progresses to SCC, it is not a major or common predisposing factor compared to UV light. **High-Yield Clinical Pearls for NEET-PG:** * **Marjolin’s Ulcer:** A classic exam favorite; it refers to SCC arising in sites of chronic inflammation, scars, or chronic ulcers. * **Xeroderma Pigmentosum:** An autosomal recessive repair defect (nucleotide excision repair) leading to extreme UV sensitivity and early-onset skin cancers. * **Arsenic Exposure:** Associated with multiple BCCs and SCCs, often appearing on the palms and soles. * **Most Common Skin Cancer:** Basal Cell Carcinoma (BCC); however, SCC has a higher potential for metastasis.

Question 8: A patient presents with a history of placing tobacco in the buccal vestibule and chewing betel quid. What is the likely diagnosis for the resulting lesion?

A. Pan chewer’s lesion
B. Tobacco pouch keratosis
C. Leukoplakia
D. Both Pan chewer’s lesion and Tobacco pouch keratosis (Correct Answer)

Explanation: ### Explanation The correct answer is **D (Both Pan chewer’s lesion and Tobacco pouch keratosis)** because the patient’s habits involve two distinct components that produce specific clinical presentations. **1. Why Option D is Correct:** * **Tobacco Pouch Keratosis:** This is a specific reaction to the placement of smokeless tobacco (snuff or chewing tobacco) in the buccal vestibule. It typically presents as a white, wrinkled, or "corrugated" plaque. The severity depends on the duration and frequency of tobacco contact. * **Pan Chewer’s Lesion:** This occurs due to the habit of chewing betel quid (pan), which often contains areca nut, slaked lime, and tobacco. It results in a characteristic brownish-red staining of the mucosa and teeth, often accompanied by a rough, desquamating surface or "chewer's mucosa." Since the patient uses both tobacco in the vestibule and chews betel quid, both pathological processes are likely to be present simultaneously. **2. Why other options are incorrect:** * **Options A & B:** These are partially correct but incomplete. Choosing only one ignores the clinical impact of the other habit mentioned in the history. * **Option C (Leukoplakia):** While tobacco use is a major risk factor for leukoplakia, the term is a clinical diagnosis of exclusion (a white patch that cannot be characterized as any other disease). The question describes specific habits that lead to the more specific diagnoses of Pan chewer’s lesion and Tobacco pouch keratosis. **3. NEET-PG High-Yield Pearls:** * **Malignant Potential:** Tobacco pouch keratosis has a low malignant transformation rate, but long-term use significantly increases the risk of **Verrucous Carcinoma (Ackerman’s tumor)**. * **Oral Submucous Fibrosis (OSMF):** Associated primarily with areca nut (betel nut). It is characterized by "burning sensation" on eating spicy food and progressive "trismus" (restricted mouth opening) due to vertical fibrous bands. * **Reversibility:** Tobacco pouch keratosis is often reversible if the habit is discontinued early, whereas OSMF is generally irreversible.

Question 9: Which of the following lesions shows characteristic anagen, catagen, and telogen phases?

A. Verruca vulgaris
B. Squamous papilloma
C. Keratoacanthoma (Correct Answer)
D. All of the above

Explanation: **Explanation:** **Keratoacanthoma (KA)** is a common, rapidly growing epithelial tumor that originates from the **pilosebaceous unit** (specifically the hair follicle neck). Its unique biological behavior mimics the physiological **hair cycle**, which is why it exhibits characteristic anagen, catagen, and telogen phases: 1. **Anagen-like phase:** Rapid proliferative growth (usually over 4–6 weeks), resulting in a dome-shaped nodule with a central keratinous plug. 2. **Catagen-like phase:** A period of stability or "plateau" where growth ceases. 3. **Telogen-like phase:** Spontaneous involution or regression, often leaving a puckered scar. **Analysis of Incorrect Options:** * **Verruca vulgaris:** This is a viral wart caused by Human Papillomavirus (HPV). It is characterized by epidermal hyperplasia (acanthosis), hyperkeratosis, and koilocytosis, but it does not follow the cyclical phases of a hair follicle. * **Squamous papilloma:** A benign proliferation of stratified squamous epithelium. While it is a pedunculated growth, it lacks the follicular origin and the programmed regression seen in Keratoacanthoma. **High-Yield Clinical Pearls for NEET-PG:** * **Clinical Appearance:** "Volcano-like" appearance (dome-shaped with a central keratin crater). * **Histopathology:** Shows a "cup-shaped" invagination with "lips" of overhanging epidermis and a central keratin plug. * **Dilemma:** It is histologically very similar to **well-differentiated Squamous Cell Carcinoma (SCC)**; many pathologists now classify it as "SCC, keratoacanthoma type." * **Muir-Torre Syndrome:** Multiple keratoacanthomas are associated with this syndrome (internal sebaceous tumors + visceral malignancies, usually GI).

Question 10: A 12-year-old girl presents with a 0.4 cm slightly raised, strawberry-colored nodule in the skin of the abdomen below the umbilicus. It has been present for many years and has not changed in color or size. What is the most likely diagnosis?

A. Carcinoma
B. Melanoma
C. Hemangioma (Correct Answer)
D. Lymphoma

Explanation: **Explanation:** The clinical presentation of a **"strawberry-colored"** nodule that has been stable for many years in a pediatric patient is classic for a **Hemangioma**. **Why Hemangioma is correct:** Hemangiomas are common benign vascular tumors of childhood. The "strawberry" appearance (bright red, lobulated) is characteristic of **Capillary Hemangiomas**. While many infantile hemangiomas undergo a phase of rapid growth followed by involution, some variants (like non-involuting congenital hemangiomas) remain stable in size and color over years. The location and color are hallmark signs of a vascular proliferation. **Why other options are incorrect:** * **Carcinoma (A):** Basal cell or squamous cell carcinomas are extremely rare in a 12-year-old without predisposing conditions (like Xeroderma Pigmentosum). They typically present as pearly nodules or non-healing ulcers, not strawberry-colored lesions. * **Melanoma (B):** While melanoma can occur in children, it typically presents as a pigmented (black/brown) lesion with asymmetrical borders and color variegation (ABCDE criteria), rather than a stable, bright red nodule. * **Lymphoma (C):** Cutaneous lymphoma usually presents as scaly patches, plaques, or deep-seated violaceous nodules/tumors, often associated with systemic symptoms, rather than a superficial strawberry-like lesion. **NEET-PG High-Yield Pearls:** * **Infantile Hemangioma:** Most common benign tumor of childhood; usually appears shortly after birth, grows rapidly (proliferative phase), and then slowly disappears (involution). * **Kasabach-Merritt Syndrome:** A dangerous complication where a large vascular tumor (usually Tufted Angioma or Kaposiform Hemangioendothelioma) causes consumptive coagulopathy and thrombocytopenia. * **GLUT-1 Marker:** Positive in infantile hemangiomas, helping differentiate them from other vascular malformations. * **Treatment:** Propranolol (oral) is currently the first-line treatment for complicated infantile hemangiomas.

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