Skin Tumors — MCQs

Skin Tumors Indian Medical PG Practice Questions and MCQs

Question 91: What is the most common type of nevus found in the oral cavity?

A. Intramucosal nevi (Correct Answer)
B. Blue nevi
C. Junctional nevi
D. Spitz nevi

Explanation: **Explanation:** Melanocytic nevi of the oral cavity are relatively uncommon compared to cutaneous nevi, but they follow a specific distribution pattern. The **Intramucosal nevus** is the most common histological subtype, accounting for approximately **55% to 64%** of all oral nevi. **Why Intramucosal Nevi is correct:** In an intramucosal nevus, the nevus cells are located entirely within the connective tissue (lamina propria), with no involvement of the basement membrane zone. This is the mucosal equivalent of the *intradermal nevus* found on the skin. The most common site for these lesions is the hard palate, followed by the buccal mucosa. **Analysis of Incorrect Options:** * **Blue nevi:** This is the second most common type (approx. 25–30%). It is characterized by spindle-shaped melanocytes located deep within the connective tissue. * **Junctional nevi:** These are rare in the oral cavity (approx. 3–5%). Here, the nevus cells are limited to the basal layer of the epithelium. In skin, these are common in children, but they rarely persist in the oral mucosa. * **Spitz nevi:** These are extremely rare in the oral cavity. They are characterized by large spindle and/or epithelioid cells and are typically seen on the skin of children. **High-Yield Clinical Pearls for NEET-PG:** * **Most common site:** Hard palate (40%), followed by the gingiva. * **Clinical appearance:** Typically a small, well-circumscribed, symmetrical, pigmented macule or papule. * **Management:** Because oral nevi can clinically mimic **early oral melanoma**, the standard of care is **excisional biopsy** for definitive diagnosis. * **Compound Nevus:** This is the third most common type, showing features of both junctional and intramucosal nests.

Question 92: In the Clarke's levels of tumor invasion of malignant melanoma, level 3 refers to which layer of the skin?

A. All tumor cells above the basement membrane
B. Invasion into the reticular dermis
C. Invasion into the loose connective tissue of the papillary dermis
D. Tumor cells at the junction of the papillary and reticular dermis (Correct Answer)

Explanation: **Explanation:** **Clark’s Levels of Invasion** is a histopathological staging system used to describe the anatomical depth of penetration of a malignant melanoma into the layers of the skin. The correct answer is **Option D**. In **Level 3**, the tumor cells fill the entire papillary dermis and accumulate at the **interface/junction between the papillary and reticular dermis**, but they do not yet penetrate the thick bundles of the reticular dermis. **Analysis of Options:** * **Option A (Level 1):** This represents "Melanoma in-situ." All tumor cells are confined to the epidermis, above the basement membrane. * **Option C (Level 2):** This involves invasion into the **papillary dermis** (loose connective tissue), but the cells do not fill the entire layer or reach the junction. * **Option B (Level 4):** This represents invasion into the **reticular dermis** (the deep, collagen-rich layer). * **Level 5 (Not listed):** This involves invasion into the **subcutaneous fat (hypodermis)**. **High-Yield Clinical Pearls for NEET-PG:** * **Breslow’s Depth vs. Clark’s Level:** While Clark’s Level measures anatomical layers, **Breslow’s Depth** (measured in millimeters using an ocular micrometer) is the **most important prognostic factor** and is currently preferred for T-staging in the AJCC TNM system. * **Prognosis:** The deeper the Clark level, the higher the risk of metastasis and the poorer the prognosis. * **Mnemonic for Clark's:** **E**very **P**erson **F**eels **R**eally **S**ad (Epidermis, Papillary, Fills papillary, Reticular, Subcutaneous).

Question 93: All of the following statements regarding actinic keratosis are true, EXCEPT:

A. Increased incidence in people with light skin
B. Increased incidence in organ transplant recipients
C. Topical 5-fluorouracil can be used in treating the disease
D. Usually seen in young individuals (Correct Answer)

Explanation: **Explanation:** Actinic Keratosis (AK), also known as solar keratosis, is a **premature skin lesion** caused by cumulative, long-term exposure to ultraviolet (UV) radiation. It is considered a **pre-malignant** condition that can progress to Squamous Cell Carcinoma (SCC). **Why Option D is the Correct Answer (The Exception):** Actinic keratosis is a disease of **older individuals** (typically >50 years). Because it results from the cumulative damage of UV radiation over decades, it is rarely seen in young individuals unless they have specific genetic predispositions to UV sensitivity (e.g., Xeroderma Pigmentosum). **Analysis of Other Options:** * **Option A:** AK is significantly more common in individuals with **Fair Skin (Fitzpatrick types I and II)** due to lower melanin protection against UV rays. * **Option B:** Immunosuppression is a major risk factor. **Organ transplant recipients** have a 250-fold increased risk of developing AKs and subsequent SCC due to long-term immunosuppressive therapy. * **Option C:** **Topical 5-Fluorouracil (5-FU)** is a gold-standard treatment for "field cancerization." It inhibits thymidylate synthase, targeting rapidly dividing dysplastic cells. Other treatments include Imiquimod, Diclofenac gel, and Cryotherapy. **High-Yield Clinical Pearls for NEET-PG:** * **Clinical Presentation:** "Sandpaper-like" texture on palpation; erythematous, scaly plaques on sun-exposed areas (scalp, face, ears). * **Histopathology:** Shows **parakeratosis** (retention of nuclei in the stratum corneum) and **dysplasia** of the basal layer of the epidermis. * **Cutaneous Horn:** A clinical shape AK can take; the base must be biopsied to rule out SCC. * **Spreading Pigmented Actinic Keratosis (SPAK):** A variant that mimics melanoma.

Question 94: Most severe type of malignant melanoma most commonly arises from which of the following?

A. Junctional nevus
B. Arising de novo (Correct Answer)
C. Lentigo
D. Dermal nevus

Explanation: **Explanation:** **1. Why "Arising de novo" is correct:** The majority of malignant melanomas (approximately **70-80%**) arise **de novo** (from normal-appearing skin) rather than from a pre-existing nevus. Melanomas arising de novo are often associated with a more aggressive biological behavior and a higher risk of metastasis compared to those arising from a pre-existing lesion. This is a critical concept in dermatology: while patients are often told to watch their "moles," the most dangerous melanomas frequently appear as entirely new lesions. **2. Why the other options are incorrect:** * **Junctional Nevus:** While a junctional nevus has the potential for malignant transformation (as the melanocytes are located at the dermo-epidermal junction), it accounts for only a minority of cases. * **Lentigo:** Lentigo maligna is a subtype of melanoma in situ that occurs on sun-damaged skin. While it can progress to Lentigo Maligna Melanoma, it is generally slower-growing and less common than de novo presentations. * **Dermal Nevus:** Intradermal nevi have virtually zero malignant potential because the melanocytes have migrated entirely into the dermis and are considered "mature" or senescent. **3. NEET-PG High-Yield Pearls:** * **Most common site:** Back (men) and Lower limbs (women). * **Most common subtype:** Superficial Spreading Melanoma (SSM). * **Most aggressive subtype:** Nodular Melanoma (due to early vertical growth phase). * **Prognostic Indicator:** **Breslow’s Depth** (vertical thickness in mm) is the most important prognostic factor. * **ABCDE Criteria:** **A**symmetry, **B**order irregularity, **C**olor variation, **D**iameter >6mm, **E**volving. * **Radial vs. Vertical Growth:** Prognosis worsens significantly once the tumor enters the vertical growth phase.

Question 95: What is the vertical measurement in millimeters from the granular cell layer to the deepest part of a tumor used in melanoma for prognosis?

A. Breslow's method (Correct Answer)
B. Clarks's method
C. Thomas method
D. Ashpit's method

Explanation: ### Explanation **1. Why Breslow’s Method is Correct:** Breslow’s depth is the most important prognostic factor in localized cutaneous melanoma. It is a **quantitative** measurement using an ocular micrometer to measure the vertical distance from the **top of the granular cell layer** (or the base of an ulcer) to the **deepest point of tumor invasion** in the dermis or subcutaneous tissue. This measurement is recorded in millimeters (mm) and directly correlates with the risk of metastasis and overall survival. **2. Why the Other Options are Incorrect:** * **Clark’s Method:** This is a **qualitative** staging system based on the **anatomical level** of invasion (e.g., Level I: Epidermis; Level II: Papillary dermis; Level III: Filling papillary dermis; Level IV: Reticular dermis; Level V: Subcutaneous fat). While historically significant, it is less predictive than Breslow’s depth and is no longer the primary staging tool. * **Thomas and Ashpit’s Methods:** These are not recognized staging or measurement systems in dermatopathology for melanoma. **3. Clinical Pearls for NEET-PG:** * **T-Staging:** The AJCC staging for melanoma is primarily based on Breslow’s thickness (e.g., T1: ≤1.0 mm, T2: 1.01–2.0 mm, etc.). * **Ulceration:** The presence of ulceration (loss of epidermis over the tumor) automatically upgrades the "T" stage (e.g., T1a vs. T1b) and worsens the prognosis. * **Surgical Margins:** The width of the surgical excision margin is determined by the Breslow thickness (e.g., 1 cm margin for thickness <1 mm; 2 cm margin for thickness >2 mm). * **Sentinel Lymph Node Biopsy (SLNB):** Generally indicated for tumors ≥0.8 mm or those <0.8 mm with ulceration.

Question 96: Which condition is characterized by the following lesion?

A. Neurofibromatosis type 1 (NF1) (Correct Answer)
B. Neurofibromatosis type 2 (NF2)
C. Tuberous sclerosis
D. Von Hippel-Lindau disease (VHL)

Explanation: ***Neurofibromatosis type 1 (NF1)*** • Characterized by **café-au-lait macules** (light brown spots) and **cutaneous neurofibromas** as hallmark skin lesions that help establish the diagnosis. • Additional features include **axillary/inguinal freckling** and **Lisch nodules** (iris hamartomas), making skin findings central to NF1 diagnosis. *Neurofibromatosis type 2 (NF2)* • Primarily presents with **bilateral vestibular schwannomas** causing hearing loss, with minimal to no characteristic skin lesions. • Skin manifestations are rare and not diagnostic features, unlike the prominent cutaneous findings in NF1. *Tuberous sclerosis* • Characterized by distinctive skin lesions including **ash-leaf macules** (hypopigmented spots), **shagreen patches** (leathery plaques), and **adenoma sebaceum** (facial angiofibromas). • These lesions are morphologically different from the café-au-lait spots and neurofibromas seen in NF1. *Von Hippel-Lindau disease (VHL)* • Primarily affects internal organs with **retinal hemangioblastomas**, **cerebellar hemangioblastomas**, and **renal cell carcinomas**. • Does not have characteristic primary skin lesions as a diagnostic feature, unlike the other neurocutaneous syndromes.

Question 97: Actinic keratosis is a precursor to which of the following malignancies?

A. Basal cell carcinoma
B. Squamous cell carcinoma (Correct Answer)
C. Malignant melanoma
D. Epithelial cell carcinoma

Explanation: **Explanation:** **Actinic Keratosis (AK)**, also known as solar keratosis, is a common premalignant skin lesion caused by chronic exposure to ultraviolet (UV) radiation. It represents a proliferation of atypical epidermal keratinocytes. **Why Squamous Cell Carcinoma (SCC) is correct:** Actinic keratosis is considered a direct precursor to **invasive Squamous Cell Carcinoma**. Histologically, AK shows dysplasia in the lower layers of the epidermis; when this dysplasia involves the full thickness of the epidermis, it is termed *SCC in situ* (Bowen’s disease). If the atypical cells breach the dermo-epidermal junction and invade the dermis, it becomes invasive SCC. Approximately 60% of all SCCs arise from pre-existing AKs. **Why other options are incorrect:** * **A. Basal Cell Carcinoma (BCC):** While BCC is also caused by UV radiation, it typically arises *de novo* from the basal layer of the epidermis or hair follicles, not from AK. * **C. Malignant Melanoma:** This malignancy arises from melanocytes (pigment-producing cells). Its precursor lesions are typically dysplastic nevi or Lentigo Maligna, not AK. * **D. Epithelial Cell Carcinoma:** This is a broad, non-specific term. SCC is a specific type of epithelial carcinoma, making Option B the more precise and clinically accurate answer. **High-Yield Clinical Pearls for NEET-PG:** * **Clinical Presentation:** "Sandpaper-like" texture on sun-exposed areas (face, scalp, ears). * **Histology:** Characterized by **parakeratosis** (retained nuclei in the stratum corneum) and **flag sign** (alternating orthokeratosis and parakeratosis). * **Treatment of Choice:** **Cryotherapy** (for individual lesions) or **Topical 5-Fluorouracil (5-FU)** and **Imiquimod** (for field cancerization). * **Cutaneous Horn:** A clinical shape that can develop on top of an AK; the base must be biopsied to rule out SCC.

Question 98: Mycosis fungoides is a type of:

A. Papillitis
B. Fungal infection
C. T cell Lymphoma (Correct Answer)
D. Paracytic infection

Explanation: **Explanation:** **Mycosis Fungoides (MF)** is the most common form of **Cutaneous T-cell Lymphoma (CTCL)**. Despite its name, it is not a fungal infection; it is a primary skin malignancy characterized by the clonal proliferation of skin-homing **CD4+ T-helper cells**. The name historically stems from the "mushroom-like" appearance of the large skin tumors seen in advanced stages. **Analysis of Options:** * **Option C (Correct):** MF is a low-grade extranodal non-Hodgkin lymphoma. It typically follows a chronic, indolent course progressing through three classic stages: **Patch → Plaque → Tumor**. * **Option B (Incorrect):** While the name "Mycosis" suggests a fungus, this is a historical misnomer. True fungal infections of the skin (like Tinea) are treated with antifungals, whereas MF requires skin-directed therapies (steroids, UV light) or systemic chemotherapy. * **Option A & D (Incorrect):** Papillitis refers to inflammation (often of the optic nerve), and parasitic infections (like Scabies) are caused by organisms, not malignant cell transformations. **High-Yield Clinical Pearls for NEET-PG:** * **Pautrier’s Microabscesses:** The pathognomonic histological feature (clusters of malignant T-cells within the epidermis). * **Epidermotropism:** The hallmark movement of atypical lymphocytes into the epidermis without significant spongiosis. * **Sézary Syndrome:** The leukemic (systemic) variant of CTCL characterized by the triad of erythroderma, lymphadenopathy, and circulating atypical T-cells (Sézary cells with **cerebriform nuclei**). * **Treatment:** Early-stage MF is often managed with **PUVA therapy** or topical nitrogen mustard.

Question 99: Which of the following is considered the least malignant melanoma?

A. Lentigo maligna (Correct Answer)
B. Superficial spreading
C. Nodular
D. Amelanotic

Explanation: **Explanation:** The malignancy of melanoma is primarily determined by its growth phase and the speed at which it invades the dermis (vertical growth). **Lentigo Maligna (LM)** is considered the least malignant because it has a prolonged **radial growth phase** that can last for years or even decades before entering the vertical growth phase. It typically occurs on sun-damaged skin in elderly patients and remains confined to the epidermis (in situ) for a long duration. Once it becomes invasive, it is termed Lentigo Maligna Melanoma, but its overall progression is the slowest among the clinical subtypes. **Analysis of Incorrect Options:** * **Superficial Spreading Melanoma:** This is the most common clinical subtype. While it also has a radial growth phase, it progresses to the vertical growth phase much faster than Lentigo Maligna. * **Nodular Melanoma:** This is the **most aggressive** form. It lacks a radial growth phase entirely and starts with a vertical growth phase from the onset, leading to early metastasis and a poor prognosis. * **Amelanotic Melanoma:** This is a clinical variant that lacks pigment. It is often diagnosed late because it mimics benign lesions (like skin tags or pyogenic granuloma), leading to a worse prognosis due to delayed intervention. **High-Yield Clinical Pearls for NEET-PG:** * **Most common type overall:** Superficial Spreading Melanoma. * **Most common type in Indians/Asians:** Acral Lentiginous Melanoma (occurs on palms, soles, and subungual areas). * **Best prognostic indicator:** **Breslow’s Depth** (vertical thickness measured in mm). * **ABCDE Criteria:** Asymmetry, Border irregularity, Color variation, Diameter >6mm, Evolving. * **Hutchinson’s Sign:** Periungual extension of pigment onto the nail fold; highly suggestive of subungual melanoma.

Question 100: Acanthosis nigricans is a known paraneoplastic sign associated with which of the following conditions?

A. Colonic carcinoma
B. Freckle
C. Squamous cell carcinoma of the skin
D. Carcinoma of the breast (Correct Answer)

Explanation: **Explanation:** **Acanthosis Nigricans (AN)** is a dermatological condition characterized by hyperpigmented, velvety plaques typically found in intertriginous areas (axilla, neck, groin). While most commonly associated with insulin resistance and obesity, its sudden, severe onset in an older individual—known as **Malignant Acanthosis Nigricans**—serves as a classic paraneoplastic syndrome. **Why Option D is Correct:** Malignant AN is most frequently associated with **intra-abdominal adenocarcinomas**, with **Gastric Carcinoma** being the most common (approx. 55-60%). However, it is also strongly associated with other adenocarcinomas, including **Carcinoma of the Breast** and lung cancer. The pathogenesis involves tumor-secreted growth factors, primarily **Transforming Growth Factor-alpha (TGF-α)**, which stimulates epidermal keratinocytes and fibroblasts via the Epidermal Growth Factor Receptor (EGFR). **Analysis of Incorrect Options:** * **Option A (Colonic Carcinoma):** While internal malignancies can cause AN, gastric cancer is significantly more common than colonic cancer in this context. * **Option B (Freckle):** This is a benign melanocytic lesion (ephelis) caused by increased melanin production, not a systemic or paraneoplastic condition. * **Option C (SCC of the skin):** Squamous cell carcinoma is a localized cutaneous malignancy and is not typically associated with the systemic growth factor release required to trigger AN. **High-Yield Clinical Pearls for NEET-PG:** * **Tripe Palms:** When AN involves the palms (velvety rugosity), it is highly suggestive of internal malignancy (Lung cancer if alone; Gastric cancer if accompanied by AN). * **Leser-Trélat Sign:** The sudden eruption of multiple seborrheic keratoses, often seen alongside malignant AN. * **Most common site:** The posterior neck is the most frequent site for all forms of AN. * **Key Growth Factor:** TGF-α is the primary mediator in the malignant variant.

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Benign Epithelial Tumors

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Premalignant Epidermal Tumors

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Basal Cell Carcinoma

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Squamous Cell Carcinoma

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Melanocytic Nevi

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Melanoma

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Merkel Cell Carcinoma

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Vascular Tumors and Malformations

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Cutaneous Lymphomas

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Soft Tissue Tumors

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Metastatic Skin Tumors

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Skin Cancer Prevention and Screening

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Skin Tumors — MCQs

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