Skin Tumors Practice Questions

Q: Multiple cutaneous sebaceous adenomas are seen in which of the following conditions?

Muir Torre syndrome. **Explanation:** **Muir-Torre Syndrome (MTS)** is the correct answer. It is a rare autosomal dominant genodermatosis and is considered a phenotypic variant of **Lynch Syndrome (Hereditary Non-Polyposis Colorectal Cancer - HNPCC)**. * **Pathophysiology:** It is caused by germline mutations in DNA mismatch repair (MMR) genes, most commonly **MSH2** (90%) and MLH1. * **Clinical Presentation:** The hallmark is the association of at least one **sebaceous gland tumor** (sebaceous adenoma, sebaceoma, or sebaceous carcinoma) and at least one **internal malignancy** (most commonly colorectal, followed by urogenital). Sebaceous adenomas are the most characteristic cutaneous marker for this syndrome. **Analysis of Incorrect Options:** * **Cowden Syndrome:** Part of the PTEN hamartoma tumor syndrome. Characterized by multiple **trichilemmomas** (hair follicle tumors), oral papillomas, and acral keratoses. It carries a high risk of breast, thyroid, and endometrial cancers. * **Gardner Syndrome:** A variant of Familial Adenomatous Polyposis (FAP). Cutaneous markers include **epidermoid cysts**, desmoid tumors, and lipomas, alongside intestinal polyposis and osteomas. * **Turcot Syndrome:** Characterized by the association of colonic polyposis with **Central Nervous System (CNS) tumors** (e.g., medulloblastoma or glioblastoma). **High-Yield Clinical Pearls for NEET-PG:** * **Muir-Torre Marker:** The **sebaceous adenoma** is the most specific cutaneous marker for internal malignancy in MTS. * **Keratoacanthomas:** MTS is also associated with multiple keratoacanthomas, often with sebaceous differentiation. * **Screening:** Any patient presenting with a sebaceous adenoma (outside the head and neck) should be screened for internal malignancies via colonoscopy.

Q: Which of the following is NOT considered a premalignant condition?

Acanthosis nigricans. **Explanation:** The correct answer is **Acanthosis nigricans (C)**. **Why it is the correct answer:** Acanthosis nigricans is a reactive dermatosis characterized by hyperpigmented, velvety plaques, typically in intertriginous areas. While it is frequently a **cutaneous marker of internal malignancy** (most commonly gastric adenocarcinoma when it appears suddenly and extensively), the skin lesions themselves are **benign** and do not undergo malignant transformation. Therefore, it is a "paraneoplastic syndrome" rather than a "premalignant condition." **Why the other options are incorrect:** * **Bowen’s Disease (A):** This is defined as **Squamous Cell Carcinoma (SCC) in situ**. It involves the full thickness of the epidermis but has not breached the dermo-epidermal junction. If left untreated, it can progress to invasive SCC. * **Leukoplakia (B):** A clinical term for a white patch on the mucosa that cannot be rubbed off. It is a classic premalignant condition of the oral cavity, often associated with tobacco use, with a risk of transforming into SCC. * **Solar Keratosis (D):** Also known as Actinic Keratosis, these are rough, scaly patches on sun-exposed skin. They are considered the earliest stage in the biological spectrum of SCC. **NEET-PG High-Yield Pearls:** * **Malignant Acanthosis Nigricans:** Usually associated with **TGF-alpha** production by the tumor. It is most commonly associated with **Gastric Adenocarcinoma**. * **Tripe Palms:** A variant of acanthosis nigricans involving the palms; if seen with AN, it highly suggests internal malignancy (Lung or Gastric). * **Erythroplasia of Queyrat:** This is Bowen's disease specifically occurring on the glans penis.

Q: Mycosis fungoides is classified as which of the following?

A type of cutaneous lymphoma. **Explanation:** **Mycosis Fungoides (MF)** is the most common form of **Cutaneous T-Cell Lymphoma (CTCL)**. Despite its name, it is a primary skin malignancy characterized by the clonal proliferation of skin-homing **CD4+ T-helper cells**. It typically follows a chronic, indolent course progressing through three classic stages: Patch, Plaque, and Tumor. **Analysis of Options:** * **Option D (Correct):** MF is a low-grade extranodal non-Hodgkin lymphoma. The diagnosis is confirmed histologically by the presence of **Pautrier’s microabscesses** (clusters of atypical lymphocytes in the epidermis). * **Option A:** The name "Mycosis Fungoides" is a historical misnomer coined by Baron Alibert because the tumor stage resembled mushrooms; it has no fungal etiology. * **Option B:** While it is a hematologic malignancy, it is a lymphoma (localized to tissue) rather than leukemia (primarily in blood/bone marrow). However, if it leukemizes (malignant cells in peripheral blood), it is termed **Sézary Syndrome**. * **Option C:** While advanced MF can progress to **erythroderma** (the "Red Man Syndrome"), the disease itself is classified by its pathological origin (lymphoma) rather than a clinical sign (erythroderma), which can be caused by many other conditions like psoriasis or drug reactions. **High-Yield Clinical Pearls for NEET-PG:** * **Hallmark Histology:** Epidermotropism (lymphocytes lining up along the basal layer) and **Pautrier’s microabscesses**. * **Sézary Syndrome Triad:** Erythroderma, lymphadenopathy, and atypical circulating T-cells (Sézary cells with **cerebriform nuclei**). * **Treatment:** Early stage is managed with skin-directed therapies (topical steroids, PUVA, Narrowband UVB); advanced stages may require systemic chemotherapy or electron beam therapy.

Q: A 15-year-old girl has developed multiple skin nodules over the past 10 years. Physical examination reveals 20 scattered, 0.3-cm to 1-cm, firm nodules on her trunk and extremities, along with 12 light brown macules averaging 2 to 5 cm in diameter on the trunk. Slit-lamp examination shows pigmented nodules in the iris. A sibling and a parent are similarly affected, and genetic analysis shows a loss-of-function mutation. Which of the following inheritance patterns is most likely present in this family?

Autosomal dominant. ### Explanation The clinical presentation described is a classic case of **Neurofibromatosis Type 1 (NF1)**, also known as von Recklinghausen disease. **Why Autosomal Dominant is correct:** NF1 is one of the most common **autosomal dominant** disorders, caused by a mutation in the *NF1* gene on chromosome 17, which encodes the protein **neurofibromin** (a tumor suppressor). * **Clinical Evidence:** The patient exhibits the classic triad: multiple **neurofibromas** (skin nodules), **Café-au-lait spots** (light brown macules), and **Lisch nodules** (pigmented iris hamartomas). * **Inheritance:** The fact that a parent and sibling are also affected, spanning multiple generations, is a hallmark of autosomal dominant inheritance. It has high penetrance but variable expressivity. **Why other options are incorrect:** * **Autosomal recessive:** These disorders typically appear in a single generation (horizontal transmission) and often involve enzyme deficiencies. NF1 involves a structural/tumor suppressor protein and shows vertical transmission. * **Mitochondrial:** This follows maternal inheritance (all children of an affected mother, none of an affected father). Here, the involvement of a "parent" (unspecified gender) and the known genetics of NF1 rule this out. * **Multifactorial:** This involves multiple genes and environmental factors (e.g., diabetes, hypertension). NF1 is a monogenic (single-gene) disorder. **Clinical Pearls for NEET-PG:** * **Diagnostic Criteria (NIH):** Requires $\geq$ 2 of: $\geq$ 6 Café-au-lait spots, $\geq$ 2 neurofibromas, axillary/inguinal freckling (**Crowe sign**), Lisch nodules, optic glioma, or a first-degree relative with NF1. * **Genetics:** Chromosome **17** (NF**1** has **17** letters). * **Associated Tumors:** Increased risk of Pheochromocytoma, Wilms tumor, and Malignant Peripheral Nerve Sheath Tumors (MPNST).

Q: Which type of nevus is typically found deep within the connective tissue?

Blue nevi. **Explanation:** The correct answer is **Blue nevi**. **1. Why Blue Nevi is Correct:** Blue nevi are characterized by the proliferation of spindle-shaped, dendritic melanocytes located **deep within the dermis** (connective tissue). Unlike common nevi, these melanocytes fail to migrate to the dermo-epidermal junction during embryogenesis and remain trapped in the deeper layers. The characteristic blue color is a result of the **Tyndall effect**: shorter wavelengths of light (blue) are reflected by the deep-seated melanin, while longer wavelengths (red) are absorbed by the overlying tissue. **2. Why Other Options are Incorrect:** * **Junctional nevi:** In these lesions, the nests of melanocytes are located strictly at the **dermo-epidermal junction**. They are clinically flat (macular) and represent the earliest stage of a common acquired nevus. * **Intramucosal nevi:** This term refers to the location (mucous membranes, such as the oral cavity) rather than the depth within the connective tissue architecture. While they are the mucosal equivalent of intradermal nevi, the "Blue nevus" is the classic histological example of deep dermal/connective tissue deposition. **3. NEET-PG High-Yield Pearls:** * **Common Blue Nevus:** Most common on the dorsum of hands and feet. * **Cellular Blue Nevus:** A larger variant, often found on the buttocks or sacrococcygeal region; it must be differentiated from malignant melanoma. * **Histology:** Look for heavily pigmented, elongated, dendritic cells interspersed among thickened collagen bundles. * **Progression:** Common acquired nevi usually follow a sequence: Junctional $\rightarrow$ Compound $\rightarrow$ Intradermal (where cells "drop" into the dermis but are not as deep or dendritic as blue nevi).

Q: Xanthoma disseminatum is associated with which of the following conditions?

Diabetes insipidus. **Explanation:** **Xanthoma Disseminatum (XD)** is a rare, benign form of **Non-Langerhans Cell Histiocytosis (non-LCH)**. It is characterized by the triad of cutaneous xanthomas, mucosal involvement, and diabetes insipidus. 1. **Why Diabetes Insipidus is correct:** The underlying pathophysiology involves the proliferation of histiocytes in various tissues. In approximately **40% of cases**, these histiocytes infiltrate the hypothalamic-pituitary axis (specifically the posterior pituitary or infundibulum), leading to a deficiency in Antidiuretic Hormone (ADH). This results in **central diabetes insipidus**, manifesting as polyuria and polydipsia. 2. **Why other options are incorrect:** * **Down Syndrome:** Associated with Syringomas (periorbital) and Alopecia Areata, but has no specific link to XD. * **Lymphoma:** While some histiocytic disorders (like Hemophagocytic Lymphohistiocytosis) can be associated with malignancies, XD is typically a benign, self-limiting (though chronic) cutaneous-mucosal process not triggered by lymphoma. * **Carcinoma of the Pancreas:** Associated with **Trousseau sign** (thrombophlebitis) or **Necrolytic Migratory Erythema** (if glucagonoma), but not with non-LCH. **High-Yield Clinical Pearls for NEET-PG:** * **Clinical Presentation:** Characterized by hundreds of small, red-brown to orange-yellow papules and nodules, typically in a **symmetrical distribution** involving flexural and intertriginous areas (axilla, groin). * **Mucosal Involvement:** Occurs in 40-60% of cases, affecting the upper aerodigestive tract (can cause hoarseness or dyspnea). * **Lipid Profile:** Unlike most other xanthomas, Xanthoma Disseminatum is **normolipemic** (serum lipid levels are normal). * **Histology:** Features "Touton giant cells" and foamy macrophages (CD68 positive, S100 negative, CD1a negative).

Q: What is the most common clinicopathologic class of melanoma during the radial growth phase?

Superficial spreading. **Explanation:** **Superficial Spreading Melanoma (SSM)** is the most common clinicopathologic subtype of melanoma, accounting for approximately 70% of all cases. During its **radial growth phase**, the tumor cells spread laterally within the epidermis and superficial dermis. This phase can last for months to years before transitioning into the vertical growth phase (dermal invasion), making it the most frequently encountered type during early clinical evaluation. **Analysis of Options:** * **Superficial Spreading (Correct):** It typically presents as a variegated, pigmented plaque with irregular borders. It is most common on the backs of men and the lower limbs of women. * **Lentigo Maligna (Incorrect):** This subtype occurs on chronically sun-damaged skin (usually the face of elderly patients). While it has a very long radial growth phase (often decades), it is less common overall than SSM. * **Acral Lentiginous (Incorrect):** This is the most common subtype in dark-skinned individuals (Asians and African Americans), occurring on palms, soles, and subungual areas. However, globally and statistically, it is less common than the superficial spreading type. **High-Yield Clinical Pearls for NEET-PG:** * **Most common type overall:** Superficial Spreading Melanoma. * **Most common type in India/Dark skin:** Acral Lentiginous Melanoma. * **Best prognostic factor:** **Breslow’s Depth** (vertical thickness measured from the granular layer to the deepest tumor cell). * **ABCDE Criteria:** Asymmetry, Border irregularity, Color variegation, Diameter >6mm, and Evolving. * **Nodular Melanoma:** Notable for having **no** identifiable radial growth phase; it begins in the vertical growth phase, leading to a poorer prognosis.

Question 1

Multiple cutaneous sebaceous adenomas are seen in which of the following conditions?

Accepted Answer

Muir Torre syndrome

Answer

Cowden syndrome

Answer

Gardner syndrome

Answer

Turcot syndrome

Question 2

Which of the following is NOT considered a premalignant condition?

Accepted Answer

Acanthosis nigricans

Answer

Bowen's disease

Answer

Leukoplakia

Answer

Solar keratosis

Question 3

Mycosis fungoides is classified as which of the following?

Accepted Answer

A type of cutaneous lymphoma

Answer

A fungal infection of the skin

Answer

A type of leukemia

Answer

A condition causing exfoliative erythroderma

Question 4

A 15-year-old girl has developed multiple skin nodules over the past 10 years. Physical examination reveals 20 scattered, 0.3-cm to 1-cm, firm nodules on her trunk and extremities, along with 12 light brown macules averaging 2 to 5 cm in diameter on the trunk. Slit-lamp examination shows pigmented nodules in the iris. A sibling and a parent are similarly affected, and genetic analysis shows a loss-of-function mutation. Which of the following inheritance patterns is most likely present in this family?

Accepted Answer

Autosomal dominant

Answer

Autosomal recessive

Answer

Mitochondrial

Answer

Multifactorial

Question 5

A 20-year-old female received treatment for bronchial asthma. She noticed a mole recently. Which characteristic of a mole carries a high risk for malignancy?

Accepted Answer

Irregular margin

Answer

Mole on the face

Answer

Size 6 mm

Answer

Hyperpigmentation

Question 6

Prognosis of melanoma depends on which of the following factors?

Accepted Answer

Duration of growth

Answer

Stage

Answer

Depth of melanoma on biopsy

Answer

Site

Question 7

Which type of nevus is typically found deep within the connective tissue?

Accepted Answer

Blue nevi

Answer

Junctional nevi

Answer

Intramucosal nevi

Answer

None of the above

Question 8

Which type of melanoma is malignant?

Accepted Answer

Junctional nevus

Answer

Blue nevus

Answer

Intradermal nevus

Answer

None of the above

Question 9

Xanthoma disseminatum is associated with which of the following conditions?

Accepted Answer

Diabetes insipidus

Answer

Down syndrome

Answer

Lymphoma

Answer

Carcinoma of the pancreas

Question 10

What is the most common clinicopathologic class of melanoma during the radial growth phase?

Accepted Answer

Superficial spreading

Answer

Acral lentigines

Answer

Lentigo maligna

Answer

None of the above

Skin Tumors — MCQs

Skin Tumors — MCQs

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