Skin Tumors Practice Questions

Q: Which of the following skin findings is NOT typically associated with an underlying internal malignancy?

Granuloma annulare. **Explanation:** The correct answer is **Granuloma annulare**. This condition is a benign, self-limiting inflammatory dermatosis characterized by dermal papules arranged in an annular (ring-like) pattern. While it is classically associated with **Diabetes Mellitus**, it is not considered a paraneoplastic syndrome and does not typically signal an underlying internal malignancy. **Analysis of Incorrect Options:** * **Acanthosis Nigricans & Annular Erythema:** Malignant Acanthosis Nigricans (sudden onset, extensive, involving palms/soles) is strongly associated with **Gastric Adenocarcinoma**. * **Bullous Pyoderma & Migratory Necrotizing Erythema:** Bullous Pyoderma Gangrenosum is often linked to **Acute Myeloid Leukemia (AML)**. Necrolytic Migratory Erythema is the pathognomonic cutaneous marker for a **Glucagonoma** (alpha-cell tumor of the pancreas). * **Erythema Gyratum Repens:** This is one of the most specific paraneoplastic markers. It presents with a "wood-grain" appearance and is associated with **Lung, Breast, or Esophageal cancers** in over 80% of cases. **High-Yield Clinical Pearls for NEET-PG:** 1. **Leser-Trélat Sign:** Sudden eruption of multiple seborrheic keratoses; associated with GI malignancies. 2. **Bazex Syndrome (Acrokeratosis paraneoplastica):** Psoriasiform plaques on acral sites; associated with SCC of the upper aerodigestive tract. 3. **Sweet Syndrome:** Neutrophilic dermatosis often associated with AML. 4. **Tripe Palms:** Velvety thickening of palms; associated with Lung (if alone) or Gastric (if with Acanthosis Nigricans) cancer.

Q: Which of the following is NOT a risk factor for malignant melanoma?

HPV infection. **Explanation:** Malignant melanoma is a neoplasm arising from melanocytes. Its pathogenesis is primarily linked to genetic predisposition and ultraviolet (UV) radiation, rather than viral oncogenesis. **Why HPV infection is the correct answer:** Human Papillomavirus (HPV) is strongly associated with squamous cell carcinomas (especially of the cervix, anus, and oropharynx) and certain types of non-melanoma skin cancers (like Verrucous carcinoma). However, **HPV has no established causal link to malignant melanoma.** Melanoma is driven by mutations in the MAPK pathway (e.g., BRAF, NRAS), not viral integration. **Analysis of Incorrect Options:** * **Giant Congenital Nevi:** These are large pigmented lesions present at birth. They carry a significant lifetime risk (approx. 5–10%) of transforming into melanoma, especially if they exceed 20 cm in projected adult diameter. * **Family History:** About 10% of patients have a positive family history. Mutations in the **CDKN2A** gene (encoding p16) are the most common genetic risk factor identified in familial melanoma. * **Exposure to UV Light:** This is the most important environmental risk factor. **Intermittent, blistering sunburns** (especially in childhood) are more closely linked to melanoma than chronic, cumulative exposure. **High-Yield Clinical Pearls for NEET-PG:** * **Most common site:** Back (males), Lower limbs (females). * **Prognostic Marker:** **Breslow’s Depth** (vertical thickness) is the most important prognostic factor. * **ABCDE Criteria:** Asymmetry, Border irregularity, Color variation, Diameter >6mm, Evolving. * **Common Mutation:** **BRAF V600E** is the most frequent mutation (targeted by Vemurafenib). * **Tumor Marker:** S-100, HMB-45, and Melan-A.

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: 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: 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

Which of the following skin findings is NOT typically associated with an underlying internal malignancy?

Accepted Answer

Granuloma annulare

Answer

Acanthosis nigricans and annular erythema

Answer

Bullous pyoderma and migratory necrotizing erythema

Answer

Erythema gyratum repens

Question 2

All of the following are true statements about malignant melanoma except:

Accepted Answer

Acral lentiginous melanoma has a better prognosis than superficial spreading melanoma.

Answer

Clark's classification is used for prognosis.

Answer

Women generally have a better prognosis than men.

Answer

Limb perfusion is used for local treatment.

Question 3

Which of the following is NOT a risk factor for malignant melanoma?

Accepted Answer

HPV infection

Answer

Giant congenital nevi

Answer

Family history of melanoma

Answer

Exposure to UV light

Question 4

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 5

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 6

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 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

A 65-year-old light-complexioned male presents with a solitary scaly plaque-like lesion on his forearm, present for many years. The lesion is 0.5 cm in diameter. Shave biopsy reveals intraepithelial squamous cell carcinoma (Bowen's disease) that was incompletely excised. What is the most appropriate further treatment?

Accepted Answer

Excision and repair of this area, ensuring clear surgical margins

Answer

Wide excision of the lesion and sentinel node biopsy

Answer

Referral for local radiation therapy

Answer

No further treatment indicated

Question 9

Which type of melanoma is malignant?

Accepted Answer

Junctional nevus

Answer

Blue nevus

Answer

Intradermal nevus

Answer

None of the above

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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