Skin Tumors Practice Questions

Q: Which of the following is the commonest site for a rodent ulcer?

Inner canthus of eye. **Explanation:** **Rodent Ulcer** is the clinical term for a slow-growing, locally invasive **Basal Cell Carcinoma (BCC)**. It is the most common skin cancer in humans, typically occurring on sun-exposed areas in elderly individuals. **Why Inner Canthus is Correct:** BCC has a strong predilection for the face, specifically above the line joining the lobe of the ear to the angle of the mouth (the "embryonic fusion lines"). The **inner canthus of the eye** is the most common specific site for a rodent ulcer. This area is particularly dangerous because the tumor can invade deeply into the orbit or the lacrimal system if not treated early. **Analysis of Incorrect Options:** * **Lips (A):** The lower lip is a classic site for **Squamous Cell Carcinoma (SCC)**, not BCC. BCC rarely affects the mucosal surfaces or the vermilion border of the lips. * **Outer Canthus (B):** While BCC can occur here, it is statistically less frequent than the inner canthus. * **Cheek (D):** The cheeks are a common site for various skin tumors, including BCC and SCC, but they do not represent the "most common" specific anatomical site for a rodent ulcer compared to the inner canthus. **High-Yield Clinical Pearls for NEET-PG:** * **Characteristic Feature:** A pearly, translucent border with **telangiectasia** (dilated capillaries) and a central "punched-out" ulcer. * **Metastasis:** BCC is notorious for being **locally aggressive** but rarely metastasizes (unlike SCC or Melanoma). * **Risk Factors:** Chronic UV exposure and arsenic poisoning. * **Pathology:** Histology shows "palisading" of nuclei at the periphery of tumor nests. * **Treatment of Choice:** Wide local excision or **Mohs Micrographic Surgery** (highest cure rate).

Q: Which is an aggressive type of cutaneous T-cell lymphoma?

Sezary syndrome. **Explanation:** Cutaneous T-cell Lymphomas (CTCL) are a heterogeneous group of extranodal non-Hodgkin lymphomas. The correct answer is **Sezary Syndrome (SS)** because it represents the leukemic, aggressive phase of CTCL. **1. Why Sezary Syndrome is correct:** Unlike Mycosis Fungoides, which is often indolent and skin-limited for years, Sezary Syndrome is characterized by a triad of **erythroderma** (generalized redness), **lymphadenopathy**, and the presence of **Sezary cells** (atypical T-cells with cerebriform nuclei) in the peripheral blood. It carries a significantly poorer prognosis with a median survival of approximately 2–4 years. **2. Why the other options are incorrect:** * **Mycosis Fungoides (MF):** This is the most common CTCL. It typically follows a slow, indolent course progressing through patch, plaque, and tumor stages over decades. * **Reticulum cell sarcoma:** This is an obsolete term formerly used to describe various high-grade lymphomas (now mostly classified under Diffuse Large B-cell Lymphoma). It is not a specific primary cutaneous T-cell lymphoma subtype. * **Panniculitis:** This is an inflammatory condition of the subcutaneous fat (e.g., Erythema Nodosum), not a primary malignancy, although "Subcutaneous panniculitis-like T-cell lymphoma" is a rare malignant variant. **Clinical Pearls for NEET-PG:** * **Pautrier’s Microabscess:** Pathognomonic histological feature of MF/SS (clusters of atypical T-cells in the epidermis). * **Immunophenotype:** Most CTCLs are **CD4+** (Helper T-cells). * **Diagnosis of SS:** Requires an absolute Sezary cell count of **≥1000 cells/mm³**. * **Treatment:** Early-stage MF uses skin-directed therapies (PUVA, topical steroids), while SS requires systemic therapy (Extracorporeal Photopheresis, Interferon-alpha).

Q: Keratoacanthoma is:

A self-healing nodular lesion with central ulceration. **Explanation:** **Keratoacanthoma (KA)** is a common, rapidly growing skin tumor that clinically and histologically resembles well-differentiated squamous cell carcinoma (SCC). **Why Option C is correct:** The hallmark of Keratoacanthoma is its unique **triphasic clinical course**: 1. **Proliferative phase:** Rapid growth over 4–6 weeks. 2. **Stationary phase:** Formation of a dome-shaped, skin-colored nodule with a characteristic **central keratinous plug** (crateriform appearance). 3. **Involutional phase:** Spontaneous regression over 6–12 months, often leaving a depressed scar. This "self-healing" nature is its defining feature. **Why other options are incorrect:** * **Option A:** It is not a type of Basal Cell Carcinoma (BCC). While it mimics SCC, BCC presents differently (pearly borders, telangiectasia) and does not regress spontaneously. * **Option B:** An infected sebaceous cyst presents with fluctuance, pain, and purulent discharge, lacking the central keratin plug and rapid symmetrical growth of KA. * **Option D:** It is not "pre-malignant" (like Actinic Keratosis); rather, it is often considered a **low-grade malignancy** or a variant of SCC that happens to regress. **High-Yield Clinical Pearls for NEET-PG:** * **Histology:** Shows a "cup-shaped" invagination with a central keratin plug and "overhanging edges" (lips) of the epidermis. * **Associations:** Multiple keratoacanthomas are seen in **Ferguson-Smith syndrome** (multiple self-healing) and **Grzybowski syndrome** (generalized eruptive). * **Muir-Torre Syndrome:** Keratoacanthomas associated with internal malignancies (especially GI tract). * **Management:** Despite its self-healing nature, surgical excision is usually the treatment of choice because it is difficult to distinguish from aggressive SCC.

Q: Which skin tumor is known as the "Turban tumor"?

Cutaneous cylindroma. **Explanation:** **Cutaneous Cylindroma** is the correct answer. It is a benign adnexal tumor originating from the sweat glands (eccrine or apocrine). When multiple cylindromas occur, they typically involve the scalp and can grow large enough to cover the entire cranium like a headpiece, earning the clinical nickname **"Turban tumor."** * **Histology (High Yield):** On biopsy, it shows a characteristic **"Jigsaw puzzle" appearance**, where nests of basaloid cells are surrounded by a thick, eosinophilic, PAS-positive hyaline sheath. * **Genetics:** Multiple cylindromas are associated with **Brooke-Spiegler Syndrome**, an autosomal dominant condition caused by a mutation in the **CYLD gene**. **Why the other options are incorrect:** * **Basal Cell Carcinoma (BCC):** The most common skin cancer, typically presenting as a pearly papule with telangiectasia or a "rodent ulcer," but it does not form a turban-like distribution. * **Squamous Cell Carcinoma (SCC):** Presents as an indurated, scaling plaque or ulcer, often associated with sun exposure or precursor lesions like actinic keratosis. * **Dermatofibroma:** A common benign fibrous nodule, usually found on the legs, characterized by the **"Dimple sign"** (central depression upon lateral pressure). **Clinical Pearls for NEET-PG:** 1. **Cylindroma:** Jigsaw puzzle pattern + CYLD gene + Turban tumor. 2. **Spiradenoma:** Often co-exists with cylindromas in Brooke-Spiegler Syndrome; these are characteristically **painful** skin tumors. 3. **Trichoepithelioma:** Another component of Brooke-Spiegler, presenting as multiple flesh-colored papules in the nasolabial folds.

Q: Which of the following melanomas does not have an in situ growth phase?

Nodular melanoma. **Explanation:** The growth of cutaneous melanoma is categorized into two phases: the **Radial Growth Phase (RGP)** and the **Vertical Growth Phase (VGP)**. The radial phase represents the "in situ" or intraepidermal stage where the tumor spreads horizontally within the epidermis before invading the deeper dermis. **Nodular Melanoma (NM)** is unique because it lacks an identifiable radial/in situ growth phase. From its inception, it exhibits a **Vertical Growth Phase**, characterized by the downward invasion of malignant melanocytes into the dermis. This rapid vertical progression is why NM typically presents as a fast-growing, deeply invasive nodule with a poorer prognosis compared to other subtypes. **Analysis of Other Options:** * **Superficial Spreading Melanoma (SSM):** The most common subtype; it has a prominent radial growth phase that can last for months to years before entering the vertical phase. * **Lentigo Maligna Melanoma (LMM):** Occurs on sun-damaged skin (especially the face of the elderly). It has a very prolonged in situ phase (Lentigo Maligna) that can last decades. * **Desmoplastic Melanoma:** A rare variant often associated with Lentigo Maligna; it typically evolves from an in situ precursor, though its dermal component is characterized by dense fibrosis. **NEET-PG High-Yield Pearls:** * **Most common melanoma overall:** Superficial Spreading Melanoma. * **Melanoma with the worst prognosis:** Nodular Melanoma (due to early VGP). * **Most common site for SSM:** Back (males), Lower limbs (females). * **Breslow’s Depth:** The most important prognostic factor for melanoma (measures the thickness from the granular layer to the deepest tumor cell). * **ABCDE Criteria:** Asymmetry, Border irregularity, Color variegation, Diameter >6mm, Evolving.

Q: Prognosis of malignant melanoma depends on which of the following factors?

Depth of invasion. **Explanation:** The prognosis of malignant melanoma is primarily determined by the **depth of invasion**, which is the most significant independent prognostic factor for localized disease. This is clinically quantified using the **Breslow Depth (Thickness)**. 1. **Why "Depth of Invasion" is correct:** The Breslow thickness measures the distance from the granular layer of the epidermis to the deepest point of tumor involvement in millimeters. As the depth increases, the likelihood of the tumor accessing dermal lymphatics and blood vessels increases, directly correlating with a higher risk of metastasis and lower survival rates. 2. **Why other options are incorrect:** * **Grade of tumor:** Unlike squamous cell carcinoma, "grading" (degree of differentiation) is not a standard prognostic tool for melanoma. * **Spread of tumor:** While spread (local or regional) is important, the initial management and survival prediction are most accurately dictated by the primary tumor's depth. * **Metastasis:** While the presence of metastasis indicates a poor prognosis (Stage IV), it is a *stage* of the disease rather than the primary *factor* used to determine the risk and surgical management of a primary lesion. **High-Yield Clinical Pearls for NEET-PG:** * **Breslow Depth:** The most important prognostic factor (measured in mm). * **Clark Level:** Measures the anatomical level of invasion (e.g., papillary vs. reticular dermis). It is now considered less reliable than Breslow depth. * **TNM Staging:** The 'T' (Tumor) stage in melanoma is defined by Breslow thickness and the presence/absence of **ulceration** (the second most important prognostic factor). * **Sentinel Lymph Node Biopsy (SLNB):** Usually indicated if Breslow thickness is **>0.8 mm** or if ulceration is present. * **Most common site:** Back (men), Legs (women). * **Most common type:** Superficial spreading melanoma.

Q: Which of the following features is most commonly seen?

Actinic keratoses. ***Actinic keratoses*** - Most common **pre-malignant skin lesion** in sun-exposed individuals, with **rough, scaly texture** on sun-damaged skin. - High prevalence in elderly populations with chronic **UV exposure**, representing the most frequently encountered lesion in dermatology practice. *Seborrheic keratoses* - **Benign lesions** with no malignant potential, appearing as **waxy, stuck-on plaques** typically on the trunk. - Less common than actinic keratoses and not associated with **sun exposure** or pre-malignant changes. *Molluscum contagiosum* - **Viral infection** caused by **poxvirus**, presenting as small **umbilicated papules** primarily in children. - Much less common than actinic keratoses and represents an **infectious process** rather than a sun-related lesion. *Basal cell carcinoma* - **Malignant tumor** that is less common than actinic keratoses, presenting as **pearly papules** with telangiectasia. - While the most common **skin cancer**, it occurs less frequently than the pre-malignant actinic keratoses in the general population.

Q: A 78-year-old woman has multiple long-standing lesions on her face and back. These well-circumscribed lesions are tan to brownish, slightly raised with a rough surface, and typically 0.5 to 1.5 cm in diameter. The clinician examining the patient is able to "peel away" parts of the lesion with the dull side of a scalpel blade. Which of the following diagnoses is most likely?

Seborrheic keratoses. **Explanation:** The clinical presentation describes **Seborrheic Keratosis (SK)**, a very common benign epidermal tumor seen in elderly individuals. The key diagnostic features in this vignette are the "stuck-on" appearance, the tan-to-brown color, and the characteristic **friability**. The ability to "peel away" or scrape off the greasy, waxy surface with a dull blade is a classic clinical sign of SK, reflecting its superficial nature and lack of deep dermal involvement. **Why the other options are incorrect:** * **Eczema:** Typically presents as pruritic, erythematous, ill-defined scaly patches or plaques. It does not form discrete, well-circumscribed, "stuck-on" pigmented nodules. * **Melanoma:** While melanoma can be pigmented, it is usually characterized by the ABCDE criteria (Asymmetry, Border irregularity, Color variegation, Diameter >6mm, and Evolution). Melanoma is an invasive malignancy and cannot be "peeled away" with a dull blade. * **Psoriasis:** Presents as well-demarcated erythematous plaques with silvery-white scales. While it shows the **Auspitz sign** (pinpoint bleeding upon scale removal), the lesions are not typically tan/brown or "stuck-on" in appearance. **High-Yield NEET-PG Pearls:** * **Histopathology:** Characterized by small, basaloid cells, hyperkeratosis, and pathognomonic **Horn cysts** (pseudo-horn cysts). * **Leser-Trélat Sign:** The sudden eruption of multiple seborrheic keratoses associated with internal malignancy (most commonly **Gastric Adenocarcinoma**). * **Dermatosis Papulosa Nigra:** A variant of SK seen in dark-skinned individuals, presenting as multiple small, hyperpigmented papules on the malar area. * **Treatment:** Usually unnecessary unless for cosmetic reasons; options include cryotherapy, curettage, or shave excision.

Q: Which of the following cutaneous malignancies does not metastasize through the lymphatics?

Basal cell carcinoma. **Explanation:** **Basal Cell Carcinoma (BCC)** is the correct answer because it is characterized by **local invasiveness** rather than metastatic potential. While it can be highly destructive to local tissues (earning it the name "Rodent Ulcer"), the rate of metastasis is extremely low (0.0028% to 0.5%). When metastasis does rarely occur, it is usually via the lymphatic route, but for the purposes of NEET-PG, BCC is classically defined as a tumor that "destroys locally but does not spread distantly." **Analysis of Incorrect Options:** * **Squamous Cell Carcinoma (SCC):** Unlike BCC, SCC has a significant risk of metastasis (approx. 2–5%), primarily through the **lymphatic system** to regional lymph nodes. * **Melanoma:** This is the most aggressive cutaneous malignancy. It spreads early and rapidly via both **lymphatics** (sentinel node involvement is a key prognostic factor) and hematogenous routes. * **Kaposi’s Sarcoma:** This is a vascular neoplasm caused by HHV-8. It frequently involves the **lymphatic channels** and can present with lymphadenopathy and visceral involvement. **High-Yield Clinical Pearls for NEET-PG:** * **BCC Origin:** Derived from the non-keratinizing cells of the basal layer of the epidermis. * **Most Common Site:** Face (above the line joining the angle of the mouth to the tragus). * **Histopathology:** Look for **"Peripheral Palisading"** of nuclei and retraction artifacts. * **Gold Standard Treatment:** Mohs Micrographic Surgery (highest cure rate). * **Inheritance:** Associated with **Gorlin Syndrome** (PTCH gene mutation).

Q: An HIV-positive patient presents with a characteristic lesion on the leg and a history of HHV-8 infection. What is the most likely diagnosis?

Kaposi sarcoma. **Explanation:** The clinical presentation of an HIV-positive patient with skin lesions and a confirmed **Human Herpesvirus-8 (HHV-8)** infection is the classic diagnostic triad for **Kaposi Sarcoma (KS)**. **Why Kaposi Sarcoma is correct:** Kaposi Sarcoma is a multicentric vascular neoplasm caused by HHV-8 (also known as KSHV). In the context of HIV/AIDS, it is an **AIDS-defining illness**. The virus infects endothelial cells, leading to spindle cell proliferation and neoangiogenesis. Lesions typically present as non-blanching, violaceous (purple) macules, plaques, or nodules, most commonly on the lower extremities, face, or oral mucosa. **Why other options are incorrect:** * **Lymphoma / Non-Hodgkin's Lymphoma (NHL):** While HIV patients are at a higher risk for NHL (e.g., Diffuse Large B-cell Lymphoma or Burkitt Lymphoma), these typically present as lymphadenopathy or systemic symptoms rather than characteristic vascular skin lesions associated with HHV-8. * **Malignant Melanoma:** This is a malignancy of melanocytes. While it presents as pigmented skin lesions, it is not etiologically linked to HHV-8 or specifically triggered by the HIV virus. **High-Yield Clinical Pearls for NEET-PG:** * **Histopathology:** Look for "spindle-shaped cells," "slit-like vascular spaces" containing RBCs, and "promontory sign." * **Variants:** There are four types: Classic (elderly Mediterranean men), Endemic (African), Iatrogenic (transplant-related), and Epidemic (AIDS-associated). * **Treatment:** Highly Active Antiretroviral Therapy (HAART) is the first line for AIDS-related KS. Localized lesions can be treated with intralesional vinblastine or cryotherapy. * **Differential Diagnosis:** Bacillary Angiomatosis (caused by *Bartonella henselae*), which also presents with purple nodules in HIV patients but shows neutrophilic infiltrate on biopsy.

Question 1

Which of the following is the commonest site for a rodent ulcer?

Accepted Answer

Inner canthus of eye

Answer

Lips

Answer

Outer canthus of eye

Answer

Cheek

Question 2

Which is an aggressive type of cutaneous T-cell lymphoma?

Accepted Answer

Sezary syndrome

Answer

Mycosis Fungoides

Answer

Reticulum cell sarcoma

Answer

Panniculitis

Question 3

Keratoacanthoma is:

Accepted Answer

A self-healing nodular lesion with central ulceration

Answer

A type of basal cell carcinoma

Answer

An infected sebaceous cyst

Answer

A pre-malignant disease

Question 4

Which skin tumor is known as the "Turban tumor"?

Accepted Answer

Cutaneous cylindroma

Answer

Basal cell carcinoma

Answer

Squamous cell carcinoma

Answer

Dermatofibroma

Question 5

Which of the following melanomas does not have an in situ growth phase?

Accepted Answer

Nodular melanoma

Answer

Superficial spreading melanoma

Answer

Lentigo maligna melanoma

Answer

Desmoplastic melanoma

Question 6

Prognosis of malignant melanoma depends on which of the following factors?

Accepted Answer

Depth of invasion

Answer

Grade of tumor

Answer

Spread of tumor

Answer

Metastasis

Question 7

Which of the following features is most commonly seen?

Accepted Answer

Actinic keratoses

Answer

Seborrheic keratoses

Answer

Molluscum contagiosum

Answer

Basal cell carcinoma

Question 8

A 78-year-old woman has multiple long-standing lesions on her face and back. These well-circumscribed lesions are tan to brownish, slightly raised with a rough surface, and typically 0.5 to 1.5 cm in diameter. The clinician examining the patient is able to "peel away" parts of the lesion with the dull side of a scalpel blade. Which of the following diagnoses is most likely?

Accepted Answer

Seborrheic keratoses

Answer

Eczema

Answer

Melanoma

Answer

Psoriasis

Question 9

Which of the following cutaneous malignancies does not metastasize through the lymphatics?

Accepted Answer

Basal cell carcinoma

Answer

Squamous cell carcinoma

Answer

Melanoma

Answer

Kaposi's sarcoma

Question 10

An HIV-positive patient presents with a characteristic lesion on the leg and a history of HHV-8 infection. What is the most likely diagnosis?

Accepted Answer

Kaposi sarcoma

Answer

Lymphoma

Answer

Malignant melanoma

Answer

Non-Hodgkin's lymphoma

Skin Tumors — MCQs

Skin Tumors — MCQs

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