Skin Tumors Practice Questions

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

Diabetes Insipidus. **Explanation:** **Xanthoma disseminatum (XD)** is a rare, benign, 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 histiocytic infiltrates involve the pituitary stalk or the hypothalamus. This leads to a deficiency in Vasopressin (ADH), resulting in **central Diabetes Insipidus**. The cutaneous lesions typically appear as small, reddish-brown to yellow papules and nodules symmetrically distributed over the face and flexural areas (axilla, groin). 2. **Why the other options are incorrect:** * **A. Down’s Syndrome:** While associated with certain dermatological conditions like syringomas and alopecia areata, it has no known association with XD. * **C. Lymphoma:** XD is a benign histiocytic proliferation. While some other xanthomatous conditions (like Necrobiotic Xanthogranuloma) are associated with paraproteinemias or malignancies, XD is not typically linked to lymphoma. * **D. Carcinoma of Pancreas:** There is no established clinical link between XD and pancreatic malignancy. **High-Yield Clinical Pearls for NEET-PG:** * **Normolipemic State:** Unlike most other xanthomas, Xanthoma Disseminatum occurs in patients with **normal lipid profiles**. * **The Triad:** Cutaneous lesions + Mucosal lesions (upper airway/oral) + Diabetes Insipidus. * **Montgomery’s Syndrome:** Another name for Xanthoma Disseminatum. * **Histology:** Features "Touton giant cells" and foamy macrophages (histiocytes) that are **S100 negative** and **CD68 positive** (confirming non-LCH origin).

Q: An enlarging, conical cutaneous horn that has been present for more than a year projects 0.5 cm from a 0.7-cm base on the left lateral cheek of the face of a 58-year-old farmer. This lesion is excised, and microscopic examination shows basal cell hyperplasia. Some of the basal cells show nuclear atypicalities. This is associated with marked hyperkeratosis and parakeratosis. Which of the following lesions best accounts for these findings?

Actinic keratosis. **Explanation:** The clinical presentation and histopathology point directly to **Actinic Keratosis (AK)**. **1. Why Actinic Keratosis is correct:** * **Clinical Context:** AK is a premalignant lesion caused by chronic UV radiation exposure, typically seen in older individuals with outdoor occupations (e.g., a farmer). * **Morphology:** It often presents as a "cutaneous horn" (hyperkeratotic projection). * **Histopathology:** The hallmark is **dysplasia of the lower layers of the epidermis** (basal cell hyperplasia with nuclear atypia/pleomorphism). The stratum corneum shows alternating **hyperkeratosis and parakeratosis** (retention of nuclei), often described as a "flag sign." **2. Why other options are incorrect:** * **Verruca vulgaris:** Caused by HPV; histology shows koilocytosis (vacuolated cells) and prominent granulosum layer with coarse keratohyalin granules, not basal atypia. * **Keratoacanthoma:** Characterized by a rapid growth phase and a central keratin-filled crater. Histology shows well-differentiated squamous epithelium, not limited to the basal layer. * **Dysplastic nevus:** This is a melanocytic lesion. Histology would show architectural atypia of melanocytes (nesting) at the dermo-epidermal junction, not epidermal basal cell hyperplasia. **Clinical Pearls for NEET-PG:** * **Precursor:** AK is a precursor to **Squamous Cell Carcinoma (SCC)**. The risk of progression is roughly 0.1% to 10%. * **Spreading:** When dysplasia involves the full thickness of the epidermis, it is termed **Bowen’s Disease** (SCC in situ). * **Treatment of choice:** Cryotherapy (for single lesions) or topical 5-Fluorouracil/Imiquimod (for field cancerization). * **Key Histology Term:** "Crowing" of the basal layer (budding into the dermis) and "Flag sign" (alternating orthokeratosis and parakeratosis).

Question 1

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

Accepted Answer

Acanthosis Nigrans

Answer

Palmoplantar keratoderma

Answer

Acquired ichthyosis

Answer

Acrokeratosis paraneopiastica

Question 2

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

Accepted Answer

Keratoacanthoma

Answer

Basal cell carcinoma

Answer

Leukoplakia

Answer

Squamous cell carcinoma

Question 3

Xanthoma disseminatum is associated with which of the following conditions?

Accepted Answer

Diabetes Insipidus

Answer

Down's Syndrome

Answer

Lymphoma

Answer

Carcinoma of Pancreas

Question 4

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?

Accepted Answer

Hemangioma

Answer

Carcinoma

Answer

Melanoma

Answer

Lymphoma

Question 5

An enlarging, conical cutaneous horn that has been present for more than a year projects 0.5 cm from a 0.7-cm base on the left lateral cheek of the face of a 58-year-old farmer. This lesion is excised, and microscopic examination shows basal cell hyperplasia. Some of the basal cells show nuclear atypicalities. This is associated with marked hyperkeratosis and parakeratosis. Which of the following lesions best accounts for these findings?

Accepted Answer

Actinic keratosis

Answer

Verruca vulgaris

Answer

Keratoacanthoma

Answer

Dysplastic nevus

Skin Tumors — MCQs

Skin Tumors — MCQs

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