Melanocytic Nevi Indian Medical PG Practice Questions and MCQs
Practice Indian Medical PG questions for Melanocytic Nevi. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Melanocytic Nevi Indian Medical PG Question 1: Identify the skin lesion shown in the image.
- A. Becker nevus (Correct Answer)
- B. Hypopigmented macule
- C. Spitz nevus
- D. Epidermal nevus
Melanocytic Nevi Explanation: ***Becker nevus***
- This image clearly shows a large, **hyperpigmented patch with overlying coarse terminal hairs**, characteristic of a Becker nevus.
- Becker nevi typically develop in adolescence and are often found on the shoulder or upper trunk, as seen here.
*Hypopigmented macule*
- A **hypopigmented macule** would appear as an area of skin with **reduced pigmentation** (lighter than the surrounding skin), which is contrary to the darker lesion shown.
- There would also be no indication of **increased hair growth** within a typical hypopigmented macule.
*Spitz nevus*
- A Spitz nevus is a benign melanocytic nevus often appearing as a **dome-shaped, pink or red papule or nodule**, commonly on the face or limbs.
- It does not present as a large, hairy, **hyperpigmented patch** as depicted in the image.
*Epidermal nevus*
- An epidermal nevus is a **congenital lesion** formed by an overgrowth of epidermal cells, but its appearance is typically a **verrucous (wart-like) plaque** or linearly arranged papules.
- While it can be hyperpigmented, it generally **lacks the prominent hypertrichosis** (excessive hair growth) seen in the image.
Melanocytic Nevi Indian Medical PG Question 2: Which of the following nevus types is most commonly associated with malignant melanoma development?
- A. Junctional nevus
- B. Intradermal nevus
- C. Blue nevus
- D. Dysplastic nevus (Correct Answer)
Melanocytic Nevi Explanation: ***Dysplastic nevus*** (Correct)
- **Dysplastic nevi** are considered precursor lesions and markers for increased risk of developing **malignant melanoma**.
- Individuals with multiple dysplastic nevi have a significantly higher lifetime risk of melanoma compared to the general population.
- Also known as **atypical nevi**, they show architectural disorder and cytologic atypia on histology.
*Junctional nevus* (Incorrect)
- **Junctional nevi** are benign moles with melanocytes located at the **dermo-epidermal junction**.
- While theoretically a melanoma can arise from any nevus, junctional nevi are less frequently associated with melanoma development than dysplastic nevi.
*Intradermal nevus* (Incorrect)
- **Intradermal nevi** are benign moles where the melanocytes are located entirely within the **dermis**.
- These nevi are generally stable, often appearing flesh-colored or light brown, and have a very low potential for malignant transformation.
*Blue nevus* (Incorrect)
- **Blue nevi** are benign lesions characterized by **deeply situated dermal melanocytes** that produce a blue or blue-black color due to the Tyndall effect.
- They are typically stable and have a very low risk of malignant transformation; however, rarely, an atypical blue nevus or cellular blue nevus can undergo malignant change.
Melanocytic Nevi Indian Medical PG Question 3: A farmer presented with a black mole on the cheek. It increased in size, more than 6mm with irregular borders and a central black lesion, what could be the diagnosis?
- A. Superficial spreading melanoma (Correct Answer)
- B. Acral lentigo melanoma
- C. Lentigo maligna melanoma
- D. Nodular melanoma
Melanocytic Nevi Explanation: ***Superficial spreading melanoma***
- This is the most common type of melanoma and often presents as a **mole with irregular borders**, varying colors, and a diameter greater than 6mm, consistent with the description.
- The lesion typically grows **radially** across the skin surface before beginning vertical growth, indicated by the increase in size.
*Acral lentigo melanoma*
- This type of melanoma primarily affects the **palms, soles, and nail beds**, which is inconsistent with a lesion on the cheek.
- It often appears as a **dark brown or black patch** that slowly enlarges, but its location is characteristic.
*Lentigo maligna melanoma*
- This melanoma typically occurs in **chronically sun-damaged skin** of the elderly, often on the head and neck, but usually presents as a **flat, irregularly shaped, tan or brown patch** with varying shades, which may not fit the description of a central black lesion within a larger mole.
- It has a dominant **radial growth phase** and progresses slowly over many years before developing a nodular component.
*Nodular melanoma*
- This type is characterized by its **rapid vertical growth** and appearance as a **raised, dark, often dome-shaped lesion** from the outset.
- While it can be black, the description of an "increased in size" mole with irregular borders and a central black lesion points more towards a spreading type rather than a rapidly growing nodule from the beginning.
Melanocytic Nevi Indian Medical PG Question 4: A giant congenital melanocytic nevus is usually of what size?
- A. 5-10cm
- B. 10-15 cm
- C. 15-20 cm
- D. 20 cm or greater (Correct Answer)
Melanocytic Nevi Explanation: ***20 cm or greater***
- A **giant congenital melanocytic nevus (GCMN)** is defined by its substantial size, typically measuring **20 cm or more in diameter** in an adult.
- This large size is a key feature distinguishing it from smaller congenital nevi and is associated with a **higher risk of malignant transformation** and neurological complications such as **neurocutaneous melanosis**.
*5-10cm*
- A nevus of this size would be classified as a **small to medium congenital melanocytic nevus**, not a giant one.
- While these nevi carry some risk of malignancy, it is significantly **lower than that of GCMN**.
*10-15 cm*
- This range falls under the category of a **medium congenital melanocytic nevus**.
- While larger than small nevi, it does not meet the established criteria for a **giant congenital melanocytic nevus**.
*15-20 cm*
- A nevus of 15-20 cm is considered a **large congenital melanocytic nevus**, but it is still usually classified just below the threshold for a true **giant congenital melanocytic nevus** which is typically 20 cm or more.
- Although it approaches the giant classification, the **20 cm demarcation** is critical for defining GCMN.
Melanocytic Nevi Indian Medical PG Question 5: What is the most likely diagnosis for a 15 mm hyperpigmented lesion on the shoulder that is enlarging and has hair growing from it?
- A. Melanocytic nevus
- B. Becker nevus (Correct Answer)
- C. Sebaceous nevus
- D. Comedo nevus
Melanocytic Nevi Explanation: ***Correct: Becker nevus***
This diagnosis is supported by the description of a **hyperpigmented lesion** that is **enlarging** and has **hair growing from it**, typically appearing during adolescence or young adulthood.
**Becker nevus** often presents as an **irregular, hyperpigmented patch**, usually on the shoulder or upper trunk, and is characteristically associated with **hypertrichosis** (increased terminal hair growth).
The combination of location (shoulder), enlargement, and hair growth in a 15 mm lesion is classic for Becker nevus.
*Incorrect: Melanocytic nevus*
While **melanocytic nevi** are hyperpigmented, they typically do not continue to **enlarge significantly** after childhood and generally do not develop new onset **hypertrichosis** as a primary feature.
The size (15 mm) and progressive growth combined with hair development are more characteristic of a Becker nevus than a common melanocytic nevus.
*Incorrect: Sebaceous nevus*
**Sebaceous nevi** are typically **yellow-orange to tan, waxy plaques**, often on the scalp or face, with a cobblestone or papillomatous texture.
They are not primarily characterized by **hyperpigmentation** and terminal hair growth, but rather by sebaceous gland proliferation.
*Incorrect: Comedo nevus*
A **comedo nevus** presents as a linear or unilateral group of **dilated follicular openings** filled with keratinous material, resembling blackheads.
It is not characterized by diffuse **hyperpigmentation** or the increased terminal hair growth described in this case.
Melanocytic Nevi Indian Medical PG Question 6: Patient with pigmented skin lesion shows pagetoid spread of atypical melanocytes. Diagnosis?
- A. Lentigo maligna
- B. Superficial spreading melanoma (Correct Answer)
- C. Blue nevus
- D. Nodular melanoma
Melanocytic Nevi Explanation: ### Superficial spreading melanoma
- This is the most common type of melanoma and is characterized by a **radial growth phase** where atypical melanocytes spread along the **dermo-epidermal junction** and into the epidermis (pagetoid spread) [1].
- **Pagetoid spread**, referring to the upward migration of atypical melanocytes into the spinous and granular layers of the epidermis, is a hallmark histological feature.
*Lentigo maligna*
- This is a melanoma subtype primarily affecting **chronically sun-damaged skin** in older individuals, typically on the face.
- While it has a prolonged **radial growth phase**, the atypical melanocytes tend to be confined to the **basal layer** and do not typically exhibit prominent pagetoid spread like superficial spreading melanoma.
*Blue nevus*
- A blue nevus is a **benign melanocytic lesion** characterized by the presence of dermal melanocytes that produce melanin deep within the dermis, giving it a characteristic blue or blue-gray color [2].
- It does not involve **atypical melanocytes** or **pagetoid spread** (upward migration of cells into the epidermis).
*Nodular melanoma*
- This is an aggressive subtype of melanoma characterized by a rapid **vertical growth phase** and minimal or absent radial growth phase [1].
- It presents as a **dark, raised nodule** and typically lacks the prominent pagetoid spread seen in the superficial spreading type, as its growth is primarily downward into the dermis.
**References:**
[1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Skin, pp. 1151-1152.
[2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Skin, p. 1146.
Melanocytic Nevi Indian Medical PG Question 7: What is the dermatological sign associated with carcinoma of the stomach?
- A. Palmoplantar keratoderma
- B. Acquired ichthyosis
- C. Acanthosis Nigrans (Correct Answer)
- D. Acrokeratosis paraneopiastica
Melanocytic Nevi Explanation: **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).
Melanocytic Nevi Indian Medical PG Question 8: Which of the following conditions shows susceptibility to squamous cell carcinoma in the skin?
- A. Epidermodysplasia verruciformis
- B. Actinic keratosis
- C. Xeroderma pigmentosum
- D. All the above (Correct Answer)
Melanocytic Nevi Explanation: **Explanation:**
Squamous Cell Carcinoma (SCC) of the skin is a malignant tumor of epidermal keratinocytes. Its development is often preceded by precancerous lesions or genetic conditions that impair the skin's ability to repair DNA damage or control viral oncogenesis.
* **Epidermodysplasia Verruciformis (EV):** This is a rare genetic disorder characterized by an abnormal susceptibility to **Human Papillomaviruses (HPV)**, particularly types 5 and 8. Patients develop chronic wart-like lesions that have a high propensity (30-60%) for transforming into SCC, especially on sun-exposed areas.
* **Actinic Keratosis (AK):** Also known as solar keratosis, these are considered **premalignant** lesions. They represent the earliest clinical stage of SCC in situ. Histologically, they show keratinocyte atypia; if left untreated, approximately 1-10% progress to invasive SCC.
* **Xeroderma Pigmentosum (XP):** This is an autosomal recessive disorder caused by a defect in **Nucleotide Excision Repair (NER)**. Patients cannot repair DNA damage caused by UV radiation, leading to a 10,000-fold increased risk of developing skin cancers, including SCC, Basal Cell Carcinoma (BCC), and Melanoma at a very young age.
Since all three conditions are well-documented precursors or risk factors for SCC, **Option D** is the correct answer.
**High-Yield Clinical Pearls for NEET-PG:**
* **Marjolin’s Ulcer:** SCC arising in chronic scars, non-healing ulcers, or burn sites. It is more aggressive than UV-induced SCC.
* **Bowen’s Disease:** A clinical term for SCC in situ (full-thickness atypia without basement membrane invasion).
* **Arsenic Exposure:** A systemic risk factor that typically leads to multiple SCCs on the palms and soles.
* **Most common site for SCC:** Lower lip (whereas BCC is more common on the upper lip).
Melanocytic Nevi Indian Medical PG Question 9: Which of the following lesions shows characteristic anagen, catagen, and telogen phases?
- A. Keratoacanthoma (Correct Answer)
- B. Basal cell carcinoma
- C. Leukoplakia
- D. Squamous cell carcinoma
Melanocytic Nevi Explanation: **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.
Melanocytic Nevi Indian Medical PG Question 10: A patient presents with multiple, pearly papules on the face. Biopsy reveals a malignant tumor. Which of the following microscopic features would most likely be observed?
- A. Cytoplasmic viral inclusions
- B. Keratin
- C. Melanin
- D. Palisading nuclei (Correct Answer)
Melanocytic Nevi Explanation: **Explanation:**
The clinical presentation of **pearly papules** on the face, often with telangiectasia, is the classic description of **Basal Cell Carcinoma (BCC)**, the most common skin cancer.
**Why the correct answer is right:**
The hallmark histopathological feature of BCC is the presence of nests or islands of basaloid cells (cells with large, dark nuclei and scant cytoplasm). At the periphery of these nests, the nuclei align themselves in a parallel, fence-like arrangement known as **peripheral palisading**. Additionally, a characteristic "retraction artifact" (clefting) is often seen between the tumor nests and the surrounding stroma.
**Why the incorrect options are wrong:**
* **A. Cytoplasmic viral inclusions:** These are characteristic of viral infections like Molluscum Contagiosum (Henderson-Patterson bodies) or HPV (koilocytes), not malignant tumors like BCC.
* **B. Keratin:** While BCC can occasionally show focal keratinization (Basosquamous variant), **Keratin pearls** are the pathognomonic feature of **Squamous Cell Carcinoma (SCC)**.
* **C. Melanin:** While "Pigmented BCC" exists, melanin is the defining feature of **Melanoma**. In a general question about pearly papules, palisading is the more specific diagnostic marker for BCC.
**High-Yield NEET-PG Pearls:**
* **Most common site:** Upper 2/3rd of the face (above the line joining the earlobe to the angle of the mouth).
* **Risk Factor:** Chronic UV exposure; also associated with **Gorlin Syndrome** (PTCH gene mutation).
* **Behavior:** Locally invasive ("Rodent ulcer") but rarely metastasizes.
* **Treatment of choice:** Surgical excision or Mohs Micrographic Surgery (for high-risk areas).
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