Pigmentary Disorders — MCQs
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Which of the following disorders is least commonly associated with vitiligo?
Lesions of Nevus of Ota commonly involve which cranial nerve?
Ash leaf maculae are characteristic of which condition?
Café au lait spots are seen in which condition?
Pigmentary Disorders Indian Medical PG Practice Questions and MCQs
Question 121: Which of the following disorders is least commonly associated with vitiligo?
- A. Graves' disease
- B. Addison's disease
- C. Alopecia areata
- D. Nelson's syndrome (Correct Answer)
Explanation: ***Nelson's syndrome*** - **Nelson's syndrome** is a condition that occurs after bilateral adrenalectomy for **Cushing's disease** and is characterized by a rapidly growing pituitary adenoma, hyperpigmentation, and neurological symptoms. It is not an autoimmune disorder and has **no known association with vitiligo**. - Vitiligo is an **autoimmune disorder** where the immune system destroys melanocytes, leading to patches of skin depigmentation. Its strongest associations are with other autoimmune conditions. *Alopecia areata* - **Alopecia areata** is an autoimmune disease causing non-scarring hair loss in patches. - It is a well-established **autoimmune comorbidity of vitiligo**, often found in the same patients due to shared autoimmune mechanisms. *Graves' disease* - **Graves' disease** is an autoimmune disorder that causes hyperthyroidism, characterized by overproduction of thyroid hormones. - It is a common autoimmune disease strongly associated with vitiligo, as both conditions often occur together due to a predisposition to **autoimmunity**. *Addison's disease* - **Addison's disease** is an autoimmune disorder leading to primary adrenal insufficiency, where the adrenal glands produce insufficient steroid hormones. - There is a significant association between Addison's disease and vitiligo, and concurrent occurrence is common as part of **autoimmune polyendocrine syndromes**.
Question 122: Lesions of Nevus of Ota commonly involve which cranial nerve?
- A. Oculomotor nerve (Cranial Nerve III)
- B. Trigeminal nerve (Cranial Nerve V) (Correct Answer)
- C. Spinal accessory nerve (Cranial Nerve XI)
- D. Facial nerve (Cranial Nerve VII)
Explanation: ***Trigeminal nerve (Cranial Nerve V)*** - Nevus of Ota is a **dermal melanocytosis** typically presenting as bluish-gray patches on the face, specifically within the distribution of the **ophthalmic (V1)** and **maxillary (V2) divisions** of the trigeminal nerve. - The lesions often involve the **periorbital region**, forehead, and cheek, corresponding to the sensory innervation fields of these trigeminal nerve branches. *Oculomotor nerve (Cranial Nerve III)* - The oculomotor nerve primarily controls **eye movements** and **pupil constriction**. - While Nevus of Ota can occasionally involve the eye itself (e.g., episcleral melanocytosis), its cutaneous lesions are not distributed along the oculomotor nerve's innervation pattern. *Spinal accessory nerve (Cranial Nerve XI)* - The spinal accessory nerve is a **motor nerve** responsible for controlling the **sternocleidomastoid** and **trapezius muscles**. - It has no sensory or cutaneous distribution relevant to the facial lesions seen in Nevus of Ota. *Facial nerve (Cranial Nerve VII)* - The facial nerve primarily controls **facial expressions** and taste sensation from the anterior two-thirds of the tongue. - Although it innervates facial muscles, its cutaneous sensory distribution is minimal, and the characteristic skin lesions of Nevus of Ota do not follow its pattern.
Question 123: Ash leaf maculae are characteristic of which condition?
- A. Tuberous sclerosis (Correct Answer)
- B. Lymphangioma
- C. Neurofibromatosis
- D. None of the options
Explanation: ***Tuberous sclerosis*** - **Ash leaf macules** are hypomelanotic macules, typically shaped like an ash leaf, which are a hallmark dermatological finding in **tuberous sclerosis complex (TSC)**. - TSC is a **neurocutaneous syndrome** characterized by the formation of benign tumors in various organs, including the brain, skin, kidneys, and heart. *Lymphangioma* - A **lymphangioma** is a benign malformation of the lymphatic system, typically presenting as a soft, compressible, subcutaneous mass. - It does not involve **hypopigmented macules** or other characteristic features of TSC. *Neurofibromatosis* - **Neurofibromatosis** is associated with **café-au-lait spots**, which are hyperpigmented patches, and **neurofibromas**, not hypopigmented ash leaf macules. - While also a neurocutaneous disorder, its skin manifestations are distinct from those of tuberous sclerosis. *None of the options* - This option is incorrect because **tuberous sclerosis** is directly characterized by ash leaf macules, making it the correct diagnosis. - The presence of ash leaf macules is a highly specific clue pointing to TSC.
Question 124: Café au lait spots are seen in which condition?
- A. Cockayne syndrome
- B. Down syndrome
- C. Neurofibromatosis (Correct Answer)
- D. Gardner's syndrome
Explanation: ***Neurofibromatosis*** - **Café au lait spots** (light brown macules) are a hallmark feature of **Neurofibromatosis type 1 (NF1)**, often appearing in childhood. - Diagnosis of NF1 usually requires having **six or more café au lait spots** larger than 5 mm in prepubertal children or 15 mm in postpubertal individuals. *Cockayne syndrome* - This is a rare genetic disorder characterized by **premature aging**, **photosensitivity**, and **neurological dysfunction**, but not café au lait spots. - Key features include **dwarfism**, a "bird-like" facial appearance, and **progressive neurological degeneration**. *Down syndrome* - Caused by trisomy of chromosome 21, **Down syndrome** presents with distinct facial features like an upward slant to the eyes and a single palmar crease. - While it can be associated with various medical conditions, **café au lait spots** are not a characteristic finding. *Gardner's syndrome* - This is a subtype of **familial adenomatous polyposis** characterized by numerous **colorectal polyps**, alongside extracolonic manifestations such as **osteomas** and **desmoid tumors**. - **Pigmented lesions** can occur, but these are typically **retinal pigmented epithelial hypertrophy** or epidermal cysts, rather than café au lait spots.
Practice by Chapter
Melanocyte Biology
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Vitiligo
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Melasma
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Post-inflammatory Hyperpigmentation
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Post-inflammatory Hypopigmentation
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Albinism
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Drug-Induced Pigmentary Changes
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Pityriasis Alba
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Pigmentary Demarcation Lines
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Nevi of Ota and Ito
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Management of Hyperpigmentation
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Management of Hypopigmentation
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