Pigmentary Disorders in Children — MCQs

10 questions

A male with hyperpigmentation tanner stage 5 presents with hypertension & precocious puberty. The causative defect is:

A patient has multiple meningiomas, acoustic neuroma and hyperpigmented skin lesions; most likely diagnosis is –

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 24-year-old male presents with a lesion at the site shown in the image for 4 years. He says it has increased in thickness over the years. Diagnosis is:

A patient presents with the skin finding shown in the image. Identify the most likely diagnosis for this lesion.

All are true about this lesion seen in a child with epilepsy except:

Lines of Blaschko are related to?

Which of the following is not true about hydroquinone?

A male patient presents with patchy loss of hair involving the scalp, eyebrows, and beard with presence of grey hair in the affected areas. What is the most likely diagnosis?

Q10Medium

A child presents with a history of hypopigmented macules on the back, infantile spasms, and delayed milestones. What is the most likely diagnosis?

Pigmentary Disorders in Children Indian Medical PG Practice Questions and MCQs

Question 1: A male with hyperpigmentation tanner stage 5 presents with hypertension & precocious puberty. The causative defect is:

A. 17 alpha hydroxylase deficiency
B. 17 beta hydroxylase deficiency
C. 11 beta hydroxylase deficiency (Correct Answer)
D. 21 beta hydroxylase deficiency

Explanation: ***11 beta hydroxylase deficiency*** - This deficiency leads to an accumulation of **11-deoxycortisol** and **deoxycorticosterone (DOC)**, a potent mineralocorticoid [1]. - **DOC excess** causes **hypertension** and **hypokalemia**, while the shunting of precursors to the androgen pathway results in **precocious puberty** in males and virilization in females, along with **hyperpigmentation** due to increased ACTH [1]. *17 alpha hydroxylase deficiency* - This deficiency impairs the synthesis of **cortisol** and **sex steroids**, leading to an accumulation of **mineralocorticoid precursors (DOC and corticosterone)**. - Patients typically present with **hypertension**, **hypokalemia**, and **absent or rudimentary secondary sexual characteristics** (delayed puberty/sexual infantilism) due to the lack of androgens/estrogens, not precocious puberty. *17 beta hydroxylase deficiency* - This enzyme is crucial for the final step in sex steroid synthesis (e.g., testosterone from androstenedione). - A deficiency would lead to **impaired sexual development** and **ambiguous genitalia or undervirilization** in males, along with delayed puberty, completely contradictory to precocious puberty. *21 beta hydroxylase deficiency* - This is the **most common cause of congenital adrenal hyperplasia (CAH)**, leading to a profound deficiency in cortisol and aldosterone, and an excess in androgens [1]. - Patients typically present with **salt-wasting crises** (due to aldosterone deficiency) or **virilization** (due to androgen excess), but usually **hypotension** (due to salt wasting) or normal blood pressure, not hypertension alongside precocious puberty in this specific manner [1].

Question 2: A patient has multiple meningiomas, acoustic neuroma and hyperpigmented skin lesions; most likely diagnosis is –

A. Neurofibromatosis (Correct Answer)
B. Von Hippel lindau disease
C. Sturge weber syndrome
D. Tuberous sclerosis

Explanation: ***Neurofibromatosis*** - The combination of **multiple meningiomas**, **acoustic neuroma** (specifically bilateral in NF2) [1], and **hyperpigmented skin lesions** (cafe-au-lait spots in NF1, or multiple cutaneous neurofibromas) is highly characteristic of neurofibromatosis. - This presentation suggests either **Neurofibromatosis type 1 (NF1)** with meningiomas (less common but possible) or, more strongly, **Neurofibromatosis type 2 (NF2)** due to the bilateral acoustic neuromas and the presence of meningiomas, with hyperpigmentation being a variable feature [1]. *Von Hippel-Lindau disease* - This disorder is characterized by **hemangioblastomas** of the retina and central nervous system, **renal cell carcinoma**, and **pheochromocytomas**. - It does not typically involve meningiomas, acoustic neuromas, or hyperpigmented skin lesions. *Sturge-Weber syndrome* - This is a neurocutaneous disorder featuring a **port-wine stain (facial nevus flammeus)**, leptomeningeal angioma, and **glaucoma**. - The clinical picture of meningiomas, acoustic neuroma, and hyperpigmented skin lesions does not align with Sturge-Weber syndrome. *Tuberous sclerosis* - This condition is characterized by the growth of numerous **benign tumors in many different organs**, including the brain (tubers, subependymal giant cell astrocytomas), skin (facial angiofibromas, shagreen patches, ash-leaf spots), kidneys (angiomyolipomas), and heart (rhabdomyomas). - While it has **skin lesions** and **brain tumors**, these are distinct from meningiomas and acoustic neuromas, which are not typical features.

Question 3: 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

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.

Question 4: A 24-year-old male presents with a lesion at the site shown in the image for 4 years. He says it has increased in thickness over the years. Diagnosis is:

A. Spitz nevus
B. Hyper-melanosis of Ito
C. Becker's nevus (Correct Answer)
D. Congenital melanocytic nevus

Explanation: ***Becker's nevus*** - This lesion typically presents as a **unilateral, hyperpigmented patch** that often appears during childhood or adolescence, increasing in size and thickness with associated **hypertrichosis** (increased hair growth). The image shows a large, irregularly shaped, hyperpigmented area on the torso of a young male, consistent with this description. - The history of increasing thickness over four years further supports **Becker's nevus**, as it is known to progress in thickness and texture, often becoming more indurated and sometimes verrucous. *Spitz nevus* - Spitz nevus is a benign melanocytic nevus typically presenting as a **pink or red, dome-shaped papule or nodule**, commonly on the face or limbs. - It rapidly grows but does not typically present as a large, hyperpigmented patch with associated hypertrichosis like the lesion shown. *Hyper-melanosis of Ito* - Hypermelanosis of Ito (also known as incontinentia pigmenti achromians) is characterized by **streaky or whorled hypopigmented (lighter) skin lesions**, often present at birth or in early infancy. - The image clearly shows a **hyperpigmented (darker) lesion**, which directly contradicts the characteristic hypopigmentation of hypermelanosis of Ito. *Congenital melanocytic nevus* - Congenital melanocytic nevi are typically present **at birth** or become apparent shortly thereafter. While they can be large and hyperpigmented, they usually do not have the prominent feature of increasing thickness and hypertrichosis developing many years later in adolescence or early adulthood in the same way as Becker's nevus. - The description of a lesion appearing during adolescence and increasing in thickness and hairiness for four years makes Becker's nevus a more specific diagnosis than a general congenital melanocytic nevus.

Question 5: A patient presents with the skin finding shown in the image. Identify the most likely diagnosis for this lesion.

A. Vitiligo
B. Contact leukoderma
C. Piebaldism (Correct Answer)
D. Albinism

Explanation: ***Piebaldism*** - The image shows a **localized patch of depigmentation** on the forehead, characteristic of **piebaldism**. - **Piebaldism** is a rare, congenital autosomal dominant disorder caused by a defect in melanocyte development and migration, resulting in stable, well-demarcated depigmented areas, often with a **white forelock**. *Vitiligo* - **Vitiligo** typically presents as **progressive, acquired macules and patches of depigmentation** that often enlarge over time. - While it can appear on the face, the sharply demarcated, congenital appearance seen here is more consistent with piebaldism. *Contact leukoderma* - **Contact leukoderma** is an **acquired depigmentation** resulting from exposure to chemicals (e.g., rubber, phenols). - It would usually present in areas of direct contact, and the congenital nature of the lesion in the image rules this out. *Albinism* - **Albinism** is a **generalized hypopigmentation** affecting the skin, hair, and eyes due to a defect in melanin production. - The image shows a localized patch of depigmentation, not a widespread lack of pigment characteristic of albinism.

Question 6: All are true about this lesion seen in a child with epilepsy except:

A. Collagenoma
B. Minor criteria for diagnosis (Correct Answer)
C. Peau d'orange appearance
D. Predominantly seen over trunk

Explanation: ***Minor criteria for diagnosis*** - The presented lesion is a **Shagreen patch**, which is considered a **major diagnostic criterion** for **Tuberous Sclerosis Complex (TSC)**, not a minor one. - A definitive diagnosis of TSC requires two major criteria or one major and two minor criteria. *Collagenoma* - A Shagreen patch is a type of dermal **collagenoma**, characterized by an overgrowth of connective tissue, primarily collagen. - These lesions often feel like **roughened or leathery plaques** on the skin. *Peau d'orange appearance* - The Shagreen patch is often described as having a **'peau d'orange'** or orange peel-like texture due to its irregular surface. - This characteristic texture helps in its clinical identification. *Predominantly seen over trunk* - Shagreen patches are typically located on the **trunk**, especially in the lumbosacral region, as seen in the image. - They are one of the distinctive cutaneous manifestations of TSC.

Question 7: Lines of Blaschko are related to?

A. Keratinocytes (Correct Answer)
B. Blood vessels
C. Nerves
D. Bones

Explanation: ***Keratinocytes*** - **Lines of Blaschko** represent the migratory pathways of embryonic cells, primarily **keratinocytes**, in the skin. - These lines are not visible under normal conditions but become apparent in various **genetic skin disorders** where abnormal cells follow these specific patterns. *Blood vessels* - While blood vessels are extensively present in the skin, they do not follow the specific **migratory patterns** described by the Lines of Blaschko. - Their arrangement is more related to **vascular networks** and anatomical supply rather than embryonic cell migration. *Nerves* - **Nerves** in the skin have specific distributions, often following dermatomal patterns, which are distinct from the **Lines of Blaschko**. - Nerve distribution is related to their segmental origin from the **spinal cord**, not the migratory paths of epidermal cells. *Bones* - **Bones** are part of the skeletal system and are not found in the skin, making them unrelated to the **Lines of Blaschko**. - These lines describe epidermal cell migration, which is a feature of the **integumentary system**.

Question 8: Which of the following is not true about hydroquinone?

A. Response is incomplete and pigmentation may recur
B. It inhibits tyrosinase
C. It requires prescription strength concentrations above 2%
D. It should not be used for melasma or chloasma of pregnancy (Correct Answer)

Explanation: ***It should not be used for melasma or chloasma of pregnancy*** - This statement is **NOT TRUE** - hydroquinone is actually a **first-line treatment for melasma** including chloasma (melasma of pregnancy) - Hydroquinone 2-4% is one of the **most effective topical agents** for treating melasma and is widely recommended in dermatological guidelines - While hydroquinone use during **active pregnancy** is approached with caution (FDA Category C), it is definitely indicated for treating melasma/chloasma **after pregnancy** and for general melasma in non-pregnant patients - The condition (melasma/chloasma) is appropriately treated with hydroquinone; only the **timing during pregnancy** requires consideration *Response is incomplete and pigmentation may recur* - This is a **TRUE statement** about hydroquinone therapy - Treatment response is often **incomplete** with partial lightening of hyperpigmentation - **Recurrence is common** after discontinuation, especially with continued sun exposure or hormonal triggers - Maintenance therapy is often needed to sustain results *It inhibits tyrosinase* - This is a **TRUE statement** - hydroquinone's primary mechanism of action - Acts as a **competitive inhibitor of tyrosinase**, the rate-limiting enzyme in melanin synthesis - This inhibition reduces melanin production in melanocytes, leading to depigmentation *It requires prescription strength concentrations above 2%* - This is a **TRUE statement** in most countries including India and the USA - Hydroquinone concentrations **≤2%** are available over-the-counter (OTC) - Concentrations **>2% (typically 3-4%)** require a prescription - Higher concentrations provide greater efficacy but also increased risk of side effects like ochronosis

Question 9: A male patient presents with patchy loss of hair involving the scalp, eyebrows, and beard with presence of grey hair in the affected areas. What is the most likely diagnosis?

A. Androgenic alopecia
B. Anagen effluvium
C. Alopecia areata (Correct Answer)
D. Telogen effluvium

Explanation: ***Alopecia areata*** - This condition is characterized by **patchy hair loss** that can affect the scalp, eyebrows, and beard, and is often associated with the presence of **grey hairs** in the affected areas. - It is an **autoimmune disorder** where the immune system mistakenly attacks **hair follicles**, leading to non-scarring hair loss. *Androgenic alopecia* - This is commonly known as **male-pattern baldness** and typically presents as a receding hairline and thinning at the crown. - It is primarily driven by **genetics** and **androgen hormones**, and does not usually involve patchy loss or affect eyebrows and beard in the same way. *Anagen effluvium* - This condition is often caused by **chemotherapy** or other strong chemical exposures, leading to an abrupt and widespread loss of hair during the **anagen (growth) phase**. - Hair loss is typically diffuse and rapid, not usually localized to patches or accompanied by grey hair in specific areas. *Telogen effluvium* - This is a common form of **temporary hair loss** that occurs following a stressful event, fever, childbirth, or severe illness, causing premature shedding of hairs in the **telogen (resting) phase**. - It results in diffuse thinning rather than discrete patchy hair loss and is not typically associated with grey hair in the manner described.

Question 10: A child presents with a history of hypopigmented macules on the back, infantile spasms, and delayed milestones. What is the most likely diagnosis?

A. Neurofibromatosis
B. Sturge-Weber syndrome
C. Tuberous sclerosis (Correct Answer)
D. Nevus anemicus

Explanation: ### Explanation **Correct Answer: C. Tuberous Sclerosis (TSC)** The clinical triad of **hypopigmented macules (Ash-leaf spots)**, **infantile spasms** (West Syndrome), and **delayed milestones** is classic for Tuberous Sclerosis Complex. * **Pathophysiology:** TSC is an autosomal dominant neurocutaneous syndrome caused by mutations in the *TSC1* (Hamartin) or *TSC2* (Tuberin) genes, leading to the overactivation of the mTOR pathway and the formation of hamartomas in multiple organs. * **Dermatological markers:** Ash-leaf spots are often the earliest sign. Other features include Adenoma sebaceum (angiofibromas), Shagreen patches (connective tissue nevi), and periungual fibromas (Koenen tumors). * **Neurological markers:** Cortical tubers and subependymal nodules lead to seizures (infantile spasms) and intellectual disability. **Why Incorrect Options are Wrong:** * **A. Neurofibromatosis:** Characterized by *hyperpigmented* Café-au-lait macules, Lisch nodules, and neurofibromas, rather than hypopigmentation and infantile spasms. * **B. Sturge-Weber Syndrome:** Presents with a Port-wine stain (Nevus Flammeus) in the V1/V2 distribution of the trigeminal nerve, glaucoma, and leptomeningeal angiomas. * **C. Nevus Anemicus:** A localized vascular anomaly presenting as a pale patch due to catecholamine sensitivity. It does not cause systemic neurological symptoms or developmental delay. **High-Yield Clinical Pearls for NEET-PG:** * **Earliest sign:** Ash-leaf spots (best seen under **Wood’s lamp**). * **Most common heart lesion:** Rhabdomyoma (often regresses spontaneously). * **Most common kidney lesion:** Angiomyolipoma. * **Drug of choice for Infantile Spasms in TSC:** Vigabatrin. * **Pathognomonic sign:** Koenen tumors (Periungual fibromas).

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