ABD Pigmentary Disorders 3

Question 1

Incontinentia pigmenti (Bloch-Sulzberger syndrome) progresses through four cutaneous stages in which order?

Accepted Answer

Vesicles/bullae → verrucous → whorled hyperpigmentation (Blaschko's lines) → hypopigmented/atrophic

Answer

Hyperpigmentation → vesicles → verrucous → hypopigmentation

Answer

Pustules → erosions → scarring → hyperpigmentation

Answer

Erythema → blistering → atrophy → hyperpigmentation

Question 2

Which constellation of findings is diagnostic of Waardenburg syndrome?

Accepted Answer

Sensorineural deafness, white forelock, heterochromia iridis, and dystopia canthorum

Answer

Sensorineural deafness, diffuse hyperpigmented patches, blue nevi, and café-au-lait spots

Answer

Ash-leaf macules, seizures, hypopigmented patches, and cardiac rhabdomyomas

Answer

Poliosis, vitiligo, uveitis, and aseptic meningitis

Question 3

In a fair-skinned infant suspected of having tuberous sclerosis complex, ash-leaf macules are best detected using:

Accepted Answer

Wood's lamp examination in a darkened room

Answer

High-resolution dermoscopy

Answer

Confocal reflectance microscopy

Answer

Diascopy to assess blanching

Question 4

Erythema dyschromicum perstans (ashy dermatosis) is best characterized by which description?

Accepted Answer

Gray-brown ('ashy') macules and patches with active erythematous borders in early stages, predominantly affecting individuals with darker phototypes

Answer

Erythematous plaques that resolve without leaving pigmentary change

Answer

Reticulate hyperpigmentation in chronic sun-exposed areas with poikiloderma

Answer

Linear hyperpigmented streaks following sites of skin trauma (Koebnerization)

Question 5

Perioral and acral mucocutaneous lentigines in Peutz-Jeghers syndrome result from germline mutations in which gene?

Accepted Answer

STK11/LKB1 (serine-threonine kinase 11) on chromosome 19p

Answer

PTEN (phosphatase and tensin homolog) on chromosome 10q

Answer

BRAF (v-raf murine sarcoma viral oncogene homolog B1)

Answer

RET proto-oncogene on chromosome 10q11

Question 6

Dyschromatosis symmetrica hereditaria, featuring a mixture of hyper- and hypopigmented macules on the dorsal hands and feet, is most commonly caused by autosomal dominant mutations in:

Accepted Answer

ADAR1 (adenosine deaminase acting on RNA)

Answer

TYR (tyrosinase)

Answer

KIT (c-kit proto-oncogene receptor tyrosine kinase)

Answer

EDNRB (endothelin receptor type B)

Question 7

Becker's nevus (Becker's melanosis) is best classified as:

Accepted Answer

An organoid hamartoma with androgen-sensitive smooth muscle, presenting as hyperpigmented hypertrichotic patch on the shoulder of adolescent males

Answer

A melanocytic nevus with significant malignant transformation potential

Answer

A congenital dermal melanocytosis similar to Mongolian spot

Answer

A vascular malformation with overlying epidermal hyperpigmentation