MS - Path (Miscellaneous skin disorders)

Question 1

What defines acanthosis nigricans? Where on the body is it especially found?

Answer 1

Epidermal hyperplasia causing symmetrical, hyperpigmented, velvety thickening of skin, especially on neck and axilla

Question 2

What are 2 conditions with which acanthosis nigricans is associated? Give at least one example of each of these conditions.

Answer 2

Associated with hyperinsulinemia (e.g., diabetes, obesity, Cushing syndrome) and visceral malignancy (e.g., gastric adenocarcinoma)

Question 3

What defines actinic keratosis, including its cause and appearance?

Answer 3

Premalignant lesions caused by sun exposure. Small, rough, erythematous or brownish papules or plaques

Question 4

Describe the relation of actinic keratosis to cancer and its determining factor.

Answer 4

Premalignant lesion; Risk of squamous cell carcinoma is proportional to degree of epithelial dysplasia

Question 5

What defines erythema nodosum, and where on the body does it usually occur?

Answer 5

Painful inflammatory lesions of subcutaneous fat, usually on anterior shins

Question 6

What is often the etiology of erythema nodosum? What are 7 other conditions with which it is associated?

Answer 6

Often idiopathic, but can associated with sarcoidosis, coccidioidomycosis, histoplasmosis, TB, streptococcal infections, leprosy, and Crohn disease

Question 7

What defines Lichen Planus?

Answer 7

Pruritic, Purple, Polygonal Planar Papules and Plaques are the “6 P’s of lichen Planus”

Question 8

How does mucosal involvement of Lichen Planus manifest?

Answer 8

Mucosal involvement manifests as Wickham striae (reticular white lines)

Question 9

What is the key histologic finding of Lichen Planus?

Answer 9

Sawtooth infiltrate of lymphocytes at dermal-epidermal junction

Question 10

With what condition is Lichen Planus associated?

Answer 10

Associated with hepatitis C

Question 11

What sequence and findings characterizes Pityriasis rosea?

Answer 11

“Herald patch” followed days later by “Christmas tree” distribution. Multiple plaques with collarette scale. Self-resolving in 6-8 weeks.

Question 12

What defines sunburn? What is its pathophysiology?

Answer 12

Acute cutaneous inflammatory reaction due to excessive UV irradiation. Causes DNA mutations, inducing apoptosis of keratinocytes.

Question 13

In what context(s) is UVA versus UVB irradiation dominant?

Answer 13

UVA dominant in tanning and photoaging, UVB in sunburn

Question 14

What are 2 conditions to which sunburn can lead?

Answer 14

Can lead to impetigo and skin cancers (basal cell carcinoma, squamous cell carcinoma, and melanoma)