How do you explain this asymmetric hair growth?

Dermclinic
A Photo Quiz to Hone Dermatologic Skills

Case 4:
Asymmetric hair growth is noted on the back of a 25-year-old man when he seeks treatment of severe sunburn. The patient first noticed this pattern 7 or 8 years earlier.

What do you suspect?

A. Hirsutism.
B. Hypertrichosis.
C. Congenital melanocytic nevus.
D. Becker nevus.
E. Normal anatomic variation.

(Answer on next page.)

Dermclinic—Answer

Case 4: Becker nevus

This patient had a Becker nevus, D, a smooth muscle hamartoma that appears to be under hormonal influence because it occurs after puberty. Reassurance is the only treatment necessary for these benign lesions.

Hirsutism manifests mainly in women as unwanted hair in a male distribution; hypertrichosis refers to an overgrowth of hair or the development of hair in areas where it is usually not found. Unlike Becker nevi, which may have a café-au-lait background, congenital melanocytic nevi have a pigmented background.   ■