What is the cause of his pigmented lesion?

A 63-year-old male was recommended to have a pigmented lesion behind his ear checked out. It was asymptomatic and of unknown duration; in fact, he was unaware of it. 

What could be the cause?

A.  Malignant melanoma.

B.  Seborrheic keratoses.

C.  Compound nevus.

D.  Dysplastic nevus.

E.  Linear epidermal nevus.

(Answer and discussion on next page)

Answer—Malignant melanoma

A biopsy revealed a 0.89 mm malignant melanoma. Melanomas <1 mm in thickness do not require lymph node biopsy as it has not been shown to affect life expectancy. Sentinel node biopsy remains an area of controversy. It can provide prognostic information in clinical trials, but is of questionable benefit in the typical clinical setting.