DermaDiagnosis
When You Can’t Make a Rash Diagnosis
The itchy rash surrounding this 64-year-old man's head and neck has persisted for years without a clear diagnosis. Recently, he noticed lumps...
ANSWER
The correct answer is Becker nevus (BN; choice “c”).
Because the lesion was not congenital, a number of possibilities, including congenital melanocytic nevus (choice “a”), were ruled out. Another differential item that was eliminated was nevus spilus (choice “b”), a tan congenital nevus covered with darker, punctate macules that usually manifest on extremities. These have little, if any, malignant potential.
And while BN is not associated with malignancy, it is possible for it to co-exist with melanoma (choice “d”). Therefore, atypical BN cases may need to be followed or serially biopsied.
DISCUSSION
BN is unusual but not rare. Also referred to as Becker melanosis, the condition affects approximately 0.5% of the population. It primarily manifests in young men during early puberty, although women can develop BN.
Histologic signs of BN include epidermal thickening, elongation of rete ridges, and increased bundles of smooth muscle in the dermis.
Androgen causation is strongly indicated by the condition’s predominance in males and onset at puberty, as well as its associated hypertrichosis and increased density of androgen receptors in affected areas. Variations of the condition can involve the legs, arms, or face. It is possible for BN to manifest without additional hair growth. Hypoplasia of ipsilateral pectoral structures (or the ipsilateral breast in women) has also been reported.
Several types of lasers can be used to lighten the hyperpigmentation and remove hairs. This treatment modality yields variable results.
