Granuloma annulare restricted to Becker's naevus

Sebaceus and Becker's Nevus: Overview of Their Presentation, Pathogenesis, Associations, and Treatment

Nevus sebaceus (NS) and Becker's nevus (BN) are two variants of epidermal nevi. NS clinically presents as a yellowish-orange, hairless plaque on the scalp, face, or neck, while BN presents as a tan-to-brown hyperpigmented, sometimes hypertrichotic, plaque typically on the chest and shoulder. Histologically, NS displays mature or nearly mature sebaceus glands as well as acanthosis and fibroplasia of the papillary dermis. BN shows variable papillomatosis, acanthosis, and hyperkeratosis, with hyperpigmentation of the basal/suprabasal layer. While the genetic basis of NS is thought to be due to post-zygotic mutations in the Harvey rat sarcoma viral oncogene homolog (HRAS)/Kristen rat sarcoma viral oncogene homolog (KRAS) genes, the genetic basis of BN is relatively unknown and is implicated with paradominant inheritance. In some patients, NS and BN can each be associated with additional cutaneous and extra-cutaneous anomalies, ranging from benign or malignant tumors to multiple organ irregularities. Due to the wide range of possible associations, treatment for NS and BN is devised on a case-by-case basis. In this article, we review the features, etiology, and diagnosis/management of NS and BN, with a focus on associations. We also report a patient who concomitantly presents with both lesions.

Becker nevus on the lower limb: case report and review of the literature

BACKGROUND

Becker nevus is a hamartoma with brown hyperpigmentation and hypertrichosis that usually affects young males. It has a predilection for the upper half of the trunk and proximal upper extremity.

OBJECTIVE

This is a case report of a 38-year-old male with a Becker nevus without hypertrichosis on the lower limb and a review of the literature.

RESULTS

Including our case report, 12 cases of Becker nevus on the lower limb were identified in the English literature (8 males and 4 females). It has never been reported below the knee. In males, the lesion was not associated with other anomalies, and all but two showed hypertrichosis (six of eight). In 50% (two of four) of women, it was associated with localized lipoatrophy. In one woman, it presented without hypertrichosis.

CONCLUSION

The presence of Becker nevi on the lower limb is unusual, and hypertrichosis is not always a feature. Larger studies are required to look into the true prevalence of this presentation and its prognostic value as a marker for other anomalies.

ILVEN-like persistent psoriasiform dermatitis confined to a congenital Becker nevus

A 10-year-old boy presented with a 5-year history of an intractably pruritic, recalcitrant psoriasiform plaque in a broad vertical band on the left buttock, with histologic as well as clinical features suggestive of an inflammatory linear verrucous epidermal nevus. This lesion was completely superimposed upon a congenital Becker nevus. We postulate that the restricted distribution and persistence of the psoriasiform plaque reflected an inflammatory response limited to the aberrant clone of cells composing the Becker nevus, a manifestation of cutaneous mosaicism that could be characterized as an "inflammatory Becker nevus."