Case notes
Over a 6-year period, a 62-year-old woman experienced asymptomatic progressive pigmentation of the vulva and perianal skin. She had been diagnosed with breast cancer in 2007 and was treated with surgery, adjuvant radiotherapy, and chemotherapy. To date, she has been in complete remission. Her family history did not include melanoma or periorificial lentiginosis.
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Physical examination revealed reticulated and confluent pigmentation of perianal, perineal, and vulvar skin, affecting the labia majora and minora ( Figure 1 ). Small, soft, dark-brown papules had developed in all of these areas ( Figure 2 ). Both axillary flexures were thickened and marked by light-brown pigmentation, with a reticulated pattern. The oral mucosa was not affected.
A biopsy specimen was taken, and histopathological analysis identified filiform elongation of epidermal rete ridges with prominent pigmentation of basal keratinocytes. There was no apparent increase in melanocytes.
Conclusions
The patient received a diagnosis of Dowling-Degos disease, a rare, benign, inherited skin disorder. Its pathogenesis, although still unknown, may be related to mutations in the keratin-5 gene (chromosome 12q) and subsequent loss of that gene’s function.
Clinically, patients present with a slowly progressive reticulated pigmentation of the flexures. Genital skin is very rarely involved, with only 4 previous cases reported. While the lesions are generally asymptomatic, some patients have reported pruritus. Clinical and histopathological features allow Dowling-Degos to be distinguished from other ailments in the differential diagnosis. These include acanthosis nigricans, vulvar melanoma, and other genodermatoses, such as Galli-Galli disease (an acantholytic variant of Dowling-Degos), reticulate acropigmentation of Kitamura, and Peutz-Jeghers syndrome.
Treatment with topical retinoids, hydroquinone, and corticosteroids has been tried but outcomes have been unsatisfactory. Recently, use of ablative erbium yttrium-aluminum-garnet laser has been reported to provide a good clinical result. Our patient decided not to receive any treatment for her hyperpigmented lesions.
The authors report no conflict of interest.
Cite this article as: Zarzoso I, Bodet D, García-Patos V. A peculiar inheritance: the patient had a net-like pattern of pigmentation on her vulva and perianal skin. Am J Obstet Gynecol 2013;208:506.e1-2.
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