A Case of Dowling-Degos Disease on the Vulva

Abstract

Dowling-Degos disease (DDD) is an autosomal dominant genodermatosis and this disease is a genetically determined disturbance of epidermal proliferation. It is characterized by acquired, slowly progressive pigmented lesions that primarily involve the great skin folds and flexural areas such as the axilla, neck, limb flexures, the inframammary area and the inguinal folds. The vulva is an unusual location for DDD. A 41-year-old woman presented with a 10-year history of multiple, small, reticulated and brownish macules distributed symmetrically on the bilateral external genital regions. We found no other similarly pigmented skin lesions on her body, including the flexural areas. There was no known family history of similar eruptions or pigmentary changes. The histologic examination showed irregular rete ridge elongation with a filiform or antler-like pattern and basilar hyperpigmentation on the tips. Fontana-Masson staining showed increased pigmentation of the rete ridges and the S100 protein staining did not reveal an increased number of melanocytes in the epidermis. From these findings, we diagnosed this lesion as DDD.

Dowling‐Degos disease with diffuse penile pigmentation

“…S100 protein staining reveals no increase in the number of melanocytes, therefore the pigmentation is not due to an increased density of melanocytes. [1][2][3] The histologic examination of our patient revealed similar findings.…”

“…Antecubital and popliteal fossae are less commonly affected, but specific genital involvement is very unusual. 2,3 Involvement of the vulva has rarely been reported, and only in one patient whose clinical spectrum is a mixture of different forms of reticulate disorders, penile involvement confined to the prepuce and corona has been reported. 4 However, to our knowledge there was no previous report of DDD with diffuse penile involvement.…”

“…5 KRT5 is known to be important in cell adhesion, the transport and transfer of melanosomes and possibly for the follicle development. [1][2][3]6 Recently, Li et al demonstrated that mutations in POFUT1, encoding protein O-fucosyltransferase 1, also caused generalized DDD. 7 The histopathologic findings of DDD are specific and well documented.…”

“…The involvement of the infundibulum of the hair follicle is a unique and distinctive feature of the reticular pigmented anomaly and not seen in seborrheic keratosis, epidermal nevus or any other lesions. 3,6 RAK is an autosomal dominantly inherited disease characterized by hyperpigmented atrophic macules on the backs of the hands and feet. The lesions worsen with sun exposure.…”

“…Clinical picture resembles DDD, but in histopathology there are foci of acantholysis. 1,3,8 However, there are some reports indicating that similar mutations of KRT5 caused both Galli-Galli disease and DDD. Therefore, Galli-Galli disease may be regarded as a variant of DDD.…”