Localized cluster of nodules in childhood

Abstract

An 8-year-old girl presented with multiple, asymptomatic skin lesions localized to her right lower abdomen. These had first appeared 6 years previously, and had gradually increased in number over the intervening years. The patient was otherwise systemically well. On physical examination, a plaque 50 mm in size was found on the patient's right abdomen, made up of coalescing, firm, red-brown papules and nodules ranging from 4 to 10 mm in size (Fig. 1).Laboratory investigations gave normal results for full blood count, urea and electrolytes, liver function tests and protein electrophoresis. However, autoantibody screen revealed a positive titre of anti-smooth muscle antibodies (anti-SMA) (≥ 1 : 320); the rest of the autoantibody screen was negative. Histopathological findingsA punch biopsy was taken from one of the lesions, and histological examination revealed an unencapsulated dermal proliferation comprising of bland spindleshaped cells associated with collagen and scattered histiocytes (Fig. 2). Occasional foci of rounding off of collagen were noted at the periphery of the lesion. There was irregular acanthosis of the epidermis, with no increase in basal pigmentation or trichoblastic induction. The spindle-shaped cells stained positively for Factor XIIIa and negatively for CD34, SMA, desmin, CD99 and S-100P. CD34 and SMA highlighted the stroma around the proliferation and the blood vessels.What is your diagnosis? DiagnosisMultiple clustered dermatofibromas (MCDF).