Case of isolated benign primary cutaneous plasmacytosis in a child.

A collection of plasma cells in the skin can represent a broad spectrum of disease entities. Secondary syphilis, primary cutaneous plasmacytoma, primary cutaneous plasmacytosis, cutaneous lymphoid hyperplasia and nodular amyloidosis are considered possible differential diagnoses. We present a case of a 7-year-old girl with an erythematous scaly plaque on her right buttock that had been present for approximately 5 years. Prior to her visit to our department she had been treated at a local dermatology clinic with topical methylprednisolone acetate and topical calcitriol without significant improvement. Histopathological examination revealed psoriasiform hyperplasia, hyperkeratosis, parakeratosis and a band-like or dense perivascular infiltration of plasma cells with a few lymphocytes and histiocytes. Other laboratory tests were within the reference ranges. At our department, the patient was given oral prednisolone along with an intralesional injection of triamcinolone and application of topical methylprednisolone acetate and tacrolimus hydrate to the affected area. The lesion improved significantly but recurred 3 months later. We present a rare case of isolated benign primary cutaneous plasmacytosis in a female pre-adolescent child.