Giant inguinal and suprapubic mastocytomas in an adult with a history of childhood mastocytosis

Sir, We describe a 29‐year‐old patient with systemic mastocytosis who developed inguinopubic lesions. The pathological analysis was of mastocytoma. A 29‐year‐old man, with cutaneous mastocytosis diagnosed in childhood and confirmed by various cutaneous biopsies, presented with three hard papillomatous verrucous lesions (Fig. 1a) arising from the suprapubic area and encroaching on the base of the penis and the inguinal fold. The largest lesion measured approximately 7 × 6 cm, had grown slowly but progressively over the previous 5 years from a brownish flat plaque, and was lighter in colour than the surrounding skin. The normal skin showed oval reddish urticarial papules and plaques, except for the palms of the hands, the soles of the feet, and flexures (Fig. 1b). The patient denied any sexual activity and was taking no medication. Full blood count, blood film, coagulation tests and blood chemistry were within normal limits except for IgM (392 mg dL−1, normal 53–334) and C‐reactive protein (18·5 mg L−1, normal 0–12). Urine chemistry showed elevations of dopamine (448 µg in 24 h, normal 65–400) and vanillylmandelic acid (14·6 mg in 24 h, normal < 9). Excision of the smallest lesion was done under local anaesthetic. When the incision was made, rapid hardening of the skin occurred with severe diffuse bleeding. Histological analysis showed epidermal acanthosis and papillomatosis, and a dense nodular infiltrate in the dermis made up of mast cells with ovoid nuclei, slightly granular cytoplasm, and metachromasia as demonstrated with toluidine blue staining (Fig. 1c). The second lesion was removed under spinal anaesthesia and the histological findings were the same. As the patient had been unsupervised for several years, further examination was carried out, after removal of the lesions, in order to determine any systemic involvement. A combination of osteopenic, lytic and sclerotic changes was seen in the left humerus and left costal arch, suggesting systemic mastocytosis. A bone scan with 99mTc‐dimethylphosphonate confirmed these changes. Biopsy of the bone marrow confirmed the presence of infiltration by mature mastocytes.