PIGMENTED DERMATOFIBROSARCOMA PROTUBERANS (BEDNAR TUMOR) OCCURRING INA JAPANESE INFANT

A case of pigmented dermatofibrosarcoma protuberans (Bednar tumor) occ urring in a Japanese infant is reported. A 6-month-old girl developed a 16 x 10 mm erythematous tumor with a slight elevation on the lower b ack at 1 month of age. Histological examination revealed proliferation of spindle-shaped, fibroblast-like cells in the myxoid interstitium. Subsequently the tumor grew gradually to a red-purplish tumor measurin g 45 x 36 mm. The second biopsy specimen presented hypercellular proli feration composed of spindle-shaped cells showing slight nuclear atypi a and a characteristic storiform pattern, with scattered slender dendr itic cells containing a large amount of brown pigment. Immunohistochem ical studies of the second biopsy specimen showed that the spindle-sha ped tumor cells were positive for vimentin and CD34 and negative for f actor XIIIa. The number of CD34-reactive spindle-shaped tumor cells in creased in the second biopsy specimen compared with the first biopsy.