Congenital self-healing reticulohistiocytosis: report of a patient with a strikingly large tumor mass.

A newborn male Thai infant had numerous brownish red nodules of various sizes scattered over both palms and soles, left thigh, abdomen, chin, and left upper eyelid. An extremely large tumor mass was present on the right sole. Many lesions showed spontaneous ulceration. No extracutaneous involvement was found. All lesions involuted spontaneously within two to three months, some with scar formation. Histology showed large numbers of mononucleated and multinucleated histiocytic cell infiltrations, 10% of which contained Birbeck's granules. Areas of necrosis and calcification were also seen in the largest tumor. No recurrence was observed after follow-up for three years.