Palmar-plantar fibromatosis in children and preadolescents: a clinicopathologic study of 56 cases with newly recognized demographics and extended follow-up information.

Palmar-plantar fibromatosis, the most common type of fibromatosis, is well recognized in the adult population, but many clinicians and pathologists are unfamiliar with the fact that children may also be affected by this process. This report describes the clinicopathologic findings in 56 cases of palmar-plantar fibromatosis in children and preadolescents. Our study group included 19 males and 37 females, ranging from 2 to 12 years of age at the time of their first surgical procedure (median age, 9 years). The patients typically presented with solitary, lobular or multilobular masses in the 0.5- to 2.5-cm size range. The preoperative duration of the lesions ranged from 1 month to 6 years, with 1 patient purportedly having clinical evidence of disease since birth. All but two of the initial lesions occurred on the plantar aspect of the feet, typically in the region of the arch. Only 2 patients presented with palmar disease. The tumors were usually painless, except when pressure was applied. Seven patients had a history of trauma, sometimes involving a foreign body. One patient presented with concurrent disease involving both feet, and 12 additional patients subsequently developed palmar-plantar fibromatosis in another extremity, knuckle pads on the hands, or had other clinical findings linked to this disease. A family history was available for 25 patients, and 11 individuals had relatives with palmar-plantar fibromatosis, and 4 others had relatives with a history that was either suspicious for palmar-plantar disease or positive for other disorders associated with this disease. Histologically, the tumors involved aponeurosis and commonly formed discontinuous, moderately cellular, nodular masses composed of spindled cells with intervening collagen. Mitotic counts for 79 separately submitted tumor specimens ranged from 0 to 31 mitotic figures per 25 wide-field high power fields (mean mitotic count, 3.4 mitotic figures per 25 wide-field high power fields). Eight tumor had > or =10 mitoses per 25 wide-field high power fields. All patients were initially managed by local excision, and in most of cases, histologic examination showed tumor extending to the tissue edge. Thirty-two of 38 patients (84.2%) with clinical follow-up, ranging from 4 months to 33 years (mean, 14 years 9 months; median, 16 years 1 month), had one (n = 16) or more (n = 16) local recurrence of their fibromatosis.