Giant cell tumor of tendon sheath arising in the toe.

Giant cell tumor of the tendon sheath (nodular synovitis) is a benign soft tissue tumor, usually affecting older women, that most often occurs in the interphalangeal joints of the fingers. Occurrence is rare in children. We present a 12-year-old boy and a 6-year-old girl with giant cell tumors of tendon sheaths occurring in the toes. The tumor from the 12-year-old demonstrated the cytogenetic finding of t(1;2)(p13;q37), which previously has been associated with giant cell tumor of tendon sheath in adults. Giant cell tumors of the tendon sheath occurring in children have similar histological and cytogenetic features as adults, however, there may be a predilection for lower extremity involvement.