Recurrent amyloidoma of soft tissue with exuberant giant cell reaction.

Amyloidoma (localized tumorlike amyloidosis) in the soft tissues is rare. We present an instructive case of recurrent amyloidoma in the soft tissue of the ankle in a 45-year-old man with multiple surgical procedures and chronic osteomyelitis of the underlying bones. The lesion evaded diagnosis because of a florid giant cell reaction that led to various misdiagnoses, including giant cell tumor of tendon sheath, foreign body reaction secondary to surgery, and pseudogout. This case demonstrates the importance of considering the possibility of amyloidoma when a giant cell-rich lesion is encountered in the soft tissues.