The case presented was of a tenosynovial giant cell tumor, diffuse type. The lesion had an apparent communication with the talonavicular joint, as well as a possible communication with the ankle joint. The inevitable morbidity, as well as the lack of an intraoperative definitive diagnosis, prevented a more radical excision of the lesion. The apparent association with a joint will predilect the patient to a higher rate of recurrence but not, however, to a malignant degeneration.