Achilles tendon nodule: inflammation, rupture, or tumor?

Fibroma of tendon sheath located within Kager's triangle

The formation of a fibroma of the tendon sheath, a rare, slow-growing, benign tumor, usually occurs in the upper extremities of young adult males. We present an extremely rare case of a fibroma of the tendon sheath arising adjacent to the Achilles tendon within Kager's triangle in a 41-year-old female. The patient presented with progressive pain localized to the posterior aspect of the left ankle. Complete excision and histopathologic analysis of the fibroma were performed. The patient experienced an uneventful recovery after the intervention and had no evidence of recurrence after 3 months of follow-up. Fibroma of the tendon sheath should be included in the differential diagnosis when a patient presents with a painful soft tissue mass in Kager's triangle.

A lipoma within the Achilles tendon sheath

We report a case demonstrating a rare finding associated with a relatively common injury. Lipomata are rarely found within tendon sheaths; but in the case of our patient, at the time of operative repair for a ruptured Achilles tendon, we found a fatty growth within the tendon sheath. The diagnosis of a lipoma was confirmed by histology. Although uncommon, it remains important to be aware of the existence of neoplastic growths within tendon sheaths and to establish the exact nature of these growths by histological analysis.