Tenosynovial osteochondromatosis of the flexor hallucis longus tendon

We present a case of tenosynovial osteochondromatosis affecting the flexor hallucis longus tendon in a 29-year-old male with chronic ankle pain. Clinical examination was normal. Plain radiographs and MRI revealed multiple calcified lesions. These were removed surgically and histological analysis confirmed the diagnosis.

This condition is rare, particularly in the foot and ankle. This is the first reported case of such a lesion with an absence of any clinically palpable nodules and highlights the need for a high index of suspicion and the need for imaging.