Radiological and histological features of tumoral calcinosis of the dorsum of the foot.

Tumoral calcinosis is a rare condition characterized by large calcific masses occurring predominantly in the juxta-articular regions of the extremities. To our knowledge, occurrences in the foot, particularly in association with bone erosion, have been very rare. A 52-year-old Japanese man presented with a mass in the foot, the size of which increased over a period of 27 years. CT scan and MRI demonstrated a 6 cm x 3 cm x 2.5 cm sized mass. There was bone erosion of the dorsal side of the third metatarsal head. Marginal excision was made. Histopathologically, the mass was composed of amorphous calcification with inflammatory cell infiltration. X-ray diffraction method revealed that the pattern of the mass coincided with hydroxyapatite. The patients had no local recurrence at 5 years after operation.