A 14 year old boy presented with swelling of the middle finger. X-rays showed calcifications of the palmar surface of the head of the third metacarpal and over the first and second phalanges. The natural course was followed over a period of two years with a diagnosis of calcifying peritendonitis. Due to the increased volume of the calcification deforming the proximal phalanx, the masses were resected revealing a diagnosis of chondroma. The discovery of free foreign bodies in the synovial sheath of the flexors and histological examination established the diagnosis of tenosynovial osteochondromatosis, which is rarely located in the hand. No recurrence has been observed after 8 years of follow-up.