[Tumeral calcinosis: case report of an erosive form affecting the long finger].

Tumoral calcinosis is characterised by deposits of hydroxyapatite in the soft tissues. The authors report an observation of localization at the level the P.I.P. joint of a ring finger. The lesion appeared to be a subcutaneous tumour but had completely eroded the distal epiphysis of the middle phalanx. The diagnosis was made radiographically and was confirmed by histology. Calcinosis presents in two very different forms; either disseminated or localised. The localised form can invade the juxta-articular gliding spaces. It may exhibit one of two clinical courses: one is acute and diffuse. The other is chronic, localised and insidious and gives rise to tumoral masses arising near joints, but without invading them. An erosive tumoral calcinosis is exceptional. It is characterized by bony right up to the articular surfaces. At the level of the wrist and the hand, tumoral forms are rare and we could only find one other case in the literature and it was localized in the middle finger.