Idiopathic aggressive myositis ossificans of the hand infiltrating the flexor sheath/checkrein ligament, obliterating the common digital artery, and attenuating the digital nerve: A case report

INTRODUCTION: Myositis ossificans of the hand is extremely rare and tumors do not usually infiltrate adjacent structures. We present a very unusual case with a tumor infiltrating adjacent structures. REPORT OF A CASE: A 30-year-old female presented with a 5-week history of a painful rapidly-growing mass over the proximal phalanx of the right ring finger. The mass infiltrated the entire flexor sheath over the proximal phalanx as well as the checkrein ligament of the proximal interphalangeal joint. The common digital artery of the 3rd web space was obliterated by the tumor. The radial digital nerve of the ring finger was stretched and attenuated. Total excision was done and histology confirmed the diagnosis of myositis ossificans. No recurrence was seen at the one-year follow-up. DISCUSSION: Myositis ossificans of the hand is extremely rare. We report our case to document the unique feature of tumor infiltration of adjacent structures. We also document that excision is curative despite the infiltrative nature of the tumor. CONCLUSION: Our case is unique because of the infiltrative nature of tumor. There is no indication for amputation even for infiltrative tumors. We demonstrate that complete excision is curative with good regain of function even in infiltrative lesions.