Florid reactive periostitis in the fifth phalange of a professional boxer

RATIONALE Florid reactive periostitis is a rare, benign bone and chondrogenic lesion that develops most frequently in the phalanges of the hands. Although the definitive cause of florid reactive periostitis is unknown, the major inciting factor is generally considered to be trauma, including repetitive minor trauma. PATIENT CONCERNS We present a case of florid reactive periostitis affecting two contiguous phalangeal bones of the left fifth phalange of a 23-year-old male professional boxer. The patient had experienced chronic pain around the metacarpophalangeal joint of the left fifth phalange when punching with the left hand; this pain was improved but not resolved after conservative treatment. INTERVENTIONS Plain radiography of the fifth phalange revealed a bulging bone lesion on the volar side of the proximal phalanx and metacarpal of the left fifth phalange. Computed tomography also showed raised bony lesions on the volar side of these bones without bony destruction or intraregional calcification. Surgery was performed and histopathology revealed that the bone specimens comprised a mixture of fibrous connective tissue and relatively immature bone covered by bland osteoblasts. DIAGNOSES These findings were suggestive of a benign bone formation process, and the lesion was diagnosed as florid reactive periostitis. OUTCOMES The pain and tenderness in the left fifth phalange experienced during boxing had completely resolved by 6 months postoperatively, and 12 years postoperatively the patient had full range of motion and no recurrence of pain. LESSONS Traction force, such as those associated with "leading jabs," may induce repetitive minor trauma and subsequent periosteal damage, resulting in the gradual development of bulging bone ridges on the volar surface of the proximal fifth phalange and metacarpus of the hand.