Bizarre Parosteal Osteochondromatous Proliferation Arising From the Second Rib: A Case Report

Bizarre parosteal osteochondromatous proliferation (BPOP) is a rare benign lesion, first described by Nora et al. in 1983, that typically affects the small bones of the hands and feet. We report a rare case of BPOP arising from the left second rib in a 41-year-old man, which was incidentally detected as a "pulmonary mass" on the chest X-ray during a routine health checkup. CT imaging revealed a lesion measuring 4.1 × 2.2 cm in size in the second left rib, and we performed surgical resection for both diagnosis and treatment. Postoperative histopathological examination revealed the diagnosis of BPOP. This case underscores the importance of including BPOP in the differential diagnosis of rib lesions, especially when the imaging findings suggest a benign osteocartilaginous lesion. Given the potential of the lesion for recurrence, long-term follow-up of persons with BPOP is recommended.