Semin Musculoskelet Radiol 2023; 27(S 01): S1-S24
DOI: 10.1055/s-0043-1770033
Educational Poster

Bizarre Parosteal Osteochondromatous Proliferation: An Educational Review

Dr. Salvatore Gitto
Dr. Francesca Serpi
Dr. Domenico Albano
Dr. Carmelo Messina
Dr. Antonina Parafioriti
Prof. Dr. Luca Maria Sconfienza

Purpose or Learning Objective: To familiarize readers with imaging features and the differential diagnosis of bizarre parosteal osteochondromatous proliferation (BPOP) and also address pathologic presentation and treatment options.

Methods or Background: BPOP is a surface-based bone lesion belonging to the group of benign chondrogenic tumors. The peak of incidence is in the third and fourth decades of life, although it can occur at any age. Hands are the most common location of BPOP (55%), followed by feet (15%) and long bones (25%).

Results or Findings: On imaging, BPOP appears as a well-marginated mass of heterotopic mineralization arising from the periosteal aspect of the bone. Typical features of BPOP are contiguity with the underlying bone and lack of corticomedullary continuity; cortical interruption and medullary involvement are rarely reported. Histologically, BPOP is a benign bone surface lesion characterized by osteocartilaginous proliferation with a disorganized admixture of cartilage with bizarre features, bone, and spindle cells. Differential diagnosis includes both benign (e.g., florid reactive periostitis, osteochondroma, subungual exostosis, periosteal chondroma, and myositis ossificans) and malignant lesions (e.g., periosteal chondrosarcoma and surface-based osteosarcoma). Treatment consists of surgical resection. Local recurrences are common and treated with re-excision.

Conclusion: BPOP must be included in the differential diagnosis of mineralized masses arising from the periosteal aspect of bone cortex. If location and imaging features strongly suggest BPOP, such as mineralized lesions arising from the phalanges with no cortical erosion or medullary involvement, a watchful waiting strategy with follow-up imaging examinations can be adopted. If clinical and imaging presentation is unclear, biopsy should be performed as the next step. Familiarity with multimodality imaging characteristics, pathology features, and differential diagnosis is desirable to offer optimal patient care.

Publication History

Article published online:
26 May 2023

© 2023. Thieme. All rights reserved.

Thieme Medical Publishers, Inc.
333 Seventh Avenue, 18th Floor, New York, NY 10001, USA