Bizarre parosteal osteochondromatous proliferation: 16 Cases with a focus on histologic variability

Area of Science:

• Orthopedic Oncology
• Skeletal Pathology
• Tumor Histology

Background:

• Bizarre parosteal osteochondromatous proliferation (BPOP) is a rare, benign bone and cartilage tumor.
• It typically presents on the surface of bones, particularly in the hands and feet.
• A distinctive feature is the presence of purplish-blue mineralized cartilage, termed 'blue bone.'

Purpose of the Study:

• To characterize the radiographic, histologic, and histomorphometric features of BPOP.
• To confirm the prevalence and diagnostic significance of 'blue bone' in BPOP.
• To provide an institutional series analysis of this rare bone tumor.

Main Methods:

• Retrospective review of 16 institutional cases of BPOP.
• Analysis of radiographic imaging.
• Histologic and histomorphometric examination of tumor tissues.

Main Results:

• All 16 tumors exhibited components of bone, cartilage, fibrous tissue, and 'blue bone.'
• The relative proportions of these tissue types varied significantly among cases.
• 'Blue bone' was identified as a consistent and defining feature in every case, even when focal.

Conclusions:

• BPOP is consistently characterized by the presence of 'blue bone,' regardless of the proportions of other tissue elements.
• Radiographic and histologic analysis confirms 'blue bone' as a key diagnostic marker for BPOP.
• This series reinforces the understanding of BPOP's diverse histological presentation while highlighting a unifying diagnostic feature.