Bizarre parosteal osteochondromatous proliferation: case report and review of the literature.

Bizarre parosteal osteochondromatous proliferation of bone (BPOP) is a benign lesion that is occasionally misinterpreted as a malignant process. The original reports described lesions exclusively in the hands and feet. However, subsequent reports have included additional sites in the long bones, skull, and maxilla. The differential diagnosis of BPOP includes numerous benign and malignant lesions. The benign differential diagnosis includes osteochondroma and reactive processes. The most important malignant differential diagnosis is parosteal osteosarcoma. We present a case of an 11-year-old boy with recurrent BPOP and review the literature. We discuss the differential diagnosis and pathogenesis of the lesion.