Nora's Lesion: Bizarre Parosteal Osteochondromatous Proliferation Causing Splay Foot Deformity: A Case Report.

Nora's lesion, or bizarre parosteal osteochondromatous proliferation (BPOP), is a rare benign lesion that is made up of varying degrees of cartilage, bone, and spindle cells. Most notably, calcification of the cartilage or "blue bone," is a feature of the disorder. The condition principally affects long tubular bones of the hands and feet, and is generally seen in patients in their second and third decades of life. We present a case of BPOP occurring in the second interspace with symptoms that would be consistent with a more common diagnosis of predislocation syndrome, or a second interspace neuroma. This case study may help the clinician in considering a more subtle cause of a splay deformity in the second interspace, and walk through the diagnostic and treatment course for BPOP.

Dedifferentiated chondrosarcoma in patients with multiple osteochondromatosis: report of a case and review of the literature.

Multiple osteochondromatosis (MOS) is a familial disorder of autosomal dominant transmission characterized by the development of multiple exostoses and often derangements of epiphyseal cartilage, sometimes resulting in long bone growth retardation. Patients with the disorder appear to be at increased risk for developing secondary chondrosarcomas. Rarely, dedifferentiated chondrosarcomas may also occur. We report a single case of a 27-year-old man with multiple osteochondromatosis who developed a fatal dedifferentiated chondrosarcoma. Radiographically, the neoplasm arose from the pelvis completely destroying the left pubic ramus. Subsequently, the patient underwent preoperative chemotherapy followed by a left external hemipelvectomy. On pathologic examination, the tumor was characterized by high-grade pleomorphic sarcoma sharply juxtaposed to a low-grade chondrosarcoma. The patient ultimately died of widespread metastatic sarcoma.