Bizarre parosteal osteochondromatous proliferation of the fifth metatarsal (Nora's lesion)—Case report

• Published in: Foot and ankle surgery 2006, Vol.12 (4), p.211-214
• Main Authors: Walsh, J.C., Murphy, D., Freihaut, R.B., O’Keane, J.C., Stephens, M.M.
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Bizarre parosteal osteochondromatous proliferation of bone; Bone tumour; BPOP; Digestive system; Diseases of the osteoarticular system; Investigative techniques, diagnostic techniques (general aspects); Medical sciences; Nora's Lesion; Orthopedic surgery; Osteochondroma; Radiodiagnosis. Nmr imagery. Nmr spectrometry; Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases; Tumors of striated muscle and skeleton
• ISSN: 1268-7731; 1460-9584
• DOI: 10.1016/j.fas.2006.04.004

We report a case of Nora's lesion (bizarre parosteal osteochondromatous proliferation) of the fifth metatarsal. A 56 year old male, presented with a painless, gradually enlarging swelling over the lateral aspect of his left foot, of 2 years in duration. Plain radiography and MRI showed features consistent with a bizarre parosteal osteochondromatous proliferation of bone (Nora's lesion). The mass was excised and the lesion confirmed histologically. This benign lesion can be confused with malignancy. However, it exhibits a number of key radiographic and histological features, which differentiate it from other benign and malignant processes. It has a strong propensity for recurrence. However this can be decreased by excision of the pseudocapsule, underlying periosteum and removal of any abnormal cortical tissue beneath the lesion.