Background Bizarre parosteal osteochondromatous proliferation (BPOP) is a benign lesion of bone, and numerous questions remain unresolved regarding its etiology, diagnosis, and treatment. Questions/purposes We present the Scottish Bone Tumour Registry experience of this rare lesion. Patients and MethodsWe performed a retrospective analysis of the Scottish Bone Tumour Registry records. Histologic specimens were reexamined by a musculoskeletal pathologist. Radiographs were reevaluated by a musculoskeletal radiologist.Results From 1983 to 2009, 13 cases (13 patients; six male, seven female) were identified. Their ages ranged from 13 to 65 years. All patients presented with localized swelling. Pain was present in five. Antecedent trauma was present in two. Nine lesions affected the hand, three the foot, and one the tibial tuberosity. Twelve lesions were excised and one was curetted. There were seven recurrences of which six were excised. One lesion recurred a second time and was excised. There were no metastases. Radiographs showed densely mineralized lesions contiguous with an uninvolved cortex. Cortical breakthrough was present in one case and scalloping in another. Histologic analysis characteristically showed hypercellular cartilage with pleomorphism and calcification/ossification without atypia, bone undergoing maturation, and a spindle cell stroma. Conclusions BPOP is a rare benign lesion that probably is neoplastic, with no gender predilection, and affecting patients over a wide age range. Previously trauma was considered an etiologic factor, but this no longer seems to be the case. The rate of recurrence was 50%, which may indicate a more extensive resection is required for this locally aggressive lesion. No metastases were reported.

SummaryThe case of a rare tumour in a rare location is presented, and important aspects of the management of similar clinical scenarios are highlighted. Tonsillar schwannoma is a slow growing lesion presenting in the third to fifth decade of life. Histological diagnosis is made through the identification of Antoni A (Verocay bodies) and Antoni B cells with S-100 expression. A 24-year-old man presented with a 5 cm right tonsillar tumour causing dysphagia and dysphonia for 6 weeks. Tonsillar schwannoma can be diagnosed in the outpatient clinic. CT imaging and tissue biopsy are the appropriate investigations followed by complete surgical enucleation. Schwannoma has the potential for malignant transformation, with no recorded cases of this occurring in the tonsil. BACKGROUND