Osteosarcomas arising in the epiphysis are extremely rare and easily missed in the diagnostic consideration of epiphyseal tumors. It is the purpose of this study to delineate the clinical pathological characteristics of 'epiphyseal osteosarcoma' under the definition of 'a solitary long bone osteosarcoma radiographically considered an epiphyseal tumor for which the main radiologic differential diagnosis would encompass giant cell tumor, chondroblastoma and clear cell chondrosarcoma'. Four such cases with unusual histopathology were retrieved among 110 cases of osteosarcoma. Their clinical, radiological and pathological features, together with all 10 reported cases, were analyzed. The radiographic diagnoses of our four cases include two giant cell tumors, one chondroblastoma and one clear cell chondrosarcoma but turn out to be fibroblastic, giant cell rich, telangiectatic and epithelioid variant of epiphyseal osteosarcoma. Including our patients, the 14 reported epiphyseal osteosarcomas comprise 8 males and 6 females, the age at presentation ranges from 11 to 39 years, two-third in the second decade, 71.4% affect the femur. Due to their epiphyseal locations, many carry benign radiological diagnoses notably giant cell tumor and chondroblastoma. Epiphyseal osteosarcomas may not only masquerade as benign radiological bony lesions but also assume many histological patterns; orthopedic surgeons, radiologists and pathologists should be aware of such possibility. Their behavior and prognosis are dictated by the histologic types, grading and staging rather than location.

Inflammatory malignant fibrous histiocytoma, in addition to a mass lesion, may present with fever and other constitutional symptoms, mimicking an infectious process. This article presents an extremely rare and unique case of primary osseous inflammatory malignant fibrous histiocytoma, highlighting retrospectively the subtle clinical, radiologic, and pathologic features that can suggest this diagnosis. A 63-year-old woman with a history of nephrectomy for right kidney tuberculosis 20 years ago presented with slowly increasing left hip pain for 6 months. The relatively benign-appearing radiograph and biopsy report of chronic inflammation resulted in curettage and nailing of the lesion. The pathologic diagnosis was chronic osteomyelitis, but culture findings for bacteria and tuberculosis were negative. The patient remained well until 4 months later, when left thigh pain returned with fever and leukocytosis (white blood cell count as high as 20.7×10(9)/L, 80% neutrophils). No source of infection was localized. The patient showed no response to broad-spectrum antibiotics and antituberculous drugs. Radiographs showed substantial enlargement of the femoral lesion and extraosseous extension; biopsy results and review of previous histopathologic findings led to a diagnosis of inflammatory malignant fibrous histiocytoma. The fever gradually resolved and the white blood cell count returned to normal within a few days after segmental resection of the proximal femur tumor and its soft tissue extension. However, deep venous thrombosis developed, resulting in left foot ischemia and toe gangrene, necessitating left below-the-knee amputation. Disseminated metastasis occurred 3 months after tumor resection. The patient declined further aggressive treatment and died 13 months after initial presentation.

Extra-adrenal paraganglioma has never been described in the extremities. A 34-year-old woman complained of an enlarging mass in the right forearm for 18 months. Imaging showed a circumscribed vascular tumor attached to the ulnar nerve; biopsy revealed features of paraganglioma. The resected tumor consisted of zellballen pattern of chief cells staining positively for chromogranin with surrounding S100-positive sustentacular cells. The chief cells contained many neurosecretory granules and mitochondria, whereas the sustentacular cells contained a large amount of rough endoplasmic reticulum and some microfilaments. There was adjacent extensive glomus cell hyperplasia and tumorlet formation. The intraoperative blood pressure dropped abruptly on tumor removal. The serum normetanephrine level decreased from a preoperative level of 1987 pg/mL (normal < 149 pg/mL) to normal after operation. The patient admitted on questioning to a history of paroxysmal attacks of transient palpitation, hand tremors, and sweating; imaging showed no evidence of tumor in other parts of the body, and there was no family history of similar tumor; she remained well 33 months after the operation. This occurrence of functional ulnar nerve paraganglioma with the hitherto undescribed associated glomus cell hyperplasia and tumorlet formation attests to the probable existence of normal sympathetic paraganglia in the extremity and their intimate functional relationship with glomus bodies.