Hiroto Kobayashi

Tumors of peripheral nerves : correlation of symptoms, clinical signs, imaging features, and histologic diagnosis

Abstractu2002Objective. To distinguish between benign and malignant tumors in the peripheral nerves. Design and patients. The clinical, imaging and histologic findings of 99 benign and 16 malignant tumors in the peripheral nerves were reviewed retrospectively. Results. Preoperative motor weakness was observed in only six of 99 benign tumors and was mild, while slight to severe motor weakness was present in 15 of 16 malignant lesions. Pain at rest was present in five of 99 benign tumors and in 15 of 16 malignant tumors. All benign lesions showed a smooth tumoral margin, while half the malignant lesions showed an invasive margin on CT or MRI. Thirteen of 28 benign lesions on CT and nine of 23 on MRI showed round to geographic central enhancement, but this pattern was not seen in malignant lesions. Conclusion. Absence of severe motor weakness and a central enhancement pattern strongly suggest a benign nature, while severe rest pain and invasive tumor margin suggest malignant lesions in peripheral nerve tumors.

Ossifying fibromyxoid tumor resembling parosteal osteosarcoma.

Abstractu2002Ossifying fibromyxoid tumor (OFMT) is a rare soft tissue neoplasm which varies in the amount of bone tissue laid down. We report on a case of OFMT in a 59-year-old male which mimicked a large parosteal osteosarcoma on radiography, MRI, and CT. T1-weighted MR images showed high-intensity areas which reflected fatty marrow. The metaplastic bone was connected to the cortex of the femur, but the tumor did not involve the medullary cavity. The tumor was irradiated and the patient was administered chemotherapy. Wide excision of the tumor and hip rotation plasty was performed. The patient has been disease free for 18 months.

Extraskeletal osteosarcoma of the jaw

Extraskeletal osteosarcoma is a rare malignancy, which accounts for 1–2% of all soft tissue sarcomas; occurrence of these tumors in the head and neck is extremely rare. We present a case of extraskeletal osteosarcoma arising in the subcutaneous tissue of the jaw angle, the central portion of which displayed calcification. Imaging findings were interesting in terms of a high grade malignancy in that the tumor was small and well circumscribed; its appearance mimicked a calcified lymph node. The differential diagnosis of this lesion as well as the imaging and pathological features of extraskeletal osteosarcoma are discussed.

Pathological fracture of the femur ten years after successful radiation therapy for metastatic breast cancer.

We describe a case involving a 75-year-old woman presenting with a femur fracture 10 years after radiation therapy for metastatic breast cancer, which developed in the right femur. The lesion showed complete response with bone healing following radiation therapy; however, the patient sustained a femur fracture ten years later. Histological examination of the specimens obtained from the lesion revealed features of radiation osteonecrosis, but there was no histological evidence of tumor. To our knowledge, there has been no reported case of pathological fracture ten years after radiation therapy from radiation osteonecrosis rather than progression of the metastatic lesion. Late complications of radiation therapy should be considered with care, even when metastatic lesions demonstrate complete response to treatment.

WELL-DIFFERENTIATED LIPOSARCOMA OF THE HAND: Case report

Malignant lipomatous tumours of the hands are extremely rare. A 62-year-old man complained of an enlarging, soft, painless mass in his left hand. Magnetic resonance imaging showed a fatty tumour with irregular septa, and an incisional biopsy showed it to be a well-differentiated liposarcoma. The tumour was resected en bloc and he had a course of external beam radiotherapy. Apart from a slight reduction in grip strength he was well 15 months later with no sign of recurrence.Malignant lipomatous tumours of the hands are extremely rare. A 62-year-old man complained of an enlarging, soft, painless mass in his left hand. Magnetic resonance imaging showed a fatty tumour with irregular septa, and an incisional biopsy showed it to be a well-differentiated liposarcoma. The tumour was resected en bloc and he had a course of external beam radiotherapy. Apart from a slight reduction in grip strength he was well 15 months later with no sign of recurrence.

STABILIZATION EFFECTS OF GRAF LIGAMENTOPLASTY

Graf ligamentoplasty with or without decompression was performed consecutively in 22 patients of lumbar degenerative diseases with segmental instability. The clinical course of the patients was evaluated using the criteria of the Japanese Orthopaedic Association (JOA) for assessing treatment of low back pain (29 points in total), and radiological alteration in angular and translational displacements were measured in flexion, extension, or neutral position. The change of an intervertebral vacuum phenomenon (Knutssons sign), as a sign of segmental instability, was observed before and after the surgery. A preoperative JOA score of 13.7 points was significantly improved to 25.0 points with an improvement rate of 75.7% on average by Graf ligamentoplasty. Radiological measurements revealed that the operation reduced the range of motion of the involved segment in both angular and translational modes with the segment realigned in extension. The short-term results of Graf ligamentoplasty was acceptable for lumbar degenerative diseases. The patients in whom Knutssons sign was reduced or disappeared after Graf ligamentoplasty had a better outcome than those with the sign unchanged or increased in size. This suggests that Knutssons sign can be a predictive indicator of the outcome of the surgery.

Osteosarcoma of the Distal Radius Treated With Segmental Forearm Resection, Hand Replantation, and Subsequent Limb Lengthening: Case Report

A 9-year-old girl with osteosarcoma of the radius was treated with segmental forearm resection and replantation followed by forearm lengthening of 11 cm. At 9-year follow-up, she had recovered sensory function, and her pinch and grasp were sufficient for performing daily activities. Functional outcomes evaluated by the Disabilities of the Arm, Shoulder, and Hand questionnaire and International Society of Limb Salvage functional score system were 4/100 and 23/30, respectively.

Focal lymphoid hyperplasia in a lipoma, mimicking liposarcoma

Lipomas may contain nonadipose tissue, which can confound the correct imaging diagnosis because features of such neoplasms can mimic findings associated with well-differentiated liposarcomas. Intratumoral nonadipose tissue, such as muscle, cartilage, and fibrous tissue, may be present in lipomas; however, lymphoid hyperplasia in a lipoma is extremely rare. This report describes a case involving a heterogeneous lipoma in a 55-year-old woman in whom the heterogeneous portion of the tumor was in fact a reactive lymphoid hyperplasia encased by the lipoma. The imaging features of this lesion as well as pathological findings of this unusual tumor are discussed.