Michael M. Lewis

MRI of malignant fibrous histiocytoma of soft tissue: analysis of 13 cases with pathologic correlation

We reviewed the magnetic resonance (MR) appearances of 13 malignant fibrous histiocytomas (MFH) of soft tissue and correlated each with the respective lesions histopathology. The MR images were evaluated for signal intensity on T1- and T2-weighted spin echo sequences, homogeneity of the lesion, presence of internal low signal septations, and margin definition. Histologic subtypes of MFH included storiform-pleomorphic, giant cell, myxoid, and inflammatory. We could not establish a correlation between MR appearance and histopathology. Instead, our series exhibited general features suggestive of malignant soft tissue neoplasms, namely poor margin definition, internal low signal septation, and heterogeneous high signal intensity on T2-weighted images.

Transarticular invasion of joints by bone tumors: hypothesis.

Eight bone tumors with associated transarticular invasion of the sacroiliac joints are described. All invaded the true synovial joint and spread to the opposing bone. One tumor was benign, and the other seven were malignant. Five of the seven were primary and two were metastatic cancer. One, a myeloma, invaded the disc spaces between the fourth and fifth lumbar vertebrae and the fifth lumbar vertebra and sacrum as well as the sacroiliac joint. The right facet joints of the two vertebrae were also invaded. After a thorough search of the literature, we find that the sacroiliac joint is the most common joint to be invaded by tumors. This is followed by the vertebral disc spaces and, last, the facet joints. Apart from these joints, we were unable to find any radiographic documentation of other joints being transarticularly invaded by tumors. We noted that there is a direct relation between transarticular tumor spread and joints that lack mobility and that certain tumors, benign and malignant, tend to invade these joints.

Case report: Angiosarcoma occurring in a bone infarct

An unusual case of an angiosarcoma that occurred in a bone infarct is presented. A bone infarct may occasionally dedifferentiate to an osteogenic sarcoma or a malignant fibrous histocytoma. However, the association of angiosarcoma with a bone infarct is extremely rare. To the best of our knowledge, there is only one other report of this association in the English literature.

Fibromyxoma of bone

We report two cases of fibromyxoma, one affecting the iliac crest and the second involving the proximal shaft of the tibia. Fibromyxoma is a rare neoplasm related to benign fibrous tumors and is characterized by exuberant, extracellular, ground substance production. Its histologic appearance is benign and distinctive and can be readily distinguished from that of myxoid chondrosarcoma or chondromyxoid fibroma. The radiographic picture is, however, difficult to interpret, and the entity can be easily mistaken for other tumors.

Case report 796

We have presented a young adult with alveolar soft part sarcoma. The lesion occurred in the ankle region and caused extensive bony erosion that mimicked metastasis. At the time of presentation, gingival and subcutaneous metastases were present. Within a short period, however, the patient developed disseminated lung and skeletal metastases as well.

Case report 795

We described a case of high-grade surface sarcoma of the radius in a 14-year-old boy. The lesion appeared radiologically benign and was confined to the surface. The tumor was resected. At the time of biopsy both lungs showed diffuse metastases. Following surgery the patient underwent chemotherapy and the lung metastases improved. The pertinent literature was briefly discussed.

Case report 794

A rare case of primary leiomyosarcoma of the proximal end of the shaft of the right femur in a 52-year-old man has been reported. Proof was obtained by an open biopsy. The origin, pathological features, and clinical presentation have been discussed. The radiographic appearance, the differential diagnosis, and the poor prognosis of this tumor have also been indicated.

Case report 515

Address reprint requests to: I.F. Abdelwahab, M.D., Associate Professor for Radiology, Department of Radiology, The Mount Sinai Hospital and School of Medicine of City University of New York, NY, USA ankles. Motion at these joints was not painful. On palpation, tenderness on the posteromedial aspect of the calcaneus was noted. It was difficult to evaluate the gait because the child was reluctant to walk, but when she did, she walked with some inversion of the left foot and avoided heel-strike on that foot. Plain radiographs and computed tomography of the left foot showed an expanding, cystic lucency of the entire calcaneus with ballooning (Figs. 1 and 2). Laboratory studies were unremarkable. An open biopsy was performed.

Radiation-induced leiomyosarcoma

A 40-year-old white man presented with a 3-month history of progressive pain over the left sacroiliac region. Sixteen years earlier, he had undergone left inguinal orchiectomy for a left testicular seminoma followed by external radiation to the left side of the pelvis and both para-aortic areas to a total dose of 3000 rads. He did well until 1987 when he developed low back pain due to disc herniation of the lower lumbar spine. His symptoms had markedly improved subsequent to l 0 days of traction. He had no further pain until his present complaint. Physical examination revealed an intact neurovascutar bundle and normal deep reflexes and muscle strength. Plain radiography and computed tomography demonstrated a destructive lesion in the left iliac bone that invaded the left sacroiliac joint and involved the left ala of the sacrum (Figs. 1, 2). Bone scan showed increased uptake in the left sacroiliac region (Fig. 3). An open biopsy was then performed.

Case report 696

A case of chondroblastoma involving the right acetabulum and superior pubic ramus in a 60-year-old man has been presented. Tissue was obtained by open biopsy. The clinical and radiographic characteristics of chondroblastoma in general, and this tumor in particular, were discussed. The histopathology and differential diagnosis were also considered. The relatively uncommon site of the tumor and its occurrence in an older patient made the radiographic diagnosis difficult, and other possibilities were discussed.