K. Furuse

Ossifying fibromyxoid tumor of soft parts.

A histologically uncommon soft‐tissue tumor of the extremities and neck of a 54‐year old male is reported. The solid, bony‐hard tumors occurred at the inner region of the right thigh at 44 years of age with additional tumor formation at the posterior region of the same thigh, at the inner region of the right upper arm and at the neck during the following 10 years. All tumors were located in the deep muscle layer. The neck tumor directly invaded the fifth cervical vertebra and later the upper mediastinum. Histologically, all three tumors of the extremities contained mixed lobular growths of round to fusiform cells with myxoid matrix and an extensive bone formation. The tumor cells showed a small round nucleus and eosinophilic cytoplasm lacking cytoplasmic glycogen. The myxoid matrix was stained significantly by alcian blue and colloidal iron and was digested completely by pretreatment with hyaluronidase. Another major component was mature bone trabeculae showing a dense meshwork throughout the entire tumor with active bone formation toward the periphery. Positive immunostaining was obtained against anti‐vimentin and S‐100 protein antibodies. We suggest that this uncommon tumor can be tentatively distinguished as an ossifying fibromyxoid tumor of soft parts, (an entity defined by Enzinger et al.), differing from other previously described soft‐tissue tumors. Acta Pathol Jpn 41: 480–486, 1991.

Osteosarcoma with Prominent Epithelioid Features

Osteosarcoma in the metaphysis to epiphysis of the left femur of a 17 year old male is reported. The lesion appeared osteolytic with sclerotic foci on roentgenographs, accompanied by an extensive tumor shadow in the surrounding soft tissue. While 60% of the tumor was necrotic, histological examination of the remaining viable tissue revealed that it consisted almost entirely of a sheet of epithelioid cells, separated by thin, fibrovascular septa with an alveolar‐like pattern, suggestive of metastatic carcinoma. Only a few areas were characterized by malignant osteoid tissue intermingled with the above cells, showing significant positivity for bone‐specific alkaline phosphatase and 5 nucleotidase, thus permitting a diagnosis of osteosarcoma. Autopsy findings revealed that the metastatic foci were histologically similar to those of the primary tumor. Electron microscopy revealed poor development of cytoplasmic organelles, supporting possible derivation from an osteoblastic cell lineage at an early stage. Acta Pathol Jpn 39: 439 445, 1989.

Intraosseous epidermal cyst of the sacrum. A case report.

An unusual case of intraosseous epidermal cyst is reported. The patient, a 45‐year‐old Japanese female, had suffered from lumbago and dysuria for about 15 years. X‐ray examinations and CT scan revealed an expanded osteolytic tumor without marginal sclerotic change within the sacrum, which anteriorly invaded the surrounding soft tissues at the S2/3 level. At this time, chordoma was suspected, but epidermal cyst with foreign body granuloma was finally diagnosed from biopsy and surgical specimens.