A LIGHT AND ELECTRON MICROSCOPIC STUDY OF A CASE OF RADIATION INDUCED MALIGNANT GIANT CELL TUMOR OF THE SOFT TISSUE

Abstract

ABSTRACTA case of malignant giant cell tumor of the soft tissue in a 59‐year‐old female is presented. Total hysterectomy was performed for uterine carcinoma (histologically squamous cell carcinoma) in 1963, followed by radiation treatment for 6 months. Chronic radiodermatitis developed thereafter on the skin of the hip joint region, buttocks and lower abdominal region. A tumor developed in the lesion of chronic radiodermatitis of the left hip joint region in August 1976 and this was excised on February 23, 1977. Two recurrent tumors and a metastatic lesion in the inguinal lymph node developed, which were surgically removed. The main tumor, measuring 7.5 cm in maximum diameter, was found chiefly in the subcutaneous adipose tissue. Histologically, it was composed of a mixture of fibroblastic spindle‐shaped cells, histiocytic mononuclear cells, bizarre giant cells and osteoclast‐like multinucleated giant cells. Occasionally osteoid tissues were seen. Electron microscopically, undifferentiated cells, fibroblastic cells, monohistiocytic cells, osteoclast like multinucleated giant cells and macrophages were observed, and these cells were considered to be divided into three cell lines, that is an undifferentiated cell line, fibroblastic cell line and histiocytic cell line.The histogenesis of malignant giant cell tumor in this case, is considered to have been from undifferentiated cells to both fibroblastic and histiocytic differentiation through the neoplastic stimulus of radiation.