CYSTIC PULMONARY METASTASES OF ENDOMETRIAL STROMAL SARCOMA OF THE UTERUS, MIMICKING LYMPHANGIOMYOMATOSIS - A CASE-REPORT WITH IMMUNOHISTOCHEMISTRY OF HMB45

A case of endometrial stromal sarcoma (ESS) showed cystic pulmonary me tastases mimicking lymphangiomyomatosis (LAM). A 58-year-old female, w ho had undergone total hysterectomy for low-grade ESS 16 years previou sly, had repeated bouts of pneumothorax. Multiple thin-walled cysts in the peripheral lung were revealed by radiological examinations. In an open-lung biopsy specimen, cystic lesions were surrounded by layers o f spindle-shaped cells of varying thickness that resembled LAM, Howeve r, in addition to subtle histologic differences from LAM, HMB45 (antim elanoma antibody) showed positive in LAM (n=3), but was negative in ES S (n=2) and the cystic lesions of this case, Using myogenic markers (d esmin and alpha-smooth muscle actin), metastatic ESS could be immunohi stochemically differentiated from mesenchymal cystic hamartoma (n=1). HMB45 immunohistochemistry is useful in the differential diagnosis of cystic pulmonary lesions.