PRIMARY PULMONARY SARCOMAS WITH FEATURES OF MONOPHASIC SYNOVIAL SARCOMA - A CLINICOPATHOLOGICAL, IMMUNOHISTOCHEMICAL, AND ULTRASTRUCTURAL-STUDY OF 25 CASES

We present 25 cases of a primary pulmonary sarcoma bearing histologica l, immunohistochemical, and ultrastructural features indistinguishable from those of monophasic synovial sarcoma of soft tissue. The patient s were 11 men and 14 women between the ages of 16 and 77 years. Clinic ally, the most common symptoms were chest pain, cough, shortness of br eath, and hemoptysis. The lesions involved all lung segments. Grossly, they varied in size from 0.6 to 20 cm and were described as soft to r ubbery tumors with areas of necrosis and hemorrhage, some with cystic changes. Two lesions involved the bronchial wall and in one case the t umor was described as encircling the bronchial tree. Histologically, a ll of the lesions were characterized by an atypical spindle cell proli feration with a solid growth pattern. Areas of myxoid, neural, hemangi opericytic, and epitheliallike growth pattern were observed. Mitoses, necrosis, and hemorrhage were seen in all lesions in varying proportio ns. Immunohistochemical studies for epithelial membrane antigen (EMA) and keratin showed strong focal positivity in 25 of 25 and 23 of 25 le sions, respectively. Immunohistochemical study for vimentin showed dif fuse strong positivity in all lesions. Other immunostains, including d esmin, smooth muscle actin, and S-100 protein, were negative. Electron microscopy in three cases showed spindle cells with elongated nuclei containing abundant cytoplasmic rough endoplasmic reticulum and well d eveloped desmosome type intercellular junctions. Follow-up information ranging from 2 to 20 years was obtained in 18 patients, Six patients died of their tumors, whereas four patients died of unrelated causes w ithout evidence of recurrence or metastases. Eight patients were alive with disease (recurrence and/or metastases) from 1 to 7 years after d iagnosis. Four patients were alive and well without evidence of recurr ence or metastases from 2 to 20 years (mean followup, 12.5 years). The present group of lesions appears to constitute a distinctive and as y et previously undescribed primary sarcoma of the lung, which probably represents the visceral counterpart of monophasic synovial sarcoma of soft tissue in a pulmonary location. Because of their distinctive biol ogy these lesions should be distinguished from a variety of primary an d metastatic malignancies of the lung. Copyright (C) 1995 by W.B. Saun ders Company