Spindle cell rhabdomyosarcoma in adults:a clinicopathologic study of nine cases / 临床与实验病理学杂志

ABSTRACT

Purpose To study the clinicopathological features, immunophenotype and differential diagnosis of spindle cell rhabdomyosarcoma in adults (SRMS).Methods The clinical,pathologic and immunohistochemical features were evaluated in 9 cases of SRMS in adults.Results Nine cases of SRMS in adults were retrieved from the pathological archive of this hospital. 7 cases were male and 2 were female. Patients age ranged from 20 to 80 years (median,45 years). The head and neck region,including the right mandible, pharyngeal portion, nasopharynx, and left maxillary,was the most commonly affected area, accounting for 44% of the cases, followed by forearm, waist, thigh, leg and testis(1 case each). Tumor size varied from 2 to 14 cm (median 5.9 cm).Histologically, all the tumors were mainly composed of cellular bands and fascicles of atypical spindlE-shaped tumor cells with a variable number of spindled or polygonal rhabdomyoblasts.In addition, focal areas reminiscent of interstitial sclerosing were presented in 2 cases, and pseudovascular structures were noted in 2 cases, loosely myxoid stroma were detected in 1 case and small solid areas with mild pleomorphic tumor cells were present, but lacking bizarre pleomorphic rhabdomyoblasts. Immunohistochemically, the tumor cells were positive for vimentin, desmin, CD99 and MyoD1; Myogenin and MSA were positive in most of the cases (6/9 and 7/9 each); The remaining antibodies(S-100, CD34,CK and HMB-45) were all negative. Follow-up information was available in all the cases, ranged from 6 months to 4 years, revealed paravenous metastases of the peritoneal cavity in one patient with testis tumor and liver metastases in one patient with leg tumour. 4 patients developed local recurrences and 2 patients died of the disease.Conclusions SRMS is a rare neoplasm in adults,and most commonly occurs in male with preferential involvement in the head and neck region. It appears a more aggressive clinical course in adults. Morphologically, SRMS in adults should be differentiated from other spindle cell tumors.