Clinicopathologic study of spindle cell/sclerosing rhabdomyosarcoma in nine cases

Abstract:

Objective：To study the clinicopathologic characteristics of a new WHO subtype spindle cell/sclerosing type rhab－domyosarcoma. Methods：The clinicohistological and immunohistochemical features of 9 cases of spindle cell/sclerosing type rhab－domyosarcoma were studied and the literature was reviewed. Results：Spindle cell and sclerosing type rhabdomyosarcoma may exist independently or mix together. Spindle cell areas arranged in swirled pattern with strong expression of Desmin，MyoD1，Myogenin and CD56 and sometimes weak expression of CD34，S-100，SMA. Sclerosing type areas showed small round or spindle cells arranging in different patterns with prominent sclerosing matrix；nuclear fission count and KI-67 positive indexes of sclerosing type areas were higher than those of spindle cell areas. Superficial spindle cell rhabdomyosarcoma had favoured prognosis，while sclerosing type tended to relapse or metastasis；nuclear fission count and KI-67 indexes were helpful for prognosis. Conclusion：Spindle cell and sclerosing type rhabdomyosarcoma may exist together and express specific rhabdomyosarcoma markers；sclerosis may indicate aggressive behav－ior and worse prognosis.