[Sclerosing rhabdomyosarcoma: a clinicopathologic study of four cases with review of literature].
OBJECTIVE
To study the clinicopathologic characteristics of sclerosing rhabdomyosarcoma (SRMS) and its distinction from embryonal rhabdomyosarcoma (ERMS) and alveolar rhabdomyosarcoma (ARMS).


METHODS
The clinical, histologic and immunohistochemical features of 4 cases of SRMS were studied. The literature was reviewed.


RESULTS
All the 4 cases occurred in adults. The age of patients ranged from 20 to 54 years (mean = 41.5 years). The male-to-female ratio was 1:1. The tumor was located in the left wrist, right thigh, right face and right cheek respectively and the tumor size varied from 2.5 cm to 10 cm in dimension (mean = 5.7 cm). Histologically, SRMS was characterized by the presence of large amounts of heavily hyalinized matrix, mimicking osteoid or chondroid tissue. The tumor cells were composed predominantly of primitive small round cells which were arranged in diverse growth patterns, including fascicular, cord-like, single-file, trabecular, microalveolar and pseudovascular structures. A few rhabdomyoblasts were identified in 1 case. A second spindle cell component was focally found in 2 cases, resembling spindle cell rhabdomyosarcoma or peripheral nerve sheath tumor. Immunohistochemically, all cases showed diffuse staining for Myo D1 and focal staining for desmin. The staining for myogenin was often negative. Three of the cases also expressed muscle-specific actin and 2 cases were positive for alpha-smooth muscle actin. They were all negative for h-caldesmon, S-100 protein, CD31, CD34, AE1/AE3 and anaplastic lymphoma kinase protein.


CONCLUSIONS
SRMS differs from ERMS and ARMS morphologically. Recent cytogenetic studies however suggest a histogenetic relationship with ERMS. Familiarity with its morphologic features and immunophenotype may help to distinguish this peculiar variant of rhabdomyosarcoma from a variety of lesions with abundant sclerosing matrix.
Zhu
Lei
L
Department of Pathology, Cancer Hospital, Fudan University, Shanghai 200032, China.
Wang
Jian
J
D000199:Actins / Q000378:metabolism; D000328:Adult; D002813:Chondrosarcoma / Q000473:pathology; D003131:Combined Modality Therapy; D003893:Desmin / Q000378:metabolism; D003937:Diagnosis, Differential; D005153:Facial Neoplasms / Q000378:metabolism / Q000473:pathology* / Q000628:therapy; D005260:Female; D005500:Follow-Up Studies; D006394:Hemangiosarcoma / Q000473:pathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D017570:MyoD Protein / Q000378:metabolism; D012516:Osteosarcoma / Q000473:pathology; D012208:Rhabdomyosarcoma / Q000145:classification / Q000378:metabolism / Q000473:pathology* / Q000628:therapy; D018232:Rhabdomyosarcoma, Alveolar / Q000145:classification / Q000473:pathology; D018233:Rhabdomyosarcoma, Embryonal / Q000145:classification / Q000473:pathology; D012598:Sclerosis / Q000473:pathology; D012983:Soft Tissue Neoplasms / Q000378:metabolism / Q000473:pathology* / Q000628:therapy; D014746:Vimentin / Q000378:metabolism; D055815:Young Adult
D000199:Actins; D003893:Desmin; D017570:MyoD Protein; C057363:MyoD1 myogenic differentiation protein; D014746:Vimentin