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Sclerosing Rhabdomyosarcoma
A Clinicopathologic and Immunohistochemical Study of Five Cases

Jian Wang MD, Xiaoyu Tu MD, Weiqi Sheng MD
DOI: http://dx.doi.org/10.1309/EP3FRRY6GMP555QC 410-415 First published online: 1 March 2008


We report 5 cases of sclerosing rhabdomyosarcoma. The patients included 4 adults and 1 adolescent. In the 5 cases, 3 tumors occurred in the head and neck region and 2 in an extremity. Histologically, all 5 tumors were characterized by the presence of abundant extracellular hyaline matrix, mimicking osteoid or chondroid tissue. They were composed mostly of primitive small round cells that displayed diverse growth patterns. In 2 cases, focal areas suggestive of spindle cell rhabdomyosarcoma were present. Typical features of embryonal or alveolar rhabdomyosarcoma were not noted; however, rare strap rhabdomyoblasts were identified in 1 case. Immunohistochemically, all 5 cases showed diffuse immunoreactivity for MyoD1, with varied expression of myogenin, desmin, muscle-specific antigen, and α-smooth muscle actin. All patients underwent surgery, combined with adjuvant radiation therapy or chemotherapy. Of 4 cases with follow-up, recurrence was found in 2. Sclerosing rhabdomyosarcoma represents a special variant of rhabdomyosarcoma and is possibly related to embryonal rhabdomyosarcoma.

Key Words:
  • Rhabdomyosarcoma
  • Sclerosis
  • Soft tissue tumor
  • Immunohistochemistry