Pleomorphic Rhabdomyosarcoma
Khin Thway, BSc, MBBS, FRCPath
Key Facts
Terminology
High-grade sarcoma occurring almost exclusively in adults and displaying evidence of skeletal muscle differentiation
Diagnosis requires identification of pleomorphic rhabdomyoblasts and expression of skeletal muscle specific immunohistochemical markers
Clinical Issues
Older adults
Deep soft tissues of lower extremity
Multiple other sites
Microscopic Pathology
Morphology of pleomorphic sarcoma
Markedly atypical spindle to polygonal cells
Pleomorphic polygonal rhabdomyoblasts may be present
Expression of desmin and myogenic markers
 Pleomorphic rhabdomyosarcoma is shown with sheets of markedly anaplastic, frequently bizarre  or multinucleate  polygonal cells. The morphology is indistinguishable from other pleomorphic tumors. |
 In this specimen, the tumor shows a fascicular architecture with bundles of atypical spindle cells with vesicular or hyperchromatic nuclei. |
TERMINOLOGY
Definitions
High-grade sarcoma occurring almost exclusively in adults and displaying evidence of skeletal muscle differentiation
Diagnosis requires identification of pleomorphic rhabdomyoblasts and expression of skeletal muscle specific immunohistochemical markers
CLINICAL ISSUES
Epidemiology
Age
Older adults
Median: 6th decade
Very rare cases reported in children and adolescents
Gender
M>F
Site
Deep soft tissues of lower extremity, particularly thigh
Abdomen/retroperitoneum
Spermatic cord and testes
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
