Nasal cavity, paranasal sinuses, nasopharynx
Other tumors
Rhabdomyosarcoma

Author: Nat Pernick, M.D. (see Authors page)

Revised: 25 May 2018, last major update November 2004

Copyright: (c) 2004-2018, PathologyOutlines.com, Inc.

PubMed Search: Rhabdomyosarcoma[TI] nasal

Cite this page: Pernick, N. Rhabdomyosarcoma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/nasalRMS.html. Accessed September 21st, 2018.
Definition / general
  • Common nasopharyngeal tumor of children (also lymphoma and nasopharyngeal carcinoma - nonkeratinizing - undifferentiated)
  • Most commonly in orbit, nasopharynx, middle ear / mastoid, nose or paranasal sinuses
  • 75% are age 12 or younger; rarely teenagers, adults or elderly
  • 85% are embryonal subtype, including botyroides variant; remainder are alveolar subtype; spindle cell or pleomorphic subtypes are rare
  • Alveolar have high rates of treatment failure
  • Survival varies by site - orbit: 90%; nose, paranasal sinuses, nasopharynx: 45%, other head and neck: 75%
Gross description
  • Small red mucosal nodule or polypoid mass
Microscopic (histologic) description
  • Highly cellular spindle cell tumor with frequent mitotic activity
  • Embryonal: alternating hypercellular and hypocellular fields with myxoid or sparsely collagenized stroma; tumor cells have scanty cytoplasm, small, round / oval nuclei; may have occasional larger cells with abundant, deeply eosinophilic cytoplasm and cross striations
  • Alveolar: fibrous septa lined by single row of tumor cells with additional tumor cells between the septa; may have multinucleated tumor cells, solid areas at periphery; may have clear cell changes due to glycogen (PAS+)
  • Anaplasia: defined as marked hyperchromatic nuclei at least 3x larger than adjacent cells with clearly abnormal mitotic figures
  • Maturation: after chemotherapy or radiation therapy; cells have large amounts of deeply eosinophilic cytoplasm
Positive stains
  • Desmin, myosin, myoglobin, myogenin, myoD1 (must make sure that tumor cells are actually staining, not adjacent skeletal muscle or histiocytes containing necrotic muscle)
Molecular / cytogenetics description
  • t(2;13), t(1;13) in alveolar subtype
Differential diagnosis
Additional references