Soft tissue
Skeletal muscle
Pleomorphic rhabdomyosarcoma

Author: Erdener Özer, M.D., Ph.D. (see Authors page)
Editorial Board Member Review: Michael Clay, M.D.
Deputy Editor Review: Debra Zynger, M.D.

Revised: 29 March 2018, last major update February 2018

Copyright: (c) 2002-2018, PathologyOutlines.com, Inc.

PubMed Search: Pleomorphic rhabdomyosarcoma[TI]

Cite this page: Özer, E. Pleomorphic rhabdomyosarcoma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/softtissuepleomorphicrhabdo.html. Accessed October 15th, 2018.
Definition / general
Essential features
  • High grade sarcoma composed of atypical cells that display skeletal muscle differentiation
  • No embryonal or alveolar component of rhabdomyosarcoma
Epidemiology
  • Usually older than 50
  • 70% male
Clinical features
  • Rapidly growing, painful mass, most commonly of lower extremity
Radiology images

Images contributed by Erdener Özer, M.D., Ph.D.

MRI



Images hosted on other servers:

MRI

Case reports
Treatment
  • Clinical behavior and responsiveness to chemotherapy are similar to adult high grade soft tissue sarcomas
  • Poor prognosis; 70% die of disease after mean follow up of 20 months (Mod Pathol 2001;14:595)
Gross description
  • Mean 7 cm, up to 30 cm
  • White firm cut surface with variable hemorrhage and necrosis
  • May be confined to fascial compartment and assume shape of muscle from which it arises
Gross images

Images contributed by Debra Zynger, M.D.

Thigh mass



Images hosted on other servers:

Paratesticular tumors

Resected tumor

Microscopic (histologic) description
  • Sheets of large, atypical and frequently multinucleated polygonal eosinophilic cells
  • Sometimes undifferentiated round to spindle cells
  • Cross striations are seldom detected
Microscopic (histologic) images

Images contributed by Burcin Tuna, M.D.

H&E, x10

H&E, x20

Desmin, x10

MyoD1, x20



AFIP images:

Fascicular pattern

Storiform pattern

Patternless pattern

Hemangioperi-cytoma-like pattern


Spindle cells

Pleomorphic and polygonal cells

Epithelioid cells with abundant eosinophilic cytoplasm

Clear cytoplasm due to washing out of glycogen

Positive stains
Electron microscopy description
  • Skeletal muscle differentiation with rudimentary sarcomeres containing Z bands or Z band material with thick and thin filaments
Electron microscopy images

Images contributed by Mark R. Wick, M.D.
Molecular / cytogenetics description
Differential diagnosis
Board review question #1
Which of the following is true for pleomorphic rhabdomyosarcoma?

  1. Are usually tumors of children
  2. Composed of an embryonal component
  3. Copy number pattern seen differs from alveolar rhabdomyosarcoma
  4. May express pankeratin
  5. Tumor cells often display cross striations
Board review answer #1
C. Copy number pattern seen differs from alveolar rhabdomyosarcoma