Soft tissue
Other tumors
Alveolar soft part sarcoma

Author: Vijay Shankar, M.D. (see Authors page)

Revised: 15 September 2016, last major update November 2012

Copyright: (c) 2003-2016, PathologyOutlines.com, Inc.

PubMed Search: Alveolar soft part sarcoma [title]

Definition / General
  • Rare tumor of deep soft tissue characterized by well defined nests of cells separated by fibrous stroma
  • 0.5 - 1.0% of all soft tissue tumors
  • Deep soft tissue of oral cavity, pharynx, mediastinum, thigh / leg
  • Usually young females
  • Highly malignant, although clinical course is slow / indolent
  • Metastases up to 30 years later to veins, lungs, other
  • Lung metastases may be presenting feature
Prognostic Factors
  • Size, presence of 17q25 abnormality, AJCC stage, age
Case Reports
Clinical Images
Images hosted on PathOut server:

Orbital, courtesy of Dr. Mark R. Wick

CT scan, orbital, courtesy of Dr. Mark R. Wick



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Orbital tumor

Tongue

Nose and thigh

Gross Description
  • Well circumscribed, large, gray - yellow, hemorrhage, necrosis
  • Size ranges from 2 - 14 cm
Gross Images
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Courtesy of Dr. Mark R. Wick


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Deep soft tissue

Micro Description
  • Well defined nests of cells separated by fibrous stroma
  • Alveolar pattern if cells discohesive
  • Composed of large polygonal cells with granular eosinophilic cytoplasm, vesicular nuclei, prominent nucleoli
  • Vascular invasion common; also characteristic rod-shaped crystalloids
  • No / rare mitotic figures, minimal pleomorphism
Micro Images
Images hosted on PathOut server:

Courtesy of Dr. Mark R. Wick

PAS, courtesy of Dr. Mark R. Wick

FE3 stain, courtesy of Dr. Mark R. Wick



Case of the Week #222:


MyoD1

PAS-D

TFE3

Vimentin



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Various images

Tongue

Lobular structure

Loss of cohesion in cell lobules


Thigh mass

H&E

S100

PAS+

Cytology Description
  • Strong similarity to renal cell carcinoma, clear cell type
  • Variably cellular smears composed of large cells with an abundant finely granular or vacuolated cytoplasm, markedly enlarged nuclei / nucleoli, and bare nuclei (Cancer 2009;117:500)
Cytology Images
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FNA, courtesy of Dr. Mark R. Wick



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Figures 1 - 6

Metastatic renal cell carcinoma

Positive Stains
  • PAS+ diastase resistant needle-like structures, MyoD1 (cytoplasmic only)
Electron Microscopy Description
  • Membrane bound crystals with periodicity of 58 - 100 nm and cross grid pattern
  • Numerous electron dense vesicles near Golgi
  • Smooth tubular aggregates associated with plasmalemmal invaginations
  • No features of skeletal muscle differentiation
Electron Microscopy Images
Images hosted on PathOut server:

EM, courtesy of Dr. Mark R. Wick

Molecular / Cytogenetics Description
  • Changes in #1, 5, 13, 17