Pleura & peritoneum
Pleura mesothelial tumors

Topic Completed: 1 November 2013

Minor changes: 2 September 2020

Copyright: 2003-2020,, Inc.

PubMed Search: Sarcomatoid mesothelioma pleura

See Also: Mesothelioma

Vaidehi Avadhani, M.D.
Page views in 2019: 2,277
Page views in 2020 to date: 2,933
Cite this page: Avadhani V. Mesothelioma-sarcomatoid. website. Accessed October 24th, 2020.
Definition / general
  • Defined as > 90% spindle shaped tumor cells
  • Termed desmoplastic if > 50% of the tumor shows desmoplastic pattern
  • 10 - 20% of all mesotheliomas
Radiology images

Images hosted on other servers:

Small left pleural effusion

Clumped calcification and pleural effusion

Coarse, clumped calcification

Case reports
Microscopic (histologic) description
  • Conventional, spindle cell type: spindle cells arranged in fascicles or having a haphazard distribution
  • Desmoplastic variant
  • Heterologous differentiation: osteosarcoma, chondrosarcoma or other sarcoma-like areas
  • Lymphohistiocytoid: diffuse large histiocyte-like cells with dense infiltrate of lymphocytes and plasma cells; behaves similar to epithelioid type, some prefer classifying as such (Am J Surg Pathol 2007;31:711)
Microscopic (histologic) images

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Infiltrative spindle cells

Various images

AE1 / AE3, CAM 5.2, calretinin

WT1, D2-40

Cytology description
  • Tumor cells not shed in pleural fluid, which typically contains only reactive mesothelial cells
Positive stains
Negative stains
  • CD31 (positive in angiosarcoma), CD34 (solitary fibrous tumor), S100 (neurogenic tumors but mesotheliomas may show focal staining)
  • CD45
  • May have focal positive muscle markers
Electron microscopy description
  • No specific ultrastructural features
Differential diagnosis
Additional references
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