Cardiac tumors - malignant
Synovial sarcoma

Topic Completed: 1 December 2013

Revised: 27 September 2019

Copyright: 2007-2019, PathologyOutlines.com, Inc.

PubMed Search: Synovial sarcoma [title] heart

Nat Pernick, M.D.
Page views in 2018: 523
Page views in 2019 to date: 405
Cite this page: Pernick N. Synovial sarcoma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/hearttumorsynovialsarcoma.html. Accessed October 22nd, 2019.
Definition / general
Case reports
Gross description
  • Bulky tumor infiltrates myocardium and pericardial surfaces
Gross images

Case of Week #150

Microscopic (histologic) description
  • Biphasic spindle cell and epithelioid tumor or monophasic with spindle cells
  • Spindle cell component resembles fibrosarcoma and has cellular and edematous areas; spindle cells are small, compact, often with lymphocytic infiltration
  • Epithelioid areas may form glands or nests
  • Often has hemangiopericytoma-like vascular pattern
Cytology description
  • High grade tumor with intimate admixture of spindle and epithelial cells
  • Need ancillary studies to confirm (Acta Cytol 2006;50:683)
Microscopic (histologic) images
Missing Image

Spindle cell tumor with cellular and hypocellular foci

Missing Image

Nests of epithelioid cells

Missing Image

Cytokeratin+ epithelioid cells

Case of the Week #150
Missing Image


Missing Image Missing Image


Missing Image Missing Image


Missing Image


Missing Image


Missing Image


Missing Image


Positive stains
Molecular / cytogenetics description
Differential diagnosis
None have t(X;18) or fusion gene:
  • Mesothelioma: larger spindle cells with more pleomorphism, usually no infiltration of myocardium
  • Malignant peripheral nerve sheath tumor: 50% associated with neurofibromatosis, also associated with major nerve or continuous with neurofibroma; often palisading with monomorphic serpentine cells, geographic necrosis with tumor palisading at the edges, frequent mitotic figures, often bizarre tumor cells, usually CD99+, variable S100 (62%), CD57, p53, CD57
  • Fibrosarcoma: often left atrium, herringbone pattern of compact fibroblastic type cells with tapered nuclei in collagenous or myxoid matrix; no intracytoplasmic glycogen, no perinuclear vacuoles, no pleomorphism, no histiocytoid cells
  • Myxoma: tumor is dominated by myxoid matrix; also complex structures resembling cords, nests, rings or poorly formed glands, often surrounding blood vessels; composed of stellate or globular myxoma cells with abundant eosinophilic cytoplasm, indistinct cell borders, oval nucleus with open chromatin and indistinct nuclei
Additional references
Back to top