Malignant tumors
Myxoid MFH of heart

Topic Completed: 1 November 2013

Minor changes: 27 September 2019

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PubMed Search: Myxoid malignant fibrous histiocytoma heart

Related Topics: Malignant fibrous histiocytoma

Nat Pernick, M.D.
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Cite this page: Pernick N. Myxoid MFH of heart. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/hearttumormfhmyxoid.html. Accessed July 7th, 2020.
Definition / general
  • Bland spindle cell sarcoma with diffuse myxoid background
  • Previously called myxosarcoma or fibromyxosarcoma
  • Benign myxomas do NOT transform to myxoid MFH
  • Usually left atrium
  • Poor prognosis
Case reports
Gross description
  • Gelatinous, multilobated, usually sessile endocardial tumor
  • May be multiple or infiltrate myocardium
Microscopic (histologic) description
  • Loose storiform pattern, aggregates or single cells that are bland, spindled and resemble myxoma cells
  • Diffuse background of amphophilic proteoglycan
  • Prominent arborizing vessels
  • Foci of atypical hyperchromatic cells with mitotic figures
  • May infiltrate myocardium
Microscopic (histologic) images

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Hyperchromatic spindle cells in myxoid background but no ring or cord structures

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Focal infiltration of atrial muscle

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Atypical spindle cells in hyalinized background

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Cellular area

Differential diagnosis
  • Myxoma: cord and ring structures infiltrated by mononuclear inflammatory cells, less cellular and pleomorphic than MFH; no extensive branching vasculature, no myocardial infiltration; must sample extensively to rule out myxoid MFH
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