Mesenchymal tumors

Pulmonary myxoid sarcoma

Editor-in-Chief: Debra L. Zynger, M.D.
Paul J.L. Zhang, M.D.

Topic Completed: 6 June 2019

Minor changes: 12 May 2021

Copyright: 2019-2021,, Inc.

PubMed Search: Primary pulmonary myxoid sarcoma full text[sb]

Paul J.L. Zhang, M.D.
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Cite this page: Gui H, Zhang PJL. Pulmonary myxoid sarcoma. website. Accessed September 22nd, 2021.
Definition / general
  • Low grade tumor
  • Typically in or close to large airways
  • Lobulated tumor with spindle and stellate cells arranged in lace-like strands and cords within prominent myxoid stroma
Essential features
  • Endobronchial nodular mass with reticular / lace-like growth pattern and abundant myxoid stroma
  • Expresses EMA and vimentin, negative for most other markers
  • FISH positive for EWSR1 rearrangement (85%)
  • Low grade malignant myxoid endobronchial tumor
ICD coding
  • ICD-O: 8842 / 3 - primary pulmonary myxoid sarcoma
  • ICD-10: C34.9 - malignant primary bronchiogenic / bronchogenic neoplasm
  • Mean age = 46.3 years; F:M = 1.4:1 (24 cases)
  • 40% with cough, hemoptysis, chest pain; 20% present as incidental lung mass (Am J Surg Pathol 2011;35:1722)
  • Relies on histology, immunohistochemistry and FISH in biopsy or surgical resection
Radiology description
  • Mass related to bronchus, predominantly endobronchial
Radiology images

Contributed by Hongxing (Simon) Gui, M.D., Ph.D.

Endobronchial mass

Prognostic factors
  • Patients with EWSR1 rearrangement have favorable prognosis; wild type EWSR1 portends poor clinical outcome (Pol J Pathol 2017;68:261)
Case reports
Gross description
Microscopic (histologic) description
  • Lobulated architecture, reticular or lace-like pattern with anastomosing cords and strands, abundant myxoid stroma, often lightly basophilic (Am J Surg Pathol 2011;35:1722)
  • Oval, spindle to polygonal cells with minimal to moderate atypia, infrequent mitotic figures with the majority < 5/10 high power fields
  • Admixed lymphoplasmacytic infiltrate
Microscopic (histologic) images

Contributed by Hongxing (Simon) Gui, M.D., Ph.D.

Nodular mass

Reticular pattern

Multinodular growth

Spindle cells

Positive stains
Electron microscopy description
  • Focal dense plaques present in the plasma membrane, external lamina and intermediate junctions are rarely observed (Virchows Arch 2014;465:453)
Molecular / cytogenetics description
Sample pathology report
  • Lung, right lower lobe, lobectomy:
    • Primary pulmonary myxoid sarcoma (see comment)
    • Comment: H&E sections demonstrate a well circumscribed endobronchial tumor composed of lobules of spindled and stellate cells arranged in a reticular pattern within a myxoid background. A chronic inflammatory infiltrate is seen throughout the tumor. Immunohistochemically, the tumor cells are positive for EMA and negative for AE1 / AE3, CAM5.2, pancytokeratin, p40, desmin, actin - alpha smooth muscle, CD34, TTF1, c-kit, vimentin, CD1a and S100. A FISH test for EWSR1 was positive for rearrangement in the tumor cells. The morphology in combination with the FISH test result confirm the above diagnosis.
Differential diagnosis
Board review style question #1
Which of the following is a good prognostic factor for this primary pulmonary lung lesion?

Primary pulmonary lung lesion

  1. Brisk lymphoplasmacytic infiltrate
  2. FISH positive for EWSR1 translocation
  3. Lack of tumor necrosis
  4. Middle age onset
  5. Size > 5 cm
Board review style answer #1
B. Primary pulmonary myxoid sarcoma tumors (shown in photo) with EWSR1 rearrangement have a relatively good prognosis

Comment Here

Reference: Primary pulmonary myxoid sarcoma
Board review style question #2
Which of the following entities is the closest mimicker of primary pulmonary myxoid sarcoma?

  1. Epithelioid hemangioendothelioma
  2. Extraskeletal myxoid chondrosarcoma
  3. Inflammatory myofibroblastic tumor
  4. Myoepithelioma
  5. Myxoid angiomatoid fibrous histiocytoma
Board review style answer #2
E. Myxoid angiomatoid fibrous histiocytoma and primary pulmonary myxoid sarcoma have many overlapping features

Comment Here

Reference: Primary pulmonary myxoid sarcoma
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