Thyroid & parathyroid

Other thyroid malignancies


Last author update: 1 June 2015
Last staff update: 12 February 2021

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PubMed Search: sarcoma thyroid

Related Topics: angiosarcoma

Sheren Younes, M.D., Ph.D.
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Cite this page: Younes S. Sarcoma. website. Accessed April 14th, 2024.
Definition / general
  • Primary thyroid sarcomas are rare, usually reported only as case reports
  • Chondrosarcoma: primary thyroid tumors are very rare
  • Kaposi sarcoma: rare site for this tumor, even in HIV patients (0.9%, J Thyroid Res 2014;2014:364146)
  • Leiomyosarcoma: malignant mesenchymal tumor of smooth muscle origin; very rare as primary thyroid tumor; has very aggressive clinical course
  • Synovial sarcoma: distinctive soft tissue neoplasm, 5 - 10% of all soft tissue sarcomas, but very rare in thyroid (Goldblum: Enzinger and Weiss's Soft Tissue Tumors, 6th ed, 2013); presents as rapidly enlarging thyroid mass with normal thyroid function tests
  • Undifferentiated pleomorphic sarcoma (MFH): extremely rare thyroid tumor with median survival of only 9 months (Eur J Surg Oncol 2009;35:649)
Case reports
Clinical images

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Leiomyosarcoma: nodule with heterogeneous uptake

Gross description
  • Chondrosarcoma: well defined, greyish white, with cartilaginous consistency
  • Leiomyosarcoma: solid, unencapsulated tumor with hemorrhage and necrosis
  • Synovial sarcoma: encapsulated mass with lobulated cut surface, grayish tan solid mass with rubbery consistency (J Korean Med Sci 2007;22:S154)
Gross images

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Synovial sarcoma:
well demarcated
lobulated, tan
solid mass

Microscopic (histologic) description
  • Chondrosarcoma: lobular appearance with pleomorphic chondrocytes and infiltration of surrounding thyroid tissue; variable calcification
  • Leiomyosarcoma: spindled cells in fascicular pattern, infiltrating normal thyroid tissue; cells are pleomorphic with abundant eosinophilic fibrillary cytoplasm and irregular intracytoplasmic vacuoles; commonly hemorrhage, necrosis, mitotic figures, atypical mitoses
  • Liposarcoma: invasive tumor composed of spindle to pleomorphic cells, with variable pleomorphism; may have myxoid stroma with arborizing capillaries
  • Osteosarcoma: spindled to epithelioid cells invading and destroying adjacent thyroid; pleomorphic with coarse chromatin and multinucleated cells with foci of lace-like osteoid
  • Synovial sarcoma: biphasic growth pattern with admixture of spindled and epithelial cell components; spindle cell component has fascicles of atypical fibroblast-like cells; epithelial component has solid nests of plump epithelioid cells with well formed glandular structures; cells are pleomorphic and mitotically active
Microscopic (histologic) images

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Compactly cellular

Cigar shaped nuclei

Invades thyroid parenchyma






Chromogranin-, synaptophysin-


Synovial sarcoma: biphasic growth; cytokeratin & vimentin

UPS / MFH: residual thyroid follicles; intersecting bundles of atypical spindle cells

Cytology description
  • Kaposi sarcoma: spindled and plasmacytoid cells
  • Leiomyosarcoma: spindled and plump pleomorphic cells with acidophilic fibrillary cytoplasm in a necrotic / proteinaceous background
  • Osteosarcoma: hypercellular smears of loosely cohesive cells; spindled to epithelioid cells with scant to moderate amphophilic-basophilic cytoplasm, with occasional small cytoplasmic vacuoles; cells may be multinucleated; nuclei are elongated ovals with coarse chromatin and prominent nucleoli; fibrillar, metachromatic extracellular matrix
  • Synovial sarcoma: clusters of pleomorphic spindled and epithelioid cells
Cytology images

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Synovial sarcoma:
spindled and
epithelioid cells

Positive stains
Negative stains
Electron microscopy images

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Synovial sarcoma:
solid nests of
epithelial cells

Molecular / cytogenetics images

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Synovial sarcoma:
SYT-SSX fusion
gene transcript

Differential diagnosis
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