Testis & paratestis

Other tumors

Myeloid sarcoma

Last author update: 1 August 2013
Last staff update: 6 January 2021

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PubMed Search: Granulocytic sarcoma[title] or myeloid sarcoma[title] testis

Jennifer Gordetsky, M.D.
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Cite this page: Gordetsky J. Myeloid sarcoma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/testisgranulocyticsarcoma.html. Accessed May 30th, 2023.
Definition / general
  • Neoplasm composed of immature and mature granulocytes or monocytes that involves an extramedullary anatomic site
  • Includes leukemic involvement of testis
    • Common with ALL: 8% clinically, 20% microscopically; also AML
    • Bilateral involvement common
    • Testis may be first site of relapse
  • Also called chloroma, myeloid sarcoma, monocytic sarcoma, extramedullary myeloid cell tumor, myelosarcoma, myeloblastoma
  • Rare; case reports of ages 24 - 68 years
  • Usually history of myeloid neoplasm, most often acute myeloid leukemia, less often a myelodysplastic or myeloproliferative disease
  • Testicular involvement can be initial manifestation of AML that subsequently involves blood and bone marrow
  • Very rarely, testis is only site
  • Relatively more common with leukemias with prominent monocytic differentiation (acute myelomonocytic or acute monocytic leukemia, chronic myelomonocytic leukemia, Am J Clin Pathol 2005;124:445)
Clinical features
  • Testicular mass, testicular pain, constitutional symptoms (fever, general weakness, night sweats, weight loss)
  • Based on histology and confirmed by immunohistochemical stains or flow cytometry
  • Clinical history can be very helpful
  • AFP and beta HCG within normal limits
Radiology description
Case reports
  • Chemotherapy or radiation therapy, although bone marrow relapse is common
Gross description
  • Cream colored to yellowish tan, rubbery / firm testicular tumor with extensive paratesticular spread
Gross images

Images hosted on other servers:

Cream colored tumor

Microscopic (histologic) description
  • Normal testis architecture is effaced by primitive cells with scant cytoplasm; or cells with eosinophilic, occasionally granular cytoplasm
  • Prominent myelocytes with moderately abundant cytoplasm and round eccentric nuclei, resembling plasma cells
Microscopic (histologic) images

Images hosted on other servers:


Cytology description
  • Cellular, discohesive cells with moderate cytoplasm, large oval to indented nuclei, distinct nuclear membranes
  • Also cells with scant cytoplasm, no eosinophilic granules, round / oval nuclei with prominent nucleoli (Ann Diagn Pathol 2000;4:17, Cancer 2000;90:364)
  • Variable numbers of eosinophilic myeloblasts, myelocytes and other maturing cells with eosinophilic granules - in some cases, myeloid differentiation is absent
  • Lymphoglandular bodies may be present in background
Negative stains
Differential diagnosis
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