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Myeloid Sarcoma (Leukemia)

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  • Involvement is uncommon, usually as a secondary involvement detected on testicular biopsy.
  • Leukemia – systemic, blood or bone marrow involvement; myeloid sarcoma – tumoral mass consisting of leukemic cells (image A).
  • Frequent findings in autopsy, about half of acute leukemia patients and ~1/5 of chronic leukemia patients have testicular involvement.
  • May occur in adults or children depending on the type of leukemia.

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  • Gross: tumor may have greenish hue because of myeloperoxidase (so called chloroma).
  • Morphologically overlaps with lymphoma, but has more variable cytology, can have more cytoplasm (particularly immature monocytic cells) and distinctive immature eosinophils may be present
    (image B), (image C), & (image D).
  • Immunohistochemistry: myeloperoxidase+ and some CD117+ (beware of this overlap to GCT).
  • Testicular involvement by leukemia predicts systemic relapse.