- 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.
- 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.