Testis : Leukemia
Leukemia involving a prepubertal testis (higher magnification of the previous image). The pattern of infiltration is interstitial. In adults, the leukemic infiltrates are commonly found on autopsy in patients with acute leukemia (40% to 65% of cases) and chronic leukemia (20% to 35%). Myeloid sarcoma may occur in the testis. Patients usually have known leukemia or subsequently develop leukemia. Paratesticular structures are frequently involved. Myeloid sarcoma is frequently mistaken for lymphoma or plasmacytoma due to morphologic similarities. CD45 may be focally positive. Eosinophilic myelocytes, when present, greatly facilitate the diagnosis along with myeloperoxidase, lysozyme, and chloroacetate esterase stains.