Colonic adenomas with extramedullary myeloid tumor (granulocytic sarcoma)

Extramedullary myeloid tumor (EMT) is an accumulation of malignant immature cells of the granulocytic series that is usually green in appearance due to the presence of myeloperoxidase. These invasive and destructive tumors occur most commonly in the skull and surrounding tissues, lymph nodes, skin and soft tissues. Regardless of the site, EMTs are difficult to recognize and may be easily overlooked or diagnosed as malignant lymphoma. EMTs may precede the diagnosis of a chronic myeloproliferative disorder or acute myeloid leukemia, may present coincident with the hematologic diagnosis, or may herald a relapse after therapy. An accurate diagnosis of EMT is of great clinical importance in the ongoing management of hematologic malignancies. We report here two unusual cases of EMT of the colon, which infiltrated adenomatous polyps. We conclude that increased cellularity within the lamina propria of polyps and mucosal surfaces in general should be carefully examined.