Granulocytic sarcoma of the breast in a patient with acute myeloblastic leukemia in remission

Abstract A case of granulocytic sarcoma (GS) of the breast in a patient with acute myeloblastic leukemia whose disease was in remission is reported. Rarely hematological tumors such as lymphoma or leukemia affect the breast as primary malignancies, and more frequently involve the breast as part of a widespread multicentric process. GS also called chloroma is a rare manifestation of acute myeloblastic leukemia, mainly composed of premature precursors of the granulocytic series. Our patient presented with swelling in both breasts and with a previous history of acute myeloblastic leukemia diagnosed 6 months before on the basis of a bone marrow biopsy that revealed 85% immature myeloblasts. After induction chemotherapy, a second bone marrow biopsy showed evidence of disease remission with less than 5% blast cells. On ultrasound two inhomogeneous hypoechoic nodules, with irregular margins and without posterior acoustic shadowing, located, respectively, in the inferior inner quadrant of the right breast and in the upper outer quadrant of the left breast were observed. A subsequent mammogram showed heterogeneously dense breasts without evidence of microcalcifications. A fine needle aspiration biopsy was performed and the cytologic results highlighted the presence of immature myeloid cells, mingled with groups of benign ductal cells. On the basis of the negativity of a subsequent bone marrow biopsy, a final diagnosis of mammary infiltration from acute myeloblastic leukemia was formulated. Due to the lack of specificity of mammographic and sonographic features of breast chloroma definite diagnosis of this rare entity must be accomplished by fine-needle aspiration and cytologic markers, especially for accurate differential diagnosis from other breast malignancies, such as lymphoma or carcinoma. The case presented is unusual because of the multicentric location of the GS and because of the onset in a patient considered to be in remission by bone marrow biopsy.