Background: The term “granulocytic sarcoma” implies extramedullary tumours arising from myeloid malignancies. We report the first case of granulocytic sarcoma at rectum after allogeneic peripheral blood stem cell transplantation (PBSCT) for AML.
Case Report: AML was diagnosed at March 2002 and remission induction and 3 courses of consolidation
chemotherapies administered to the patient. Allogeneic PBSCT from her HLA full-matched
brother was performed at September 2002 during first complete remission.She was reevaluated
for complaints of hematochesia developed 20 months after allogeneic PBSCT. The rectosigmoidoscopy
revealed a polypoid bleeding lesion obstructing the lumen. Leukemic infiltration was found in pathological examination. Abdominopelvic computerized tomography showed a mass lesion filling the entire pelvic cavity. In haematological evaluation, she did not have AML. After the diagnosis of granulocytic sarcoma, localized radiotherapy has been initiated. Her initial response to radiotherapy was well but medullary relapse was developed 2 months after radiotherapy and the patient was dead because of infectious complication.
Conclusions: We report an interesting case of a 40-year-old female with a clinical history of acute myelogenous leukemia post allogeneic peripheral blood stem cell transplantation and complete molecular remission, who was found to have granulocytic sarcoma in rectum. Granulocytic sarcoma should be considered in the differential diagnosis of a rectal mass lesion presenting after PBSCT for AML, even if there is no evidence of medullary disease. Every complaint of the patient should carefully be evaluated and the possibility of granulocytic sarcoma must not be overlooked.

Keywords: acute myelogenous leukemia, granulocytic sarcoma, Rectal Mass, Stem Cell Transplantation