Solitary preleukemic granulocytic sarcoma as a cause of small bowel obstruction.

Granulocytic sarcoma is an extramedullary tumor composed of immature granulocytic cells. These tumors usually occur simultaneously with or follow after the onset of acute myeloid leukemia (AML) or other myeloproliferative disorders. Rarely, it is the first manifestation of AML which appears several months before the onset of leukemia. We report a case of a 48-year-old man presenting with symptoms of small bowel obstruction. Laparotomy and open biopsy were performed. Immunohistochemical studies showed that the neoplastic cells were of myeloid lineage positive for myeloperoxidase and leukocyte common antigen, but negative for CD3, 20, 56, 79a, and cytokeratin. Initially, there was no evidence of blood or bone marrow involvement suggesting acute leukemia or other myeloproliferative disorders. The findings were consistent with the diagnostic findings of solitary granulocytic sarcoma (preleukemic). However, one month later, bone marrow biopsy revealed 57% myeloblasts. Sequentially, the patient developed FAB M2 acute myeloid leukemia. Induction chemotherapy including cytarabine and idarubicine was done which led to complete remission. Allograft bone marrow transplantation was performed later, and there is no evidence of recurrence till present.