Granulocytic Sarcoma in a Patient With Myelodysplastic Syndrome

Granulocytic sarcomas (GS) are uncommon extramedullary tumors composed of immature cells of the granulocytic or myeloid series. Treatment for GS should be directed toward the underlying hematologic disorder. There is no standard treatment. Granulocytic sarcoma (GS) is seen in ~5% of myeloid leukemia cases and represents the "tissue phase" of the disease. GS can also be seen in patients with chronic myeloproliferative disorders or myelodysplastic syndromes (MDS).[1,2] It antedates the development of acute myeloid leukemia (AML) by about 1 to 2 years.[2] Common sites of involvement include the skin, gums, lymph nodes, soft tissues, periosteum, and bone. Involvement of the gastrointestinal (GI) tract is very rare and commonly involves the small intestine presenting with intestinal obstruction or perforation.[3-5] Gastric GS may occur as gastric ulcers or polyps, and patients most often present with an acute GI bleed.[4-6] Well-differentiated GS consists of tumor cells of myeloid origin showing various stages of maturation. The specific esterase stain, chloroacetate esterase (also called Leder stain), stains neutrophils, neutrophil precursors, eosinophils, and mast cells and confirms the granulocytic nature of the tumor. Various karyotypic abnormalities are seen in primary GS or AML with GS such as t(8,21), 11q23, and inv(16).[7-9] Molecular analysis such as fluorescence in situ hybridization (FISH) can also help detect specific cytogenetic abnormalities. Treatment for GS should be directed toward the underlying hematologic disorder, but there is no standard treatment. Treatment of symptomatic GI tract GS poses a special challenge. Most physicians treat granulocytic sarcoma as AML using standard chemotherapy regimens.[10] However, care should be taken to avoid premature induction therapy, since treatment of MDS-associated GS does not prolong survival. Patients with MDS, who develop GS as a marker of disease acceleration and transformation to AML, have a poor prognosis and survival despite aggressive chemotherapy.[11,12]