Granulocytic sarcoma of the small bowel, greater omentum and peritoneum associated with a CBFβ/MYH11 fusion and inv(16) (p13q22): a case report

INTRODUCTION: Granulocytic sarcoma (GS) is an extramedullary disease which is composed of immature myeloid cells or myeloblasts and usually occurs in association with acute myeloid leukemia (AML), as an initial presentation or a relapse. GS has been associated with various cytogenetic abnormalities, particularly with the t(8;21) translocation and less frequently the inv(16) type. CASE PRESENTATION: We present a rare case of GS of the small bowel, greater omentum and peritoneum, which caused obstruction, in a patient with AML associated with a CBFβ/MYH11 fusion gene and an inv(16) (p13q22). In this patient there was only mild myeloid hyperplasia in bone marrow aspiration but molecular analysis identified a CBFβ-MYH11 fusion and inv(16) (p13;q22). CONCLUSION: Because of its nonspecific clinical and radiologic findings, this entity can be misdiagnosed and can mimic other solid neoplasms, making it a diagnostic challenge. In a GS with no or minimal morphological changes in bone marrow aspiration it is very important to perform a cytogenetic analysis to benefit from the diagnosis and therapeutic strategy.