Oral Myeloid Sarcoma as a Marker of Relapse in Acute Myeloid Leukemia

A 20-year-old woman with acute myeloid leukemia (AML) with monocytic differentiation in remission presented with a recent onset painful indurated swelling on the tongue with fever. Although her peripheral blood picture was normal, the bone marrow biopsy was suggestive of a relapse of AML. A biopsy from the tongue lesion showed diffuse infiltration of lamina propria and submucosa by blast cells, positive for myeloperoxidase and CD11c and suggestive of oral myeloid sarcoma (MS). This presents an uncommon site of occurrence of MS and was a marker of relapse of AML. This case highlights the variable presentation of MS. It should prompt investigation for relapse of hematological malignancy in the bone marrow even in the absence of evidence from peripheral blood.