Cytodiagnosis of granulocytic sarcoma of liver arising in a milieu of myeloid metaplasia: a case report

BACKGROUND: Granulocytic sarcoma is an extramedullary tumor that is composed of granulocytic precursor cells. We report an unusual case of granulocytic sarcoma of the liver that arose in the background of myeloid metaplasia. Fine needle aspiration cytology (FNAC) was instrumental in making the diagnosis in absence of previously known Hematlogic abnormality. CASE: A 65-year-old woman presented with multiple nodules in the liver. USG-guided FNAC was performed on them. The aspirates showed many myeloid blasts, myelocytes, metamyelocytes, erytbroid precursors and lympboglandular bodies. We considered a differential diagnosis of granulocytic sarcoma and myeloid metaplasia. The presence of erytbroid precursors prompted us to consider myeloid metaplasia as a differential diagnorsis of granulocytic sarcoma. Peripberal smear showed a leukoerytbroblastic reaction. The patient died, and necropsy from the liver revealed extensive infiltration by undfferentiated blast cells with areas of myeloid metaplasia showing maturing erytbroid, myeloid and megakaryocytic elements. CONCLUSION: When a dual population of predominant myeloid blasts and normoblarts is encountered, a suspicion of granulocytic sarcoma arising in a background of myeloid metaplasia must be kept. Cells of all 3 lineages may not be always seen in myeloid metaplasia, and 1 cell line may predominate, causing a diagnostic dilemma.