Fine-needle aspiration cytology of granulocytic sarcoma: A cytomorphologic analysis

Introduction: Granulocytic sarcoma is a rare extramedullary tumor comprising of immature myeloid cells in an extramedullary site which is commonly found with myeloid leukemia (acute or chronic) or occasionally with chronic myeloproliferaive disorders or myelodysplastic syndrome. GS may also be the initial manifestation of leukemia. Because of the diverse clinical presentation, differentiation of Granulocytic sarcoma (GS) from malignant lymphomas (Non Hodgkin's lymphoma or Hodgkin's lymphoma), extramedullary hematopoiesis, poorly differentiated carcinoma and infections is very important for cytopathologist. Materials and Methods: A retrospective study of total 16 cases of GS diagnosed by FNAC (14 FNAs and 2 pleural effusion fluid specimen) was done. Cytology smears were examined for cytomorphology in conjunction with clinical details. Depending upon the population of the cells present on the smears, GS was categorized as blastic, immature or mature GS. Results: The age of patients ranged from 8 years to 50 years with male dominance. (10 males and 6 females).The most commonest site of aspiration was subcutaneous or soft tissue (9 cases) followed by lymphnodes (4 cases) and breast (1 case). 2 cases of GS involving pleural fluid were also included. A detailed history, clinical examination and relevant investigations of patients showed that GS was secondary to acute myeloid leukemia (AML) in 6 patients, was secondary to chronic myeloid leukemia (CML) in 3 patients, and was secondary to juvenile myelomonocytic leukemia (JMNL) in one patients. 6 patients were presented with concurrent myeloproliferative disorder [AML in 4 patients and CML-CP in 2 patients]. Depending upon the population of the cells present on the smears, GS was categorized as blastic GS (7 aspirates), immature GS (3 aspirates) and mature GS (6 aspirates). Conclusion: FNAC plays important role in diagnosis of GS .GS should be included in the diagnosis of undifferentiated neoplasm of the soft tissue or lymph nodes, even in patients with no clinical suspicion of leukemia .Detailed patients clinical history along with careful morphologic evaluation for granulocytic cell identification should helps to reach a definitive diagnosis.