Fine-needle aspiration biopsy of granulocytic sarcoma: a clinicopathologic study of 27 cases.

BACKGROUND. Because of morphologic similarities, the differential diagnosis of granulocytic sarcoma (GS) in fine-needle aspiration (FNA) specimens includes non-Hodgkin or Hodgkin lymphoma, extramedullary hematopoiesis, poorly differentiated carcinoma, and infection. METHODS. Twenty-six FNAs and 1 pleural effusion fluid specimen of GS obtained from 23 patients were reviewed for cytomorphologic features and clinical characteristics. The cases were categorized as blastic, immature, or mature GS based on the population of the cells present on the smears. RESULTS. The patients included 18 men and 5 women (mean age, 54 years). Aspiration sites included subcutaneous or soft tissue (15 cases), lymph nodes (5 cases), bones (3 cases), testis (1 case), ileum (1 case), and liver (1 case). One sample of pleural effusion fluid also was included. Review of the patients' clinical history revealed that GS was secondary to chronic myelogenous leukemia (CML) in 17 patients, was secondary to chronic myelomonocytic leukemia (CMML) in 2 patients, and was secondary to acute myelogenous leukemia in 2 patients. GS preceded the manifestation of CML in one patient and of CMML in another patient. Based on the proportions of cells, morphologic classification was attempted and revealed blastic GS in 8 aspirates and 1 pleural effusion fluid specimen, immature GS in 13 aspirates, and mature GS in 5 aspirates. Twelve of 22 specimens from extranodal sites (55%) demonstrated lymphoglandular bodies in the background. Five aspirates showed rare eosinophilic myelocytes. Auer rods were not identified in any of the aspirates. Immunophenotypic and histochemical studies confirmed myeloid and/or myelomonocytic differentiation. CONCLUSIONS. GS especially can be confused with non-Hodgkin lymphoma because of morphologic similarities of the blasts to large cell lymphoma, the presence of lymphoglandular bodies, and the rarity of Auer rods and eosinophilic myelocytes. In conjunction with careful cytomorphologic evaluation, knowledge of the patient's clinical history and use of appropriate immunophenotypic studies should lead to a correct diagnosis. Cancer (Cancer Cytopathol) 2000;90:364-372.