Granulocytic sarcoma is an uncommon tumor composed of granulocytic precursor cells. Because it occurs in a variety of clinical settings and because the tumor cells are primitive it is frequently unrecognized during life. This presentation details the authors' experience with 61 biopsy-proven granulocytic sarcomas. The patient age range was from 2 to 81 years (mean 48 years). In eight patients the tumors were multiple. Most common sites of involvement were bone, periosteum, soft tissue, lymph node and skin. Twenty-two tumors occurred in 15 patients with no known disease, 26 occurred in 24 patients with a known myeloproliferative disorder, and 13 occurred in 11 patients with proven acute myeloid leukemia. Thirteen of the 15 patients with no known disease developed acute leukemia in from one to 49 months after the biopsy of their tumors (mean 10 months). Most tumors occurring in patients with a known myeloproliferative disorder were associated with blast crisis. The authors' cases displayed a morphologic range from well-differentiated to those tumors that displayed virtually no evidence of differentiation by conventional microscopy. It was therefore not surprising that most tumors were originally diagnosed as lymphoma. Chloro-acetate esterase (CAE) stains were performed on 56 tumors and 47 were studied with antilysozyme immunoperoxidase technique. Fifty-six of the 57 specimens studied by either technique were positive. Antilysozyme immunoperoxidase stains were particularly useful in confirming the diagnosis.

These findings suggest that IVL represents a high-grade non-Hodgkin's lymphoma (NHL) with a propensity for systemic dissemination, and that CR and long-term survival may result in patients treated with aggressive combination chemotherapy.

The classification of natural killer (NK)-cell and NK-like T-cell malignancies has undergone significant evolution in recent years. Although examples of NK-cell tumors resembling acute leukemia have been described anecdotally as blastic, blastoid, or monomorphic NK-cell leukemia/lymphoma (NKL/L), the clinical and pathologic features of these tumors have not been systematically defined. We report four patients with blastic NKL/L and describe the clinical, pathologic, and immunophenotypic findings in these cases. All patients were elderly (58-82 years) and presented with cutaneous plaques. Two patients also had adenopathy, and three patients had marrow involvement at presentation. Biopsy of cutaneous lesions showed atypical superficial and deep dermal lymphoid infiltrates. Involved lymph nodes were architecturally effaced by an interfollicular infiltrate with blastic cytologic features. In Wright-Giemsa-stained blood or marrow smears, tumor cells had finely distributed nuclear chromatin, many with nucleoli, and variable amounts of cytoplasm. In contrast to many NK and NK-like T-cell disorders, azurophilic cytoplasmic granules were absent or inconspicuous. The tumor cells were immunophenotypically distinctive. They expressed intermediate density CD45, as is characteristic of blasts; in addition, the cells were positive for HLA-DR, CD2, CD4, and the NK-associated antigen CD56. Surface CD3, cytoplasmic CD3, and CD5 were negative in all cases tested, whereas CD7 was expressed in two cases. In formalin-fixed tissue, tumor cells marked with antibodies to CD43, but not with other T- or B-lineage-related antibodies. All three cases studied for Epstein-Barr viral RNA by in situ hybridization were negative. Although treatments varied, all three patients with clinical follow-up died within months of the diagnosis. The clinical course in two patients culminated in an overtly leukemic phase. These findings suggest that blastic NKL/L represents a distinct clinicopathologic entity, characterized by cutaneous, nodal, and marrow involvement by blastic cells with immunophenotypic characteristics of true NK cells. The disease afflicts elderly patients, pursues an aggressive course, and may culminate in overt leukemia.