Nineteen patients whose bone marrow smears showed histiocytic hyperplasia with prominent hemophagocytosis were found to have a clinicopathologic syndrome associated with active viral infection. High fever, constitutional symptoms, liver function, and coagulation abnormalities and peripheral blood cytopenias were characteristic findings. Hepatosplenomegaly, lymphadenopathy, bilateral pulmonary infiltrates, and skin rash were often present. Fourteen of the patients were immunosuppressed. Active infection by herpes group viruses was documented in 14 patients and by adenovirus in 1. The bone marrow of most patients also showed decreased granulopoiesis and erythropoiesis with normal to increased numbers of megakaryocytes. Treatment generally consisted of supportive therapy and withdrawal of immunosuppressive drugs. Thirteen patients recovered. Lymph node biopsy and autopsy material showed generalized histiocytic hyperplasia with hemophagocytosis. The relationship of this disorder to familial hemophagocytic reticulosis, familial erythrophagocytic lymphohistiocytosis, histiocytic medullary reticulosis, and malignant histiocytosis is discussed. Immunosuppressive and cytotoxic therapy may be contraindicated in the treatment of this virus‐associated syndrome.

Bone marrow hematogones (B-lymphocyte precursors) may cause problems in diagnosis because of their morphologic and immunophenotypic similarities to neoplastic lymphoblasts. The purposes of this prospective, multiparametric flow cytometry study were to quantify hematogones across age groups and a spectrum of clinical conditions, to identify factors that affect the relative quantity of hematogones, and to compare their immunophenotype with that of neoplastic lymphoblasts. A total of 662 consecutive marrow specimens were analyzed for hematogones using one of two 4-color antibody combinations; hematogones were identified in 528 (79.8%). There was a significant decline in hematogones with increasing age (P < .001), but a broad range was found at all ages and many adults had a relatively high number. Specimens processed by density gradient had a higher mean percent hematogones than those processed by erythrocyte lysis (P < .001). There was a direct decline in hematogones with increasing marrow involvement with neoplastic cells. A total of 8% of the 662 specimens contained 5% or more hematogones: 24.6% of specimens from patients aged less than 16 years and 6.3% from those 16 and older (P < .000 01).

Patients undergoing video-assisted lobectomy had fewer respiratory complications and shorter length of stay. These data suggest video-assisted thoracoscopic lobectomy is safe in patients with resectable lung cancer. Longer follow-up is needed to determine the oncologic equivalency of video-assisted versus open lobectomy.

Five patients with advanced AIDS developed a unique type of high grade primary body cavity-based non-Hodgkin's lymphoma (NHL). The lymphomas were exclusively in serous effusions with no detectable mass disease in the body cavities and no lymphadenopathy or organomegaly. All of the lymphomas exhibited virtually identical morphology, which could not be precisely classified, but appeared to bridge features of large cell immunoblastic and anaplastic large cell lymphomas. Immunophenotypically the lymphoma cells lacked expression of any B- or T-lymphocyte antigens, but expressed CD45 and the activation antigens CD30, CD38, CD71, and HLA-DR. Clonally rearranged immunoglobulin heavy chain and kappa light chain genes were identified by Southern blot analysis. Molecular studies also revealed Epstein-Barr virus (EBV) and Kaposi's sarcoma-associated herpesvirus (KSHV) genomes and germline configuration of the c-myc protooncogene. In two cases studied cytogenetically, the lymphoma cells manifested complex chromosome abnormalities. These lymphomas are clinically and biologically unique and found predominantly in patients with advanced AIDS, in many cases with pre-existing Kaposi's sarcoma.

Morphologic distinction of leukemic lymphoblasts in B acute lymphoblastic leukemia (B-ALL) from their nonneoplastic counterparts in bone marrow (hematogones) can be difficult. Thus, the presence of aberrant antigen expression detectable by flow cytometry may be critical for diagnosis of B-ALL and detection of minimal residual disease. The current study examined the immunophenotype of B-lineage leukemic lymphoblasts in 200 consecutive, unique, pretreatment patient specimens. We found that all cases of B-ALL exhibited multiple immunophenotypic aberrancies by which they can be distinguished from hematogones. The most frequent aberrancies were uniform or a spectrum of expression of terminal deoxynucleotidyl transferase and CD34, underexpression of CD45, overexpression of CD10, underexpression of CD38, and underexpression of CD20. Asynchronous coexpression of CD34 and CD20 was also frequently observed. Of the 200 cases, 86.5% expressed myeloid-associated antigens, and 19.0% expressed 3 or more. Of 200 cases, 9.0% aberrantly expressed T cell-associated antigens. There were significant differences in antigen-expression patterns between adult and pediatric B-ALL. Specific aberrancies correlate with recurrent cytogenetic abnormalities in B-ALL.