ABSTRACT
BACKGROUND Systemic mastocytosis with an associated hematologic non-mast cell lineage disease is a rare entity, and the majority of systemic mastocytosis cases are associated with myeloid neoplasm. Lymphoproliferative disorders are less commonly associated with systemic mastocytosis and a few cases of systemic mastocytosis associated with chronic lymphocytic leukemia have been described in the literature. CASE REPORT We present a case of indolent systemic mastocytosis associated with small lymphocytic lymphoma. The bone marrow biopsy demonstrated mast cells in the form of clusters and perivascular distribution on immunohistochemistry for tryptase, CD2, and CD25 markers. In addition, 30% involvement by small lymphocytic lymphoma was discovered in the form of interstitial lymphoid aggregates composed of small lymphocytes. Flow cytometry showed B-cells positively stained for CD19, CD20, CD5, CD23, and kappa light chains, and the CD38 expression was <5%. CONCLUSIONS In systemic mastocytosis with an associated hematologic non-mast cell lineage disease, the combination of systemic mastocytosis associated with small lymphocytic lymphoma is rare and the management strategy follows the principle of treating the two entities individually as if they are not related. Clinical surveillance is indicated for indolent systemic mastocytosis and low-risk small lymphocytic lymphoma to monitor for disease progression.
Subject(s)
Leukemia, Lymphocytic, Chronic, B-Cell/pathology , Mastocytosis, Systemic/pathology , Female , Humans , Middle AgedABSTRACT
BACKGROUND: The Ly-6 family has many members, including Ly-6C and Ly-6G. A previous study suggested that the anti-Ly-6G antibody, RB6-8C5, may react with Ly-6Chi murine bone marrow (BM) cells. This finding has been interpreted as cross-reactivity of RB6-8C5 with the Ly-6C antigen, and has been generalized to many hematopoietic cell types, using the terminology Ly-6G/C. The present study was undertaken to determine whether anti-Ly-6G antibodies truly cross-react with the Ly-6C antigen on multiple hematopoietic cell types. METHODS: Splenocytes, thymocytes, and BM cells obtained from Ly-6.1 and Ly-6.2 strains of mice were stained with a variety of antibodies to Ly-6C and Ly-6G. Flow cytometric analysis was performed on these populations. RESULTS: Evaluation of anti-Ly-6C and anti-Ly-6G staining showed only Ly-6C expression and no Ly-6G expression on subsets of splenic T and B cells and thymocytes from Ly-6.1 and Ly-6.2 mice. Bone marrow cells were identified that express both Ly-6G and Ly-6C; no Ly-6G+Ly-6C- populations were seen. CONCLUSIONS: Multiple Ly-6C+ hematopoietic cell populations were identified that do not stain with anti-Ly-6G antibodies. This calls into question the use of the Ly-6G/C nomenclature and suggests that epitopes recognized by anti-Ly-6G antibodies should simply be designated Ly-6G.
Subject(s)
Antigens, Ly/immunology , Cross Reactions/immunology , Animals , Antigens, Ly/metabolism , B-Lymphocytes/drug effects , B-Lymphocytes/metabolism , Bone Marrow Cells/cytology , Bone Marrow Cells/metabolism , CD4 Antigens/analysis , CD8 Antigens/analysis , DNA/pharmacology , Mice , Mice, Inbred Strains , Oligodeoxyribonucleotides , Spleen/cytology , Spleen/immunology , Spleen/metabolism , Thymus Gland/cytology , Thymus Gland/metabolismABSTRACT
Acute promyelocytic leukemia (APL) should be distinguished from other subtypes of acute myeloid leukemia (AML) because of the increased risk of disseminated intravascular coagulation (DIC) and its response to arsenic compounds and retinoids. Some cases of AML seem morphologically similar to the microgranular variant of APL (French-American-British [FAB] AML-M3v) but lack the t(15;17). We evaluated 8 cases of APL-like leukemias for subtle morphologic, cytochemical, immunophenotypic, and cytogenetic differences compared with 5 cases of promyelocytic leukemia/retinoic receptor alpha (PML/RARalpha)-positive APL (FAB AML-M3v). We also evaluated both groups for the presence of DIC. No differences among the groups were noted in blast size, chromatin pattern, nuclear morphologic features, intensity of myeloperoxidase staining, or presence of Auer rods. Immunophenotypes were similar; both types of cases lacked CD34 and HLA-DR and were CD13+ and CD33+. Two cases of APL-like leukemias also were CD56+. DIC was present in 2 patients with M3v. Our study shows that there are no definitive morphologic, cytochemical, or immunophenotypic findings that can distinguish these cases from PML/RARalpha-positive APL.
