CD5-positive follicular lymphoma: prognostic significance of this aberrant marker?

Follicular lymphomas are the most common of the clinically indolent non-Hodgkin lymphomas. The immunophenotypic pattern of follicular lymphoma classically demonstrates the B-cell markers CD19, CD20, CD22, CD79a, surface immunoglobulin and CD10. The tumour cells are usually negative for CD5. We described two cases of CD5-positive follicular lymphoma. This finding has rarely been described. Our aim was to discuss two cases of CD5-positive follicular lymphoma and review the published literature on the significance of CD5 expression. Bone marrow biopsies showing involvement with follicular lymphoma at our institution over the past 34 months were evaluated for the presence of CD5 positivity by flow cytometry and immunohistochemistry. Two of eight cases (25%) of the follicular lymphomas with marrow involvement at our institution were found to be CD5-positive. Only 36 cases of CD5-positive follicular lymphoma have previously been described in the literature. The clinical and therapeutic significance of this remains uncertain. More research into such cases may establish whether the presence of this aberrant marker bears prognostic significance.

Two-faced haemophagocytic lymphohistiocytosis: comparative review of two cases of adult haemophagocytic lymphohistiocytosis.

Haemophagocytic lymphohistiocytosis (HLH) is a rare but potentially fatal disease of children and adults. Cytokine dysfunction, uncontrolled accumulation of activated T-cells and histiocytes, and the inability to terminate the immune response lead to the clinical manifestations of extreme inflammation and end-organ damage. HLH is notoriously underreported because of its ability to mimic many other common diseases. Here, we outline two cases of HLH, one primary and the other secondary, to highlight some of the differences and to discuss therapeutic principles and emerging concepts.

Excessive EDTA induces morphologic changes in bone marrow smears that mimic specific features of dysplasia.

INTRODUCTION: The WHO 2008 guidelines recommend that bone marrow (BM) slides for the morphological assessment of dysplasia should be made from freshly obtained BM specimens, and that specimens exposed to anticoagulants for more than two hours are unsatisfactory. However, BM aspirates may be exposed to excessive concentrations of anticoagulant, due to underfilling of the tube or inadequate mixing of the specimen. Here, we document the morphologic changes in BM smears resulting from exposure to excessive concentrations of ethylenediaminetetraacetic acid (EDTA). METHODS: Subjects with normal morphology in BM smears without anticoagulant were studied. Smears without anticoagulant and smears made from BM stored in excessive EDTA for 2 h at room temperature were stained with May-Grünwald Giemsa, and cell morphology was evaluated microscopically. Neutrophil and megakaryocyte size were measured using a calibrated microscope eyepiece graticule. RESULTS: Excessive EDTA concentrations induced progressive nuclear and cytoplasmic contraction with respective membrane damage, cell smudging and pyknotic nuclei. In the granulocytic and megakaryocytic series, hypolobated neutrophils, small neutrophils and micromegakaryocytes were increased in number. In erythroblasts, nuclear contour irregularities were induced, but in general, artifactual changes did not mimic dyserythropoiesis. With excessive EDTA concentrations, morphologic features of erythroblasts and megakaryocytes were obscured by nuclear and cytoplasmic contraction. CONCLUSION: Excessive EDTA induces morphologic changes in BM smears that mimic the specific dysplastic features of hypolobated neutrophils, small neutrophils, and micromegakaryocytes. BM aspirates should be collected into an appropriate concentration of EDTA to minimize such artifacts.