22 August 2016 (Monday) - Hairy Cells

An interesting case; A 63-year-old woman being followed for splenomegaly presented with lymphocytosis

·         haemoglobin, 14 g/dL

·         neutrophils, 2.5 × 10^9/L

·         lymphocytes, 8.5 × 10^9/L

·         monocytes, 0.7 × 10^9/L

·         platelets, 200 × 10^9/L.

A blood smear showed 40% medium-sized lymphocytes with abundant cytoplasm with circumferential projections, similar to those of classic hairy cells. The nucleus had condensed chromatin with a conspicuous nucleolus (see the piccie above).

Now here’s the rub - flow cytometry showed 45% clonal B lymphocytes that expressed CD19 / CD20 / CD22 / CD103 / CD11c and a lack of CD5 / CD10 / CD123 / CD25 / CD200. The BRAFV600E mutation was negative, confirming the diagnosis of hairy cell leukemia-variant (HCL-v).

The article actually says “Despite morphologic similarities, HCL-v is not biologically related to classic HCL (cHCL).” How things have changed. Morphology is not the be-all and end-all which once it was. Immunophenotyping is clearly the way forward. How long will it be before this is a technique available in all district general hospitals?