The cutting-edge infrastructure at Shankara Cancer Hospitals, Bangalore, including the flow cytometry, supports our experts in characterising haematological and other malignancies accurately. Flow cytometry is a technology that simultaneously measures and then analyses multiple physical characteristics of single particles, usually cells, as they flow in a fluid stream through a beam of light. Modern flow cytometers, as in our lab, are able to analyse many thousands of particles per second, in "real-time".
It is similar to a microscope except that, instead of producing an image of the cell, flow cytometry offers high-throughput, automated quantification of specified optical parameters on a cell-by-cell basis. The 3 components of flow cytometry i.e., optics, fluidics and electronic system (Figure 2.) aid in the proper segregation of cells and analysis of the sample for definitive diagnosis, follow-up for residual disease and appropriate therapy of the patients.
It has a broad spectrum of applications in several branches of science including molecular biology, pathology, immunology, virology, plant biology and marine biology. In an oncology set-up like ours, we can use it in diagnosing and subtyping of leukaemia and lymphoma, measuring post-treatment residual disease in leukaemia, CD34 stem cell enumeration for bone marrow transplantation, lymphocyte subset analysis, DNA ploidy, paroxysmal nocturnal haemoglobinuria, platelet function tests and so on. The main advantages of flow cytometry are the faster turn-around time, better quantification of cells and precise characterisation of the cells in question by using multiple antibodies-fluorophores combinations.
We present an interesting case of diagnosis of a type of lymphoma with insights from flow cytometry technology. A 74-year-old female came with complaints of generalised weakness, reduced oral intake and weight loss. On examination, there was splenomegaly and leucocytosis (223x109/uL). Peripheral smear (Fig. 1a and 1b) showed 91% atypical, small to medium-sized lymphoid cells having hairy cytoplasmic projections. Flow cytometry (Fig. 1c and 1d) revealed 90% CD5 and CD10 negative B cells (aqua blue) expressing pan-B cell markers (CD19, CD20, FMC7, CD79b). They were positive for 2 of the 4 hairy cell markers i.e. CD103 and CD11c but negative for CD25 and CD123. BRAFp.V600E by mutation by RT-PCR method was not detected.
Based on the above workup, we labelled this case as Hairy cell leukaemia variant / Splenic B cell-lymphoma/leukaemia with prominent nucleoli (HCLv/SBLPN). However, in our case, not many cells had conspicuous nucleolus. Differential diagnoses are classic hairy cell leukaemia, splenic marginal zone lymphoma and splenic diffuse red pulp lymphoma.
HCLv/SBLPN as per the WHO classification of haematolymphoid tumours (5th edition), is morphologically characterised by atypical lymphoid cells having abundant cytoplasm with hairy projections in the peripheral blood, bone marrow and spleen and is clinically associated with splenomegaly that is, enlargement of the spleen. It varies from the classical hairy cell leukaemia by the presence of leucocytosis without monocytopenia, cells having prominent nucleoli, negative hairy cell markers (CD25 and CD123) and lack of BRAFp.V600E mutation. It is important to correctly identify this variant as it has a more aggressive course and is refractory to standard therapy.
As part of the standard line of care, the patient was started on Rituximab. However, as she developed severe infusion reactions on the first dose, she was provided supportive care and started on cyclophosphamide, which she was able to tolerate. Unfortunately, the patient succumbed to sepsis secondary to pneumonia.
While the outcome was not favourable in this instance, the thorough diagnostic work-up enabled a targeted and informed approach to the patient's treatment. Moreover, the case underscores the importance of correctly identifying such variants, as they often present with a more aggressive clinical course and resistance to standard therapies. This emphasises the ongoing need for advancements in both diagnostic technologies and therapeutic strategies. It also reinforces the necessity for medical professionals to be well-informed about these latest developments in cancer classifications, diagnosis methods and treatment strategies. This improves the outcome for patients facing complex and challenging conditions. The cutting-edge infrastructure and expertise of our consultant doctors at Shankara Cancer Hospitals stand as a testament to our commitment to precise and advanced diagnostic capabilities in the field of oncology. We remain steadfast in our commitment to pushing the boundaries of oncological care, striving for breakthroughs that will ultimately contribute to better prognoses and enhanced quality of life for our patients.
