Clinicopathological spectrum of hairy-cell leukemia: A single-center study with brief review of Indian literature

ABSTRACT

Objective: The presence of specific chemotherapeutic protocols for hairy cell leukemia (HCL) makes it essential to discriminate this entity from other lymphoproliferative disorders. Hence, awareness of the variations in clinical presentations and immunophenotypic aberrancies is requisite to ensure diagnostic accuracy. Materials and Methods: A retrospective study was carried out to analyze the clinical-pathological profile of patients with HCL diagnosed over a period of 81 months (2010–September 2017) in our institute. Flow cytometry was performed in all the patients, and further, BRAFV600E mutation analysis was performed by real-time polymerase chain reaction in a limited number of samples. Result: A total of 353 lymphoproliferative disorders were assessed during the period, of which 16 (4.5%) were diagnosed as HCL, which included 15 cases of classical HCL and single case of HCL-v. Striking male predominance was noted with a median age of 52 (range 22–90 years). 47% patients presented with pancytopenia, while 20% cases had leukocytosis. Three patients presented with bleeding diathesis in the form of melena and purpuric spots. The absence of splenomegaly was observed in 20% patients (4/15) while 2 (13.3%) cases had lymphadenopathy. Hypocellular marrow was observed in 13% cases. Bright expression of CD20/CD22 along with CD25/CD103/CD123/CD11c was noted in all the patients of classical HCL. Aberrant expression of CD23 and CD5 was seen in 33% ( n =5) and 6.7% ( n =1) cases respectively. CD200 was positive in all the 5/15 cases tested. The case of HCL–v presented with very high leukocyte count and exhibited a CD103/CD11c+ and CD123/CD25- profile. BRAFV600E, mutation was present in all the four patients tested who included patients with a hypocellular marrow and absent splenomegaly. Conclusion: HCL has characteristic profiles, yet it may exhibit unusual clinical and immunophenotypic presentations. Perspicacious use of flow cytometry and BRAFV600E mutation analysis will aid in the diagnosis in unprecedented cases