Unusual presentation of hairy cell leukemia: a case series of four clinically unsuspected cases.

Hairy cell leukemia (HCL) is characterized by pancytopenia and usually associated with massive splenomegaly, however the same may not be true in the clinical settings. Here we report four cases of HCL and all of them were without the classical clinical feature of splenomegaly. This is an observational study conducted between January 2013 to March 2014 where we could diagnose ten cases of HCL in Department of Hematology, All India Institute of Medical Sciences, New Delhi. Of these, four cases attracted attention because of absence of classical clinical features of HCL. Of the four cases, three presented with weakness/fatigability while fourth patient presented with recurrent respiratory tract infection. Surprising finding in these cases was absence of splenomegaly, both clinically and on imaging which demerit the suspicion of HCL clinically. All four had bi/pancytopenia and bone marrow examination coupled with immunophenotypic analysis confirmed the diagnosis of HCL. Three patients received chemotherapy with cladribine and achieved complete hematological remission. One patient did not receive chemotherapy due to poor general condition and was subsequently lost to follow up. To conclude, HCL can and do present without splenomegaly and this should not restrain one from suspecting HCL based on histomorphology which needs to be further confirmed by ancillary techniques. This finding in our series could be because these cases were picked early in their natural course of the disease. A high index of suspicion is essential for diagnosing and appropriately managing such cases.