Rare Clinical Symptoms in Hairy Cell Leukemia: An Overview

Simple Summary Diagnosis of hairy cell leukemia is based on the presence of hairy cells in bone marrow and peripheral blood as well as the characteristic immunophenotype. Moreover, in classic HCL, most patients present with a BRAF V600E mutation. The typical symptoms of classic hairy cell leukemia include pancytopenia, massive splenomegaly and increased risk of infection. However, rarer manifestations of HCL are occasionally reported, including cutaneous symptoms, bone infiltration, arthritis and central nervous system symptoms, as well as gastrointestinal tracts, heart, lungs, ocular involvement and other symptoms.Abstract Background: Hairy cell leukemia (HCL) is a rare indolent B-cell lymphoid malignancy. The majority of patients are asymptomatic and HCL is usually diagnosed incidentally during a routine blood cell count. In symptomatic patients, typical symptoms are related to pancytopenia and splenomegaly. In this review, we present rare clinical symptoms in patients with HCL. Methods: A literature search was conducted of PubMed, Web of Science and Google Scholar for articles concerning hairy cell leukemia, leukemia cutis, bone lesions, neurological manifestations, pulmonary symptoms, ocular manifestations, cardiac manifestation and rare symptoms. Publications from January 1980 to August 2024 were scrutinized. Additional relevant publications were obtained by reviewing the references from the chosen articles. Results: Extramedullary and extranodal manifestations of classic HCL are rare. However, leukemic involvement in the skin, bone, central nervous system, gastrointestinal tract, heart, kidney, liver, lung, ocular system and other organs have been reported.