Prescription of Blood Lymphocyte Immunophenotyping in the Diagnosis of Lymphoid Neoplasms in Older Adults.

Lymphoid neoplasms are a heterogeneous group of lymphoid neoplastic diseases with multiple presentations, and varying prognoses. They are especially frequent in older patients (OPs) and the atypism of this frail elderly population can make the diagnostic process even more difficult. Blood lymphocyte immunophenotyping (BLI) is essential in rapid noninvasive diagnosis orientation and guides complementary investigations. To our knowledge, BLI prescription has never been evaluated in OPs. We hypothesized that, when there is a suspicion of lymphoid neoplasm in the geriatric population, a BLI is performed in view of various clinical or biological abnormalities. This study aimed to: (1) describe the characteristics of hospitalized OPs having undergone BLI for suspected lymphoid neoplasm, (2) identify the causes leading to BLI prescription, and (3) identify the most profitable criteria for BLI prescription. This was a descriptive retrospective study on 151 OPs aged ≥75 years who underwent BLI over a 2-year period. Regarding BLI prescriptions, eight had lymphocytosis, constituting the "lymphocytosis group" (LG+), while the 143 others had BLI prescribed for reasons other than lymphocytosis (LG-), mainly general weakness and anemia. In the LG-, we compared OPs with positive and negative BLI results. The criteria found to be profitable for BLI prescription were lymphadenopathy, splenomegaly, lymphocytosis, and thrombocytopenia. BLI identified circulating lymphoid neoplasms (positive BLI) in 21/151 OPs, mainly marginal zone lymphoma and chronic lymphocytic leukemia. In polymorbid OPs, as per our study population, the diagnostic and therapeutic complexity explained in part the sole use of indirect and minimally invasive diagnostic techniques such as BLI.