Abstract
The diagnosis of chronic lymphoid leukemia (CLL) is essentially based on a blood smear and immunophenotyping by flow cytometry of circulating lymphocytes. Unusual locations of the disease can sometimes be observed. Here we report the case of a patient admitted for the management of pleurisy. The pleural effusion was lymphocytic exudate; histological examination of the pleural biopsy along with immunohistochemistry helped yield the diagnosis of secondary localization of CLL. The patient was transferred to the Internal Medicine department where chemotherapy was introduced.