Primary Effusion Lymphoma: Cytological Diagnosis of a Rare Entity--Report of Two Cases in HIV-Uninfected Patients from a Single Institution.

Background: Primary effusion lymphoma (PEL) is a Kaposi's sarcoma-associated herpesvirus (KSHV)-related large B-cell lymphoma often affecting immunocompromised adults. However, several cases in nonimmunocompromised elderly patients have been reported. It usually occurs as a massive, serosal effusion without tumoral masses and lymphadenopathies. The most frequent diagnostic materials are cytological smears, displaying large lymphocytes with variable morphological aspects but with a specific 'null-cell' phenotype associated with the expression of KSHV-related latency-associated nuclear antigen.

Cases: We report 2 cases of PEL that occurred in elderly, HIV-uninfected patients. In the first case, an 83-year-old man presented with severe dyspnea of 1 week duration. Radiological images documented pericardial effusion causing cardiac tamponade, without lymphadenopathies and solid masses. In the second case, an HIV-uninfected 94-year-old man was affected by anorexia, fatigue, shortness of breath and nonproductive cough. Radiological studies revealed bilateral pleural effusion, without evidence of abnormal lymphadenopathies and lung and/or pleural masses. Thoracentesis was immediately performed. Cytological evaluations of pericardial (first case) and pleural (second case) fluid effusion showed anaplastic and immunoblastic lymphocytes, respectively, expressing LCA/CD45, CD30 and KSHV.

Conclusion: Albeit rare, PEL should be kept in mind in the diagnostic algorithm of serosal cytological evaluation in elderly HIV-uninfected patients.