Reactive lymphocytosis: a diagnostic dilemma in pleural effusion

  • Uma Kumar
  • Shelly Sehgal Specialist Pathologist, Dept. of Pathology, SDN Hospital, Delhi
Keywords: Effusion, Immunophenotyping, Lymphoma


Effusions containing numerous lymphocytes may be due to inflammatory processes, to non-specific reactions complicating other diseases or tolymphoid malignancies. In many cases it is difficult to make a differential diagnosis on morphological criteria alone. We present a case of 25 year old male who presented with cough and fever for one month along with left sided pleural effusion. Pleural fluid differential count showedlymphocytosis. Cytology smears showed the presence of large mononuclear cells with high N:C ratio,convoluted  nucleus and  prominent nucleolus. On immunophenotyping  it was proved to be a case of reactive T lymphocytosis. A single lymph node was also found in upper cervical region which showed epithelioid cell granulomas with ZN stain for AFB positive. To concludereactive lymphocytes are difficult to distinguish from lymphoma onmorphology alone. Diagnostic accuracy can be increased by history, clinical examination and the use of ancillary techniques like immunophenotyping or immunocytochemistry.


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Case Report