Examination of pericardial effusions by cytology and immunocytochemistry

Cytologic examination of pericardial effusions (PE) has been uncommonly reported in the literature. Fewer reports have studied the role of immunocytochemistry in diagnosis of PE. We described our experience, according to cytologic examination and immunocyto-chemical staining of PE.

Over a four-year period, 50 PE specimens from 36 patients were examined cytologically by Wright-Giemsa stain and/or Papanicolaou stain, at Tri-Service General Hospital. Immunocytochemical stainings were further performed to ensure the cell nature.

Eighteen of these patients had benign etiologies; the others suffered from malignant diseases. Sixteen cases, including eight benign and eight malignant, received pericardial biopsy for comparison. Commonly encountered cells in PE with any kind of etiology included neutrophils, lymphocytes macrophages and mesothelial cells. Cancer cells were additionally seen in malignant PE, but not in all cases with cancers. Furthermore, reactive mesothelial cells and macrophages were sometimes not easily distinguished from cancer cells, and reactive lymphocytes frequently mimicked hematopoietic malignancies. Further, the nature of small round tumor cells can hardly be ensured by morphologic examination only. Immunocytochemical studies were successfully used to solve these dilemmas in some suspicious cases.

This study showed that cytology together with clinical information and immunocytochemistry can achieve excellent sensitivity and specificity in identification of malignant PE. The use of immunocytochemistry can even ensure the nature of certain cancers such as small cell carcinoma and B cell lymphoma.