Abstract
Background : HHV8-negative common effusion lymphoma (HENCEL) is a type of malignant lymphoma arising in body cavities that differs both clinically and histopathologically from primary effusion lymphoma (PEL) ; their differential diagnosis is crucial in cytology specimens.
Case : A man in his 80s who was undergoing treatment for pulmonary adenocarcinoma presented with left pleural effusion. HENCEL was diagnosed by systemic examination and cytology. The tumor cells were smaller in size in the liquid-based cytology (LBC) specimen than in the conventional smear cytology, however, three-dimensional observation revealed irregularity of the nuclear membrane, which led to the diagnosis. The diagnosis of HENCEL combined with lung adenocarcinoma was confirmed at autopsy.
Conclusion : If cells suspected as belonging to malignant lymphoma are found in the pleural effusion, it is important to rule out secondary involvement of systemic lymphoma as well as PEL, when considering the possibility of HENCEL. Combined use of LBC with smear cytology can provide useful information for the diagnosis and contribute to improvement of the diagnostic accuracy of HENCEL.
