A unique case of primary effusion lymphoma‐like lymphoma showing disappearance and recurrence of the body cavity effusion

Primary effusion lymphoma-like lymphoma (PEL-LL) is a rare B-cell lymphoma that the etiology remains unclear. We describe a case of PEL-LL with a pleuropericardial effusion. Diagnosis required long period of time as it followed a unique progress of disappearance and recurrence of the body cavity effusion. We finally had a diagnosis of B-cell lymphoma by the immunocytochemistry of effusion using the cell block procedure. Authors consider that it is valuable to actively try the cell block procedure at the time of the first drainage for early diagnosis, if the body cavity effusion due to the malignancy is suspected.