Pleural Lymphoma

Pleural effusion is a common finding in patients with non-Hodgkin lymphoma. Thoracoscopy is one of the important diagnostic means, especially when there is negative result from fluid cytology. We report a case of pleural involvement with recurrent diffuse large B-cell (DLBC) lymphoma diagnosed by thoracoscopic pleural biopsy.

A 57-year-old man presented with progressive dyspnea and decrease in exercise tolerance. He was a known case of DLBC lymphoma, diagnosed in 2013. He had been treated with a chemotherapy regimen of R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisolone) and had achieved complete remission. However, the disease relapsed within half a year after stoppage of chemotherapy, when he noticed a left jaw mass. The diagnosis was confirmed by a surgical biopsy. Another regimen of R-ICE chemotherapy (rituximab, ifosfamide, carboplatin, and etoposide) was prescribed, and the mass resolved.

Three months later, he complained of progressive dyspnea. A chest x-ray revealed a large left-sided pleural effusion. Diagnostic left pleural tapping and closed pleural biopsy revealed only the presence of lymphocyte-predominant exudative effusion, but no definite diagnosis could be made. Medical thoracoscopy was then performed under conscious sedation. During examination, multiple discrete yellowish pleural nodules of about 2 cm in size with smooth contour were seen clustered over the visceral pleura at the costophrenic angle. Biopsy was performed, which confirmed the diagnosis of pleural DLBC lymphoma (Figs. 1, 2).

FIGURE 1: Pleural nodule (arrow) under medical thoracoscopy.

FIGURE 2: Microscopy. A, Pleural infiltrate comprising large lymphoid cells with irregular nuclei and several prominent nucleoli (H&E stain). B, Atypical large lymphoid cells showing expression of pan-B-cell antigen (CD20). Immunohistochemical stain for CD20 (26). C, Large lymphoid cells that are positive for BCL2 as well. Immunohistochemical stain for BCL2 (Nikon Eclipse Ni-U with Plan Apo ×60 objective, C-mount 0.7, and 23 CCD Camera with 5 mega pixels).

DISCUSSION

Pleural effusion is a common finding in patients with non-Hodgkin lymphoma, with a reported incidence of 16% to 20%; among them 60% account for DLBC lymphoma.^1,2

Lymphomatous pleural effusions are usually exudative. However, transudative effusion can occur from heart failure or venous compression. Chylothorax has also been documented due to lymphomatous invasion of the thoracic duct.^1,3

Pleural involvement could be unilateral or bilateral, with left side more than the right side.²

Cytologic examination is useful in diagnosing lymphoma-associated pleural effusion. However, the false-negative rate might be high. In 1 review, positive yield of cytologic examination ranged from 14% to 88%. This might be due to the limited tendency of different lymphoma types to seed into the pleural fluid.³ Flow cytology and immunophenotyping are shown to enhance the diagnostic yield, with the additional advantage of identification of subtypes of lymphoma. The efficacy of closed pleural biopsy is limited by the fact that malignant cells might be scattered in the pleural cavity, leading to negative result. Thoracoscopy allows direct visualization of the pleural cavity and identification and biopsy of lesions, and it is useful in undiagnosed cases.

The gross morphologic appearance of pleural lymphoma is varied, ranging from diffuse involvement to nodule or mass. Here we describe one of the presentations, which appears in the form of multiple smooth yellowish discrete nodules, mainly over the costophrenic angle.

It is not known whether in the past the presence of pleural effusion in lymphoma was of prognostic significance. However, in recent literature, pleural effusion is regarded as one of the adverse prognostic factors. One hypothesis is that the presence of lymphoma cells in the pleural fluid might signify the ability of spread of the lymphoma.^2–5