Immunohistochemical analysis using cell block technique lead
Ovarian malignant lymphoma is a rare gynecologic disease and some patients show marked ascites, similar to those observed in advanced ovarian cancer. Although radical surgery improves the prognosis of ovarian cancer, treatment of lymphoma is based on chemotherapy, therefore, differential diagnosis is crucial.

A 65-year-old woman presented with a 1-month history of abdominal distention. Pelvic ultrasonography showed an 11-cm solid mass in the pelvis. Computed tomography and magnetic resonance imaging revealed bilateral (mainly left) ovarian masses in the pelvis and multiple metastases. Laboratory examination revealed that serum CA125 levels were elevated, suggesting the existence of advanced ovarian cancer.

To confirm the diagnosis, the ascites was removed via abdominocentesis. Although no malignant epithelial cells were observed, atypical lymphoid cells dispersed in the ascites were detected in the cytological analyses. Thus, for accurate diagnosis, Authorperformed re-abdominocentesis and immunohistochemical (IHC) analysis using cell block technique. Cell block analysis showed negative staining for CD3 and positive staining for CD20 in large atypical lymphoid cells, suggesting the existence of large B-cell lymphoma. Repeat blood examination showed that the serum sIL-2R level was elevated.

The author decided to perform a biopsy to make the final treatment decision. Histologically, the tumor demonstrated diffuse proliferation of large atypical lymphoid cells. The final diagnosis was diffuse large B-cell lymphoma.