# Plasmablastic lymphoma mimicking primary ovarian, tubal or peritoneal cancer: a case report and literature review

## TL;DR

A rare case of plasmablastic lymphoma in an immunocompetent woman was misdiagnosed as ovarian cancer but responded to a combination of chemotherapy and stem cell transplantation.

## Contribution

This case highlights the diagnostic challenges and treatment response in immunocompetent PBL with peritoneal involvement.

## Key findings

- PBL was misdiagnosed as carcinoma during intraoperative frozen sections.
- The patient achieved a 6-month partial response with chemotherapy, targeted therapy, and stem cell transplantation.
- Intraperitoneal biopsy and delayed cytoreduction are recommended to avoid unnecessary surgery.

## Abstract

Plasmablastic lymphoma (PBL), an extremely aggressive B-cell non-Hodgkin lymphoma, is known to be associated with immunosuppression. PBL with primary peritoneal or ovarian involvement is extremely rare. Here, we report a case of PBL in an immunocompetent woman, which involved the right ovary, peritoneum, cervical lymph nodes, and bone marrow.

A 42 year-old immunocompetent premenopausal woman presented with abdominal dullness and distension. Imaging studies revealed the presence of ascites, ovarian mass, peritoneal seedings, and generalized lymphadenopathy. Laparoscopic biopsies of the right adnexal tumor, omental cake, and peritoneal seedings were performed. Poorly differentiated carcinoma was suggested from initial intraoperative frozen sections. The conclusive histological and immunohistochemical diagnosis was however that of PBL. Bone marrow involvement was also confirmed. The patient was treated with dose-adjusted etoposide, prednisone, vincristine, cyclophosphamide, and doxorubicin plus daratumumab and bortezomib. Haploidentical peripheral blood stem cell transplantation (halpo-PBSCT) was performed to achieve better disease control. The patient showed sustained partial response for six months.

The diagnosis of immunocompetent PBL with intraperitoneal spread before surgery and during intraoperative cryosections remains challenging. Intraperitoneal biopsy and delayed cytoreduction can prevent unnecessary tumor resection. However, a definitive treatment modality is yet to be established. Our patient responded to chemotherapy plus targeted therapy, followed by halpo-PBSCT, leading to a 6-month partial response. Our experience provides additional information on pretreatment evaluation and therapeutic considerations for patients with PBL.