Primary gastric T-cell lymphoma presenting with perforation: a case report and review of the literature.

Primary gastric T-cell lymphomas (PGTL) are exceedingly rare with an estimated incidence of 0.0091 per 100,000 person-years, affecting mainly elderly males. PGTL can present with a variety of gastrointestinal symptoms, but patients only rarely present with perforation. We report the case of a 68-year-old male who presented to the emergency department with a history of chronic abdominal pain that was localized to the epigastrium over the last few days. Computed tomography (CT) identified pneumoperitoneum. Exploratory laparotomy revealed gastric antral perforation. Histologically, perforation margins were diffusely involved by large pleomorphic lymphoma cells with multilobated nuclei and focal anaplastic morphology. Immunohistochemically, neoplastic cells were positive for CD3 (partial), CD4, CD5, CD7, CD43, CD45, BCL2, and BCL6 (dim). The neoplastic cells were negative for CD1a, CD2, CD8, CD10, CD20, CD21, CD23, CD30, CD34, CD56, ALK1, TdT, lysozyme, CXCL13, ICOS, PD1, myeloperoxidase (MPO), human herpesvirus-8 (HHV-8), and keratin. Ki-67 showed a proliferation rate of 80-90%, and in situ hybridization was negative for Epstein-Barr virus. Polymerase chain reaction (PCR) of the T-cell receptors gamma (TRG) and beta (TRB) demonstrated monoclonal peaks. Quantitative PCR for HTLV-1 integration was negative. The diagnosis was peripheral T-cell lymphoma, not otherwise specified, stage IV, consistent with primary gastric lymphoma. To better understand this neoplasm, we performed a comprehensive English language literature review, retrieving clinical, pathologic, immunophenotypic, and molecular data when available, and discussed the most relevant features for diagnosis and classification using the 5th edition of World Health Organization, as well as prognostic features and outcomes of this lymphoma.