Gastric cancer or hodgkin lymphoma? Unraveling the diagnostic dilemma of primary gastric classical hodgkin lymphoma

Primary gastric classical Hodgkin lymphoma (PGHL) is a primary malignant neoplasm of the stomach, often clinically and radiologically mimicking gastric cancer. Immunohistochemistry is needed to diagnose such rare tumors. A 45-year-old male presented with abdominal pain, nausea, and unintentional weight loss. First investigations, such as endoscopic examination and biopsy, indicated that this was a case of non-Hodgkin lymphoma (HL). However, the immunohistochemistry (IHC) reinforced the classical HL with positive markers of CD15, CD30, PAX5, and MUM1, categorizing it as a mixed cellularity subtype. The patient underwent distal gastrectomy with Billroth II reconstruction and received four cycles of bleomycin, doxorubicin, vinblastine, dacarbazine chemotherapy, leading to complete clinical and radiological remission. PGHL, although rare, should be considered in the differential diagnosis of gastrointestinal malignancies. Immunohistochemistry plays a pivotal role in correct diagnosis, and a combination of surgery and chemotherapy is the ideal treatment strategy, as demonstrated in this case.