S6388 Dubious Danger – A Case Report of Gastric DLBCL Hiding in Plain Sight

Introduction: Diffuse large B-cell lymphoma (DLBCL) is a notably aggressive subtype lymphoma, often exhibiting extra-nodal involvement of the gastrointestinal tract. The stomach, small intestine, and ileocecal region are the most frequently affected sites. We present a case of a patient with stage III high-grade follicular lymphoma, subsequently transformed to refractory DLBCL with complications arising from splenic metastasis. Case Description/Methods: A 78-year-old woman with prior medical history significant for stage III high-grade follicular lymphoma, received 6 cycles of bendamustine and rituximab and mini-R-CHOP regimen presented with new-onset dysphagia and significant weight loss over 3 months. Two months prior, the patient presented with left upper quadrant pain, and splenomegaly was observed on imaging. Positron emission tomography (PET) scan at that time demonstrated increased uptake in an 8 × 8 cm splenic lesion (Standardized Uptake Value [SUV] 19) however, there was no uptake elsewhere. The pain was attributed to splenomegaly, and a splenectomy was planned and a exploratory laparotomy was performed. However, the procedure was aborted due to significant disease progression. The stomach cardia and fundus were densely adherent to the diaphragm, liver, and other underlying structures. Esophagogastroduodenoscopy (EGD) done later showed patchy white plaques in the esophagus, consistent with Candida. A large, ulcerated mass devoid of bleeding was seen in the gastric fundus. Biopsies were obtained which confirmed DLBCL. A repeat computed tomography (CT) scan done a month later, now revealed the lesion in the stomach. The patient was initiated on salvage chemotherapy. Upon follow-up, the patient reported improvement in her dysphagia, appetite and abdominal pain. Discussion: An intriguing aspect of this case is the absence of the gastric involvement on prior imaging despite ongoing symptoms of weight loss and abdominal pain initially attributed to splenomegaly. Unfortunately, gastric invasion was not suspected until laparotomy was performed. Follicular lymphoma can transform to DLBCL, characterized by its highly aggressive nature and typically exhibits a high SUV on PET scans. However, cases of DLBCL that are “invisible” on PET-CT, indicated by a low SUV, have also been reported. Currently, there is no surveillance guidelines for evaluating GI involvement in patients with DLBCL. This case highlights the utility of EGD in patients with upper GI symptoms and not responding to treatment, potentially avoiding more invasive procedures.