Introduction

The gastrointestinal tract is the most frequent site of extranodal lymphomas; however, primary intestinal lymphomas (1–4%) remain uncommon and represent a diagnostic challenge. The small bowel, given its length, location, and limited accessibility, is particularly difficult to evaluate using conventional techniques such as standard endoscopy or radiological imaging. As a result, advanced modalities including video capsule endoscopy (VCE) and enteroscopy have become indispensable for assessing suspected small-bowel disease. These tools allow high-resolution visualization, detection of subtle mucosal abnormalities, and targeted tissue sampling, thereby improving diagnostic accuracy in complex cases.

Clinical case

We describe the case of a 68-year-old woman undergoing surveillance for previously surgically treated oral melanoma. She had no gastrointestinal symptoms and no significant medical history that could suggest small-bowel pathology. A PET-CT scan performed during routine follow-up revealed abnormal radiotracer uptake in the small intestine, a finding not correlated with the abdominopelvic CT, which showed no evident lesions. Given the inaccessibility of the suspected segment by conventional upper or lower endoscopy, a VCE was performed. The study identified an exophytic, ulcerated, and infiltrative lesion located in the proximal jejunum.

To further characterize the finding, single-balloon enteroscopy was carried out. This technique made it possible to reach the lesion directly, enabling precise localization, endoscopic marking for potential future interventions, and collection of multiple biopsies. Additional samples were also obtained from an edematous area in the duodenum. Histopathological examination confirmed the diagnosis of primary intestinal follicular lymphoma (PI-FL).

Conclusions

PI-FL is a rare subtype of lymphoma (1–3.6%), most commonly arising in the duodenum and often demonstrating multifocal involvement throughout the small bowel. Endoscopically, it may present as nodular, polypoid, plaque-like, or ulcerated lesions. Because these abnormalities can be subtle and may not produce luminal distortion, they often remain undetected on standard imaging such as CT scans. This case highlights the diagnostic value of VCE and enteroscopy, which proved crucial for identifying and sampling a lesion that would otherwise have remained inaccessible.

These advanced endoscopic techniques are more sensitive and specific for evaluating small-bowel lymphomas, allowing accurate diagnosis and guiding appropriate therapeutic planning. Following confirmation of PI-FL, the patient was referred to Hematology for specialized management and longitudinal follow-up.