Primary Gastrointestinal Follicular Lymphomas: A Prospective Study of 31 Patients with Long-term Follow-up Registered in the French Gastrointestinal Lymphoma Study Group (GELD) of the French Federation of Digestive Oncology (FFCD)

Background/Aims: Primary gastrointestinal follicular lymphomas (PGFL) are very rare. Our aim was to analyze the clinical features, management, and long-term outcomes in a prospective series of patients diagnosed with PGFL. Methods: All adult patients with PGFL, consecutively enrolled into the multicenter French study between 1990 and 2017, were evaluated and followed up prospectively after undergoing a complete work-up. Clinical, pathological and endoscopic features, as well as treatment outcomes, were analyzed. Results: Thirty-one patients (16 men, median age 62 years, range 33 to 79 years) with PGFL were included. The median follow-up was 92 months (range, 6 to 218 months). In the majority of patients (n=14), lymphoma was incidentally diagnosed during endoscopy. Otherwise, the most frequent circumstances of diagnosis were abdominal pain (n=7) and dyspepsia (n=5). The duodenum was the most common site of involvement (n=19) and multifocal localizations were seen in seven patients (22%). The most frequent first line strategy was surveillance applied in 22 patients (71%), of whom nine reached spontaneous, complete remission and 11 had stable disease. Seven patients (23%) received chemotherapy as first line treatment, and two underwent resection. Of seven patients who received chemotherapy, four achieved complete remission. In three patients, transformation into a high-grade lymphoma occurred. Conclusions: The diagnosis of PGFL is frequently fortuitous. The most common localization is in the duodenum. The disease has an indolent course and a good prognosis, however, rare cases of transformation into aggressive high-grade lymphoma may occur. An appropriate characterization and follow-up of these lymphomas is mandatory for their optimal management.