Endoscopic Diagnosis and Clinical Course of Isolated Upper Gastrointestinal Amyloidosis: A Retrospective Observational Study.

Objectives: Early diagnosis of upper gastrointestinal (UGI) amyloidosis and the establishment of appropriate treatment and follow-up strategies remains challenging. This study aimed to elucidate the endoscopic characteristics and clinical courses of patients with isolated UGI amyloidosis. Methods: We retrospectively reviewed 11 patients diagnosed with isolated UGI amyloidosis at Chonnam National University Hospital and Chonnam National University Hwasun Hospital. None of the patients exhibited systemic involvement or multiple myeloma. Clinical data, including endoscopic features, presenting symptoms, and outcomes such as disease progression and mortality, were analyzed. Results: The cohort included seven males (63.6%) and four females (36.4%), with a median age of 72 (37-82) years. Isolated gastric amyloidosis was identified in four patients, and five patients had disease confined to the duodenum. Two patients (18.2%) presented with gastric or duodenal involvement. Endoscopic findings were heterogeneous, with diffuse yellowish linear lesions being the most frequently observed in four patients (36.4%). Histopathological analysis revealed AA amyloidosis in three patients, whereas five patients exhibited only amorphous deposits without amyloid A, amyloid P, or light chains. Six patients (54.5%) were asymptomatic at diagnosis, whereas gastrointestinal bleeding was observed in two patients (18.2%). Only one patient (9.1%) experienced disease progression that necessitated systemic chemotherapy. The mean follow-up duration was 20 months, and the 3-year mortality rate was 9.1%. Conclusions: Isolated UGI amyloidosis is a heterogeneous condition that can be easily misdiagnosed. Familiarity with the characteristic endoscopic features and natural disease course is essential for appropriate management.