Severe upper gastrointestinal involvement in ulcerative colitis successfully treated with sequential therapy using intravenous tacrolimus and upadacitinib: a case report.

Ulcerative colitis (UC) is classically regarded as a disease limited to the colon; however, upper gastrointestinal (UGI) involvement has been increasingly recognized. We report a rare and clinically severe case of UC with marked UGI involvement that was successfully treated with tacrolimus and subsequently maintained with upadacitinib. A 19-year-old man presented with epigastric pain, diarrhea, and elevated inflammatory markers. Computed tomography demonstrated diffuse gastric wall thickening, whereas colonic involvement was relatively mild. Esophagogastroduodenoscopy revealed extensive erythema, spontaneous bleeding, and ulcerations in the stomach and duodenum, whereas ileocolonoscopy showed findings consistent with moderate UC. Histopathological examination of gastric and duodenal biopsies demonstrated dense inflammatory cell infiltration with crypt abscesses, supporting a diagnosis of UC-associated UGI involvement. The patient was refractory to high-dose corticosteroids and unable to tolerate oral therapy. Continuous intravenous tacrolimus was initiated, resulting in clinical and endoscopic improvement. Due to tacrolimus-related adverse effects, maintenance therapy was transitioned to upadacitinib, leading to sustained clinical and endoscopic remission. This case highlights the importance of recognizing severe UGI involvement as a rare UC phenotype and suggests that aggressive immunomodulatory therapy, including calcineurin inhibitors and Janus kinase inhibitors, may be effective in selected patients.