A Case Study of PSTPIP1-Associated Myeloid-Related Proteinemia Inflammatory Syndrome Masquerading as Inflammatory Bowel Disease.

Introduction: PSTPIP1-associated myeloid-related proteinemia inflammatory (PAMI) syndrome is a rare autoinflammatory disorder. Systemic inflammation, cytopenia, and skin lesions are classic features, accompanied by hypercalprotectinemia and hyperzincemia. Gastrointestinal manifestations such as colitis are infrequent. We present the first case in Thailand of PAMI syndrome presenting as refractory colitis. Case Presentation: A 23-year-old male presenting with adult-onset refractory colitis and a history of a teenage perianal abscess. Despite the relatively late onset of intestinal symptoms, the patient exhibited a complex clinical picture across multiple domains of inborn errors of immunity, including autoimmune hemolytic anemia, chronic neutropenia, hepatosplenomegaly, and severe cystic acne. Genetic testing revealed a PSTPIP1 mutation (E250K variant), and laboratory results showed pathognomonic hyperzincemia, confirming PAMI syndrome. Treatment with adalimumab led to significant clinical and endoscopic remission. Conclusion: PAMI syndrome should be considered a differential diagnosis in patients with atypical or refractory colitis, particularly when accompanied by systemic clues such as cytopenia, severe acne, or organomegaly. Serum zinc levels serve as a simple, cost-effective screening tool to facilitate prompt diagnosis and can function as a practical biomarker for monitoring the response to therapy.