Abstract
BACKGROUND: Hypertransaminasemia associated with acute abdominal pain can be indicative of a broad spectrum of diseases, from benign to life-threatening. CASE DESCRIPTION: We present the case of a 72-year-old man reporting abdominal pain, unintentional weight loss and moderately elevated liver enzymes. Imaging revealed multisystem involvement including pancreas, biliary tract, thyroid, and salivary and lacrimal glands. Serological tests showed markedly elevated serum IgG4 levels. Histological findings revealed IgG4-positive lymphoplasmacytic infiltrates. In the absence of exclusion criteria, the patient met the 2019 EULAR/ACR classification criteria for IgG4-related disease (IgG4RD). DISCUSSION: IgG4RD is a systemic immune-mediated condition characterised by fibro-inflammatory infiltrates that can mimic malignancies or other autoimmune diseases. Its diagnosis requires an integration of clinical, radiological and histopathological data. CONCLUSIONS: This case highlights how non-specific findings, such as hypertransaminasaemia and abdominal pain, may hide rare but treatable conditions such as IgG4RD. Early recognition is crucial to initiate immunosuppressive therapy and prevent irreversible organ damage. LEARNING POINTS: Hypertransaminasaemia and abdominal pain, although common and non-specific findings, may conceal rare systemic conditions such as IgG4-related disease.Multisystem involvement together with markedly elevated serum IgG4 levels are key clues that should prompt consideration of IgG4-related disease.Early recognition of IgG4-related disease allows timely initiation of immunosuppressive therapy, which is essential to prevent irreversible organ damage.