The 471st case: duodenal ulcer, mucor infection, and elevated IgG4 / 中华内科杂志

Mucor infection is rarely reported in non-immunocompromised population, especially in isolated gastrointestinal tracts. IgG4-related diseases (IgG4-RD) have been recognized in recent years, but secondary causes of IgG4 elevation should be differentiated. We reported a young man with duodenal mass and ulcer and high serum IgG4 level. Histological biopsy of the mass revealed positive mucor mycelium and infiltration of IgG4 positive plasma cells. Serum IgG4 decreased to normal range after surgical resection and systemic antifungal treatment. This case suggests that isolated mucor mycosis infection can develop in the digestive tract and mimics as IgG4-related disease.