2020 Volume 53 Issue 12 Pages 976-984
A 45-year-old woman was referred to our department with a diagnosis of appendiceal cancer. Contrast enhanced CT revealed a 20 mm appendiceal mass that showed high FDG accumulation on FDG-PET/CT. Lower gastrointestinal endoscopy demonstrated a protruding lesion in the appendiceal orifice, but no neoplastic changes were found in biopsy specimens. Laparoscopic ileocecal resection was performed. Histopathological examination showed dense fibrosis and lymphoplasmacytic infiltration in the appendiceal mass. The number of IgG4-positive plasma cells was 112/HPF and the IgG4-positive/IgG-positive plasma cell ratio was 78.3%; therefore, IgG4-related inflammatory pseudotumor was suspected. However, there were some atypical points in this case for diagnosis of IgG4-related disease: focal inflammatory cell infiltration, the presence of neutrophilic infiltration and granulation tissue, and the absence of elevated serum IgG4 concentrations and other organ involvement. Further analysis of similar cases is needed to determine if this appendiceal lesion is truly IgG4-related disease.
