[Clinicopathological diagnosis of IgG4-related disease: report of eight cases].

OBJECTIVE: To evaluate the clinical and pathological features of IgG4-related disease (IgG4RD).

METHODS: The clinical data, laboratory profiles, radiological, pathological and therapeutic features of eight cases of IgG4RD were analyzed. This cohort included two cases of common bile duct and partial hepatectomy specimens, two of submandibular gland excision specimens, one from lung biopsy specimen, one from open lung biopsy specimen, one from renal biopsy specimen, and one from renal excision specimen. In all cases, adequate lesion tissues were obtained. They were paraffin embedded, HE stained, and additional special stains and immunohistochemistry performed (MaxVision method).

RESULTS: This series consisted of five males and three females, with a mean age of onset of 60 years. Five cases were suspected to be malignant pre-operatively, including two cases suspected of common bile duct carcinoma, two suspected of salivary gland tumor, and one suspected of renal pelvic carcinoma. Elevated serum levels of IgG4 and IgE were detected in five cases and eosinophilia in four cases. Multi-organ involvement was noted in four cases. The major histopathological features associated with IgG4-RD were: dense lymphoplasmacytic infiltrate, with lymphoid follicle formation. Extensive eosinophilic infiltrate (> 10/HPF) was seen in four cases; fibrosis that was arranged at least focally in a storiform pattern was also noted. The numbers of IgG4 positive plasma cells were > 20-50/HPF, while the IgG4 to IgG ratio was more than 40%. Obliterative phlebitis was present in four cases. Other pathological changes such as necrotizing vasculitis or lymphoma were not found. Five patients responded well to glucocorticoids.

CONCLUSIONS: IgG4RD has relatively specific histopathological features; accurate evaluation of the absolute and relative number of IgG4 positive plasma cells in lesional tissue, combining with clinical examination and exclusion of other causes of elevated IgG4, allows the diagnosis of IgG4RD. IgG4RD has complicated clinical manifestation, and glucocorticoids therapy is efficacious.