[A case of orbital extranodal Rosai-Dorfman disease with increased IgG4 positive plasma cells].

The patient was a 52-year-old male. His right eye had been swollen for more than 6 years and he had once been diagnosed with "inflammatory pseudotumor of the right eye (lacrimal gland type)" and underwent surgical resection. He was admitted to the hospital due to the recurrence of swelling in the right eyelid accompanied by aggravated exophthalmos. The patient had high-myopia in both eyes, and there was a mass in the lacrimal gland area of his right eye. Imaging examinations showed relevant manifestations of the mass in the lacrimal gland area of the right orbit. During the operation, the characteristics of the mass in the right orbit were observed. Post-operative pathological examinations found that there were hyperplasia of histiocytes, lymphocytes, plasma cells, etc. in the diseased tissues. Immunohistochemical examinations had corresponding results. The result of gene rearrangement PCR detection was that no clonal amplification peaks of IgH and IgK were found. Finally, the patient was diagnosed with extranodal Rosai-Dorfman disease accompanied by an increase in IgG4-positive plasma cells. After 3-year follow-up, the patient was in good condition and there was no recurrence of the mass.