Rosai-Dorfman Disease: Report of a Case Associated with IgG4-Related Sclerotic Lesions
A 70-year-old male patient was diagnosed with autoimmune pancreatitis in May 2004. At that time, the serum IgG was mildly increased to 1,780 mg/dL (normal, 694 to 1,618 mg/dL). Until October 2009, he had been receiving steroid treatment, and he had a history of recurrence of autoimmune pancreatitis in November 2005.\nIn July 2010, a follow-up chest computed tomography was performed and showed abnormal findings with multiple enlarged lymph nodes in the bilateral mediastinal and both hilar areas as well as a small irregular nodular and patchy ground-glass opacity in both of the upper lobes and in the right lower lobe of the lung (). A physical examination showed a 2 cm skin nodule on his left forearm. The laboratory findings were as follows: IgG, 1,900 mg/dL (normal, 694 to 1,618 mg/dL); IgG4, 3.56 g/L (normal, 0.06 to 1.214 g/L); and serum amylase, 258 U/L (normal, 30 to 110 U/L).\nA biopsy of the skin nodule revealed that it was a subcutaneous lymph node (). This lymph node showed effacement of the lymph node structure with a dense lymphoid infiltrate with marked sinus expansion by histiocyte-like cells with intermediate to large round nuclei, vesicular chromatin, and ample cytoplasm containing small phagocytosed lymphocytes, red cells, and plasma cells (emperipolesis). The plasma cells were abundant both in the sinus and in the medullary cords. The immunohistochemical stain showed that the histiocytes were positive for CD68 and S-100 protein. Numerous IgG4-positive cells (approximately 200 IgG4 cells/high power field) were also noted. A bronchoscopic biopsy of the peribronchial lymph nodes was performed and showed a few non-caseating granulomas that were suspicious for dust granulomas with approximately 20 IgG4-positive plasma cells. The patient recovered with steroid therapy.