PMC4360849_01
Hypertonic saline infusion test. 5% hypertonic saline was infused at 5 mL/kg/min for 2 hours (8 am to 10 am). At 10 a.m., 1 unit of vasopressin was infused. During the infusion, urine output and osmolality and plasma sodium were measured every 15 min.
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To evaluate the function of his posterior pituitary hormone, we carried out hypertonic saline infusion test, which showed that his urine osmolality did not exceed above 300 mOsm/kg during hypertonic saline infusion (8 a.m. to 10 a.m.) and his urine output was decreased and his urine osmolality was increased after the vasopressin infusion (10 a.m.) (Fig. 1).
Pituitary MRI and abdominal CT pre- (A, C, E) and post- (B, D, F) replacement of hydrocortisone. After the treatment, almost all renal nodules (white arrows) disappeared and the pituitary stalk was shrinking.
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MR images showed that the pituitary stalk (Fig. 2A) exceeded more than 2.5 mm and became thickened. Multiple nodules in bilateral kidneys were pointed out in the abdominal CT (Figs. 2C, D, E, and F). The follow-up images showed that almost all renal nodules disappeared and his pituitary stalk was shrinking 3 months and 5 months after the treatment, respectively (Fig. 2B).
Histopathological features of the renal nodules specimen. A, B: Hematoxylin and eosin staining showing remarkable infiltration of lymphocytes and plasma cells. Magnification: A x 40, B x 100. C, D: Immunohistochemistry for IgG (C) and IgG4 (D)-positive plasma cells. The comparison revealed that the ratio of IgG4 to IgG-positive plasma cells was more than 80%. Magnification: C,D x 200.
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Histological examination showed increased IgG4-positive plasma cells (Fig. 3).