Histologically confirmed immunoglobulin G4-related hypophysitis in an adolescent girl: a case report with review of literature

Hypophysitis is an extremely rare inflammatory condition in children that affects the pituitary gland and infundibulum. Immunoglobulin G4-related hypophysitis (IgG4-RH) is an IgG4-related disease (IgG4-RD) typified by the infiltration of IgG4-positive plasma cells into the pituitary gland, leading to fibrosis and damage. Although IgG4-RD was recently recognized as a defined clinical entity, pediatric cases of IgG4-RD are extremely rare. This report describes a histologically confirmed case of IgG4-RH in a 13-year-old girl. The patient became anorectic after several months of nonspecific symptoms such as headache and fatigue. Detailed examinations, including brain computed tomography (CT), did not detect any causes. However, repeated brain CT revealed pituitary enlargement. Further investigations identified an elevated serum IgG4 level (234 mg/dL, normal range: <118 mg/dL). Pituitary biopsy revealed increased IgG4-positive plasma cell counts in the anterior pituitary gland, fulfilling the diagnostic criteria for IgG4-RH. Steroid treatment dramatically improved her symptoms and reversed pituitary enlargement. A literature review identified 128 pediatric cases of IgG4-RD but only seven cases of pediatric IgG4-RH including our case. Although ophthalmic disease was the most common manifestation, broad clinical presentations were observed, even in pediatric cases. A slight female predominance was suggested in pediatric populations with IgG4-RD, whereas a male predominance was reported in adults. Pediatricians should consider IgG4-RH in the differential diagnosis when encountering patients with nonspecific symptoms because early diagnosis could improve the prognosis of pituitary function. Consequently, necessitating the diseases awareness.