Atypical IgG4 related hypophysitis revealed by submandibular sialadenitis: a case report.

IgG4-related disease is a fibro-inflammatory multisystemic condition with lesions mimicking tumors. Involvement of the hypophysis is rare and the first case of IgG4-related hypophysitis was described in 2004. Typically, it is revealed by sellar mass effects, hypopituitarism, and diabetes insipidus. In the present paper, we report a case of IgG4-related hypophysitis revealed by submandibular sialadenitis. The subject was a 52-year-old patient presented with swelling of the submandibular gland. His complaints were decreased libido, anorexia, and weight loss for three months. Hormonal assessment found mild hyperprolactinemia, hypogonadotropic hypogonadism, and central hypothyroidism. Pituitary magnetic resonance imaging showed heterogeneous enlargement of the pituitary gland with diffuse gadolinium enhancement. The submandibular gland biopsy revealed submandibular sialadenitis with positive immunohistochemistry to IgG4. Diagnosis of IgG4-related hypophysitis was made based on Leporati criteria 2 and 3. Glucocorticoid therapy was prescribed for this patient, but without improvement of the pituitary function. In fact, the effectiveness of steroid therapy on the pituitary swelling is proven and already represents the fifth diagnostic criterion of Leporati. However, the improvement of the pituitary functions is uncertain. The present case illustrates an atypical presentation of IgG4-related hypophysitis without tumor syndrome or diabetes insipidus. Continuous monitoring of the pituitary function is needed during the long-term follow up given that improvement of the hormonal deficiencies is uncertain.