Co-Occurrence of Craniopharyngioma and IgG4-Related Hypophysitis: An Epiphenomenon or a Mere Coincidence?

BACKGROUND: Craniopharyngiomas are sellar-suprasellar tumors that commonly present in children, with nonspecific symptoms of increased intracranial pressure, visual disturbances, and pituitary insufficiencies. Rarely has secondary hypophysitis (lymphocytic and xanthogranulomatous) been reported in association with craniopharyngioma. CASE DESCRIPTION: We have reported the case of a 16-year-old boy who had presented with gradually progressive diminution of vision in the right eye, intermittent headache, deceleration in growth velocity, and the lack of development of secondary sexual characteristics. Imaging revealed a sellar-suprasellar cystic lesion (3.8 x 3.1 x 3.5 cm) with calcifications. Laboratory tests revealed hypothyroidism, hypocortisolism, hypogonadism, and growth hormone deficiency. Craniopharyngioma was provisionally diagnosed. He underwent pterional craniotomy and gross total excision of the lesion. The excised tissue showed features of adamantinomatous craniopharyngioma, with a dense lymphoplasmacytic infiltrate and fibrosis involving the pituitary and dura mater. The lymphocytes were CD20-positive, and the plasma cells stained positive for IgG4 (50-60 IgG4-positive plasma cells/high power field). Consequently, the possibility of IgG4-related hypophysitis was considered in our patient. His serum IgG4 level was not elevated. Systemic involvement by IgG4-related disease was thoroughly ruled out. Fluorodeoxyglucose positron emission tomography/ computed tomography did not show any clinically significant hypermetabolism anywhere in the body. At the 3-month follow-up examination, his headache had resolved. However, he had not regained vision in his right eye. Repeat imaging studies showed no residual tumor tissue. CONCLUSIONS: The present case might represent the first ever report, to the best of our knowledge, of secondary IgG4-related hypophysitis due to craniopharyngioma, or it might, perhaps, be a chance association of these 2 entirely different disease entities.