gms | German Medical Science

Objective: At suprasellar area, numerous histologies arise including pituitary adenoma, meningioma, craniopharyngioma, sacroidosis, Langerhans cell histiocytosis. It is not easy to distinguish neurohypophyseal germinoma (NHG) from these lesions by neuroimaging. We tried to understand the MR characteristics and hormone impairment in NHG.

Methods: We analysed histology-verified 27 cases of NHG with MR information and endocrinological tests. The age distribution is 12-years to 27-year-old and 14 male 13 female cases are included.

Results: NHG are classified according to MR characteristics; type S includes thickened pituitary stalk with homogenous enhancement (n=10), type T indicates suprasellar to third ventricle mass (n=12) and type I shows intrasellar mass (n=5). The high signal of the posterior lobe by T1WI was absent in all cases, which indicates endocrinological diabetes insipidus. Type S resembles to neurohypophysitis but we can see distant satellite lesion in 70% of cases. Enhancement is weak and heterogenous as compared to hypophysitis. Type T resembles to craniopharyngioma or neurosarcoidosis. There are no calcification and a few small cysts if present. In Type I, normal pituitary cannot be identified and dural tail sign is present along with clivus. The cancellous bone of the clivus is tend to be invaded but cortical structure is relatively preserved. Endocrinological characteristics are observed such as hyperprolatinemia (Type S=T>I), diabetes incipidus (Type T>S>I), panhypopituitarism (Type I>S>T) and insulin tolerance test impairment (Type T>S>I).

Conclusions: There are 3 types of NHG on MRI, which corresponds endocrinological characteristics.