[Polyuria and polydipsia in a young boy--a case study (author's transl)].

A 13-year-old boy with a teratoma in the sellar region was presented. This patient had gradually developed polyuria and polydipsia since 2 years prior to the first admission. Endocrinological examination showed a marked reduction of pituitary function. Careful neuroradiological examinations including CT failed to show any mass lesion in the sellar and suprasellar regions but a marked increase of the width of the third ventricle. CSF examination revealed only a slight increase of cell count (lymphocytes). The patient was discharged with hormonal replacement therapy. Seven months later the patient developed visual disturbance and mental disorders. On the second admission, plain skull films showed enlarged sella and CT demonstrated a mass in the suprasellar region. Preoperative diagnosis was suprasellar germinoma. At surgery a teratoma, probably arising from the pituitary fossa, was totally removed. Histopathology of the tumor showed tri-dermal tissues including melanotic progonoma and germinoma. The authors presented various problems of the patient and their solving processes.