Malignant pituitary chromophobe adenoma in an infant accompanying diabetes insipidus.

This report deals with a 1.5-year-old male infant terminating in viral pneumonia and "diabetes insipidus". The autopsy revealed malignant pituitary chromophobe adenoma, invading the wall of the third ventricle, extending to the periventricular-, dorsomedial- and ventromedial area, skipping to the lateral area adjacent to the optic nerve, and permeating into the subarachnoid space of the cerebrum. At the onset of disease polydypsia and polyuria were marked followed by interstitial pneumonia with high fever, and later generalized tonic convulsion terminated in death. This case is peculiar in at least two respects. Firstly, this is the youngest reported case of malignant chromophobe adenoma. Secondly, the manifestation of diabetes insipidus is rare in chromophobe adenoma. The malignant adenoma probably occurred from the primitive gland rest of chromophobe cells in the posterior lobe becoming malignant during the course of growth development and destroyed the cells of the posterior lobe, resulting in diabetes insipidus.