Central diabetes insipidus in a cat with central nervous system B cell lymphoma

Abstract

A 6-year-old male neutered cat presented with blindness, lethargy, polydipsia, hyposthenuria and severe hypernatraemia. Central diabetes insipidus was demonstrated by means of a low measured anti-diuretic hormone (ADH) concentration in the face of hypernatraemia, and clinical response to supplementation with desmopressin. Magnetic resonance imaging of the brain showed a discrete mass in the region of the hypothalamus. The cat was euthanased and post-mortem histological examination demonstrated B cell lymphoma involving the brain, optic nerves, urinary bladder wall and diaphragm. To the authors' knowledge, this case report is the first to describe central diabetes insipidus caused by central nervous system lymphoma in the cat.

Fig 1.

MRI scan of the head of a 6-year-old neutered male domestic shorthair cat with CDI: post-contrast transverse slice at the level of the diencephalon. A well-defined space-occupying lesion (10 mm high, 10 mm wide) is evident in the hypothalamic—pituitary region (arrows).

Fig 2.

Necropsy specimen of the brain of a 6-year-old neutered male domestic shorthair cat with CDI: transverse slice at the level of the diencephalon. A well-defined space-occupying lesion (10 mm high, 10 mm wide) is evident in the hypothalamic-pituitary region (arrows).

Fig 3.

Hypothalamus of a 6-year-old neutered male domestic shorthair cat with CDI: the infiltrative neoplasm is causing lateral deviation of the third ventricle. The small inset at the upper right shows a higher magnification of the neoplastic B cells (HE).

Fig 4.

MRI of the brain of 6-year-old neutered male domestic shorthair cat with CDI, sagittal reconstruction at the level of the midline, with diagram showing the anatomic distribution of the circumventricular osmoreceptor organs in the rat for comparison. (Reproduced with kind permission of M McKinley.)