Abstract:
A 9-year-old sterilised female domestic short-hair cat was referred with a history of vomiting
and anorexia of 3 months’ duration. Biochemistry, full-blood counts, thoracic radiographs,
feline pancreatic-specific lipase, abdominal ultrasonography and feline immunodeficiency
virus/feline leukaemia virus (FIV/FeLV) SNAP tests had been performed. Mild hypochloraemia
and moderate hypokalaemia were evident on initial presentation. Abdominal ultrasonography
initially revealed unilateral renal nodules on the left side. These were subjected to fine-needle
aspiration and cytological evaluation. A neuroendocrine tumour was suspected, and biopsies
via midline coeliotomy were taken to confirm the diagnosis. Initial histopathology diagnosed
primary renal carcinomas or neuroendocrine neoplasia; however, the definitive diagnosis
became renal paragangliomas after immunohistochemistry and transmission electron
microscopy were performed. The cat was regularly monitored with serum biochemistry
parameters, blood pressure determinations, thoracic radiographs and subsequent abdominal
ultrasonography. Biochemistry, radiography and blood pressures remained normal over a
24-week follow-up period, while subsequent ultrasonography revealed tumour progression in
both number and size in both kidneys. Primary neuroendocrine tumours of the kidney are
frequently incorrectly diagnosed as other renal tumours such as renal cell carcinoma,
mesonephric tumours or undifferentiated carcinomas. This case report highlights the
importance of additional testing, including immunohistochemistry and transmission electron
microscopy, to obtain a definitive diagnosis of paragangliomas.
