Xanthogranulomas are a rare, usually benign, nodular granulomatous inflammatory lesions ('foam-cell tumor') characterized by accumulation of lipoprotein-laden macrophages within epithelial cells.
Affected dogs often present with symptoms of lethargy, weakness, anorexia, vomiting, proprioceptive deficits, aggression and seizures.
Diagnosis is difficult as imaging with CT or MRI may not reveal a mass within the sella turcica, requiring hypophyseal biopsy or exploratory craniotomy.
Definitive diagnosis usually requires intraoperative or postmortem biopsy, verifying a xanthogranulomatous hypophysitis involving the sella turcica.
Histologically, these lesions have a characteristic appearance consisting of multinucleated giant cells, macrophages, and hemosiderin-laden macrophages with occasional lymphocytes and plasma cells admixed with large regions of cholesterol cleft deposition, fibrin, and prominent Rosenthal fibers.
A differential diagnosis would include lymphoma, hyperadrenocorticism, hypothalamic-pituitary trauma, dorsally expanding cysts, inflammatory granuloma, lymphocytic hypophysitis, congenital malformations such as empty sella syndrome and neoplasms such as craniopharyngioma, infundibuloma, pituitary adenocarcinoma and metastatic tumors such as metastatic mammary carcinoma, lymphoma, malignant melanoma and pancreatic carcinoma.
Treatment has not been reported with this disease, although hypophysectomy would empirically be effective, but would be associated with a poor prognosis due to .
- Zarfoss MK & Dubielzig RR (2007) Solid intraocular xanthogranuloma in three Miniature Schnauzer dogs. Vet Ophthalmol 10(5):304-307
- Cramer SD et al (2011) Sellar xanthogranuloma in a dog. J Vet Diagn Invest 23(2):387-390
- Foley C et al (2009) Hypothalamic-pituitary axis deficiency following traumatic brain injury in a dog. J Vet Emerg Crit Care (San Antonio) 19(3):269-274
- Meij BP et al (2012) Lymphocytic hypophysitis in a dog with diabetes insipidus. J Comp Pathol 147(4):503-507
- Goossens MM (1994) Diabetes insipidus in a dog with an αMSH-producing pituitary tumor. Vet Q 16(1):61
- Nielsen L et al (2008) Central diabetes insipidus associated with primary focal B cell lymphoma in a dog. Vet Rec 162(4):124-126