Work

Functional extra-adrenal paraganglioma in a cat

Year: 2026

Type: article

Abstract: Case summary: An 11-year-old, neutered male domestic shorthair cat was referred for diabetes mellitus and recurrent episodes of respiratory distress. Physical examination identified an abdominal mass, while routine laboratory testing was unremarkable. Cardiac evaluation revealed cardiomyopathy with a hypertrophic phenotype. Thoracic and abdominal CT identified a heterogeneous mass (5.6 cm) in the right caudal abdominal region, with normal-appearing adrenal glands. Urinary normetanephrine:creatinine and metanephrine:creatinine ratios were markedly increased (3164 µg/g and 271 µg/g, respectively), representing 51-fold and 15-fold increases compared with 13 clinically healthy control cats, strongly supporting the suspicion of a functional extra-adrenal paraganglioma. After phenoxybenzamine treatment, exploratory laparotomy was performed. Due to cardiovascular instability characterized by tachycardia and hypertension, tumor resection was not feasible; however, incisional biopsy samples were successfully obtained. Immunohistochemical findings confirmed the diagnosis of a neuroendocrine tumor, with immunoreactivity for chromogranin A and neuron-specific enolase. The absence of immunoreactivity for pan-cytokeratin (AE1/AE3) and the presence of S100 protein staining in sustentacular cells were consistent with an extra-adrenal paraganglioma. This is the first reported functional extra-adrenal paraganglioma in a cat with biochemical confirmation of catecholamine excess based on urinary normetanephrine:creatinine and metanephrine:creatinine ratios. Relevance and novel information: This case highlights the diagnostic utility of urinary metanephrines as a non-invasive tool for detecting catecholamine excess in cats. It also underscores the importance of considering paraganglioma in cats with episodic respiratory distress, hypertrophic phenotype cardiomyopathy, and the presence of an extra-adrenal mass.

Source: Journal of Feline Medicine and Surgery Open Reports

DOI: 10.1177/20551169261477489

Authors: Elber Alberto Soler Arias, Denner Santos Dos Anjos, Marianela Elisabeth Rendón, Sara Galac

Institutions: Universidad de Buenos Aires, Universidade Estadual Paulista (Unesp), Utrecht University

Language: English

Topic: Adrenal and Paraganglionic Tumors

Subfield: Surgery

Field: Medicine

Domain: Health Sciences

SDG: Good health and well-being

Open Access status: gold

Estimated APC paid: $700