Extra-adrenal paraganglioma of the equine orbit: six cases.
Abstract: At The Ohio State University from 1994-2006 six of seven horses evaluated for primary orbital disease were diagnosed with extra-adrenal paraganglioma (EAPG). The horses ranged in age from 14 to 24 years, with a mean of 16.8 years. Duration of clinical signs was 1.5 years to 5 years, with a mean of 2.8 years. Clinical signs varied, but all six had non-painful exophthalmus of the right eye. Five horses had complete ocular exams reported; three of five had decreased to absent vision, two of five had pale optic nerves, and in three of five, difficulty of retropulsion of the globe was noted. Diagnostic tests performed included complete blood count, serum profile, radiography, ultrasound, computed tomography, true-cut biopsy, ocular examination, guttural pouch endoscopy, oral examination, and physical examination. Expulsive hemorrhage during orbital exenteration occurred in all horses. In five of six cases, tumor extension through the orbital foramen was apparent intra-operatively. Histopathologic appearance of all surgically removed tissues consisted of sheets of polygonal cells with abundant lightly granular cytoplasm, round nuclei with vesicular chromatin, and rare mitoses. Neoplastic cells were arranged into small groups separated by a fine fibrovascular stroma. All six cases were chromagranin positive on immunohistochemical staining. Follow-up ranged from six months to six years, with a mean of two years. Four of the five horses that recovered from surgery had no apparent tumor recurrence in 6-48 months.
Publication Date: 2009-07-17 PubMed ID: 19604344DOI: 10.1111/j.1463-5224.2009.00706.xGoogle Scholar: Lookup
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Summary
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This study examines a series of cases of extra-adrenal paraganglioma (EAPG), a rare tumor, within the eye region of horses. Conducted by The Ohio State University, the researchers diagnosed six horses with EAPG out of seven examined for primary orbital disease between 1994 and 2006.
Case Overview
- The ages of the six horses ranged from 14 to 24 years, with an average age of 16.8 years.
- The duration of clinical signs varied between 1.5 to 5 years, the average being 2.8 years.
- All the horses showed similar clinical signs of non-painful exophthalmus (bulging of the eye out of its orbit) predominantly affecting the right eye.
- Complete ocular examinations reported a variety of symptoms in the horses including decreased or entirely absent vision, pale optic nerves, and difficulty in retropulsion of the eye globe.
Diagnostic Methods
- Several diagnostic tests were used in this study, such as a complete blood count, serum profile, radiography, and ultrasound.
- The study also employed computed tomography, true-cut biopsy, ocular and oral examination, guttural pouch endoscopy, and physical examination.
Results and Findings
- A common observation was that expulsive hemorrhage (sudden discharge of blood) occurred during the orbital exenteration (surgical removal of the eye and part of the orbit) in all the horses.
- In nearly all cases, it was noticeable intra-operatively that the tumor had extended through the orbital foramen (the hole in the skull through which the optic nerve passes).
- Examination of the surgically removed tissues revealed, amongst other observations, cells with lightly granular cytoplasm, round nuclei with vesicular chromatin, and scarce mitoses (cell divisions), arranged in small groups separated by a fine fibrovascular stroma (network of connective tissue).
- Immunohistochemical staining, a method used for identifying specific proteins in cells of a tissue section, showed chromogranin positivity in all the cases, indicating the presence of the tumor.
Follow-up and Recovery
- The follow-up period varied greatly, from six months to six years with an average of two years.
- Notably, four of the five horses that had recovered post-surgery did not demonstrate any apparent tumor recurrence in the follow-up period ranging from 6 to 48 months.
Cite This Article
APA
Miesner T, Wilkie D, Gemensky-Metzler A, Weisbrode S, Colitz C.
(2009).
Extra-adrenal paraganglioma of the equine orbit: six cases.
Vet Ophthalmol, 12(4), 263-268.
https://doi.org/10.1111/j.1463-5224.2009.00706.x Publication
Researcher Affiliations
- Animal Resource Facility, Kansas State University, Manhattan, KS, USA. tjmdvm1@yahoo.com
MeSH Terms
- Animals
- Eye Neoplasms / pathology
- Eye Neoplasms / veterinary
- Female
- Horse Diseases / pathology
- Horses
- Male
- Paraganglioma, Extra-Adrenal / pathology
- Paraganglioma, Extra-Adrenal / veterinary
Citations
This article has been cited 2 times.- Leonardi L, Rizac RI, Pettinari I, Mechelli L, De Feo C. A First Case Report of Orbital Extra-Adrenal Paraganglioma in Cat. Vet Sci 2021 May 14;8(5).
- Rodrigues FRN, da Silva Freire JM, Fidelis LAP, Pereira AABG, de Sousa DER, Wilson TM, Soto-Blanco B, de Castro MB. Paraganglioma of the Tongue in a Chow Chow Dog: A Comparison With the Human Counterpart and Literature Review. Front Vet Sci 2020;7:422.
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