Successful medical treatment of an Aspergillus terreus mycetoma of the nostril/lip in a 16-year-old Fjord pony gelding with pituitary pars intermedia dysfunction.

This research paper recounts a unique case of a 16-year-old horse with a nonpainful tumor-like growth on its nostril, caused by a rare type of fungal infection. The horse was also diagnosed with an endocrine disorder, which may have made it more susceptible to the infection. The infection was successfully treated with medication and did not return after five months.

Objective and Overview

The research aims to report a rare case of cutaneous mycetoma in a 16-year-old gelding pony. The growth was caused by Aspergillus terreus, a fungus not typically known to cause such diseases in animals. The gelding was reportedly suspected of having Pituitary Pars Intermedia Dysfunction (PPID), which played a role in the case.

• The gelding was afflicted by mycetoma, which is a condition characterized by chronic and proliferative lesions of the skin or subcutaneous tissue.
• This condition is normally caused by the actinomycetes or filamentous fungi, hence the paper outlines an unusual case of the disease caused by the Aspergillus terreus fungus.

Methods and Results

The research adopted cytological and histopathological examinations to investigate the unusual growth on the pony’s nostril.

• The cytological examination revealed a marked pyogranulomatous inflammation, or an inflamed mass composed of neutrophils, a type of white blood cell, in the mass.
• A histopathological examination, which is a microscopic examination of tissue, confirmed that the mass was a fungal mycetoma.
• The causative agent was identified as Aspergillus terreus, a fungal organism, via a fungal culture examination.
• Further investigation with a TRH stimulation test confirmed the presence of PPID (commonly known as Cushing’s disease) in the pony. This condition may result in immune suppression, thereby increasing the animal’s susceptibility to fungal infections.

Conclusion

Despite the unusual nature of the infection and the complexity involved due to the presence of PPID, the treatment employed was successful.

• The pony was medically treated with pergolide medication for the PPID and given oral potassium iodide to combat the fungal infection.
• Notably, the treatment did not involve any surgical debridement or excision.
• The gelding responded well to the therapy, with no recurrence of the fungal growth after five months.
• The paper acknowledges this case as the first known instance of a cutaneous mycetoma caused by A. terreus in a horse to their knowledge.