Abstract
A Gulf flounder (Paralichthys albigutta) presented in August 2014 at The Florida Aquarium for submandibular swelling and inappetence of approximately one week's duration. This animal was wild-caught from 2010 with no previous medical history. The animal was moved into a hospital tank to facilitate examination and medical management. Physical exam under sedation revealed a large, proliferative mass of the right submandibular region with a fistulous tract in the intermandibular space dissecting into the oral cavity with severe gingivitis. Infectious and neoplastic etiologies were top differentials. Previously reported oral masses in fish have been linked to Mycobacterium spp., such as Mycobacterium chelonae in farmed Russian sturgeon, and various neoplasms such as odontoma in pickhandle barracuda, ameloblastoma in Chinook salmon, and orocutaneous papillomas and carcinomas in brown bullheads.1-4 Radiographs of the oral cavity were unremarkable. Cytology revealed a large number of epithelial cells with no infectious organisms or malignancies identified. The animal was started on injectable danofloxacin, meloxicam, and vitamin B, and gavage feeding was initiated. Histopathology at the time of examination revealed reactive fibroplasia with no detectable etiology, and a deeper tissue biopsy was recommended.
One month later, the animal remained inappetent with little improvement of the mandibular swelling. The patient was anesthetized for surgical debridement, biopsy, and cultures. On evaluation of the oral cavity, the oral mass was found to be larger, occupied the majority of the right lower mandible, and extended to the left mandible along the gum line. The mass was aggressively debulked and left to heal by second intention. Repeat radiographs of the mandible at that time revealed no boney involvement. In-house acid fast stains were negative. Histopathology was consistent with gingivitis with no evidence of neoplasia or infectious etiologies. GMS and Fite's staining were negative for bacteria, fungi and acid fast organisms. Bacterial cultures were also negative. The animal was continued on danofloxacin, meloxicam, vitamin B, gavage feedings and metoclopramide was also initiated due to regurgitation.
Approximately five weeks later, the animal was in overall poor body condition, though swelling of the mandible had decreased significantly, and the surgical site appeared nearly healed. There were several firm regions noted in the epaxial musculature that were believed to be due to repeated injections. Due to concern for continued stress of handling, all treatments were discontinued. After one week, the animal started eating. Within one month, the oral cavity was healed with no active inflammation or lesions, and the animal was released back on exhibit. Though highly suspected, Mycobacterium infection was never confirmed in this animal, and it is possible the swelling was trauma-induced.
Acknowledgements
The authors wish to thank Susan Coy, Heather Dills, and the Husbandry staff of the Florida Aquarium; and Dr. Kathleen Hartman and Deborah Pouder from the Tropical Aquaculture Lab in Ruskin, Florida.
* Presenting author
+ Student presenter
Literature Cited
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