Surgical removal of a seminoma from a black sea bass

Cytology of a seminoma in a koi (Cyprinus carpio): a rapid diagnostic tool

Koi(Cyprinus carpio) is an ornamental variety of common carp frequently kept as pets. Given their long lifespan, neoplasia, albeit uncommon, may occur in these animals, and only a few studies have faced their cytological diagnosis. In the present case, a koi carp was referred to the clinicians due to coelomic swelling. The carp underwent surgery, which revealed an enlargement of both testes. Testicular samples were cytologically and histologically examined. The lesion was diagnosed as a seminoma since it was composed of round, large, atypical, and often multinucleated cells with round central nuclei and moderate cytoplasm. These tumors had the same appearance as seminomas in mammals and should be considered among differential diagnoses when coelomic swelling occurs in koi carp. Seminomas in koi carp are diagnosed histologically, but cytology, a rapid and cheap exam executable in all veterinary clinical facilities, could be a relevant preliminary diagnostic tool that may influence the entire diagnostic process.

Implications of comparative ventral body wall histology on selection of abdominal surgical approach and closure in 12 species of fish

A ventral midline surgical approach for fish celiotomy is commonly performed in veterinary clinical medicine and research, although the relevant ventral body wall anatomy of many fish species is not well documented. Histological evaluation of tissue samples from the ventral body wall of 12 fish species was performed to provide a reference for surgical approach and closure decisions. The width between muscle bundles running parallel to the long axis and total thickness of tissue layers varied among species. An appreciable space between longitudinal muscles of the ventral body wall and a lack of muscle, vessels and nerves on midline in all species examined supports recommendations of ventral midline incisions to spare important structures. Dense connective tissue consistent with an aponeurosis between musculature along the ventral body wall was not observed in any species evaluated. Connective tissue was concentrated within the dermis of all species evaluated, with an additional layer of collagen along the coelomic membrane in Russian sturgeon Acipenser gueldenstaedtii, koi Cyprinus carpio, goldfish Carassius auratus, black drum Pogonias cromis, black seabass Centropristis striata, tomtate Haemulon aurolineatum and scup Stenotomus caprinus. A sufficiently wide space on ventral midline for practical targeting during the surgical approach is present in A. gueldenstaedtii, C. carpio, striped bass Morone saxatilis, H. aurolineatum, P. cromis, rainbow trout Oncorhynchus mykiss and brown trout Salmo trutta. Sand perch Diplectrum formosum, C. auratus, S. caprinus, grey triggerfish Balistes capriscus and black sea bass Centropristis striata have a negligible space between longitudinal muscles on midline. The variation in ventral body wall structure observed in this study helps inform surgical decision making for celiotomy incision and closure in these species.

Spontaneous neoplasia in captive syngnathid species: A retrospective case series (2003-2014) and literature review

Syngnathidae (seahorses, pipefish and seadragons) are charismatic species commonly kept in commercial aquaria, but published literature on syngnathid diseases is limited and immunohistochemical techniques not routinely employed. A retrospective review of 2,541 syngnathid submissions received between March 2003 and October 2016 identified 18 neoplasms including germ cell tumours, exocrine pancreatic and intestinal carcinomas, chromatophoromas, and single cases of lymphoma, thyroid and renal carcinoma, swim bladder and pituitary adenoma. Big-bellied seahorses accounted for 19% of submissions, but 50% of neoplasms were diagnosed in this species. This study includes the first reported cases of germ cell tumours, chromatophoroma, thyroid carcinoma and pituitary adenoma in Syngnathidae and the first reports of neoplasia in pipefish species. Out of nine commercial antibodies trialled for immunohistochemical characterization of neoplastic tissue, only pan-cytokeratin proved cross-reactive. Electron microscopy was performed in four cases. Tumours should be considered as differential diagnosis in cases with buoyancy issues, debilitated or emaciated animals, and may predispose to secondary infections. This study highlights the value of histopathological disease surveillance for commercial aquarium settings.

Fish Oncology: Diseases, Diagnostics, and Therapeutics

The scientific literature contains a wealth of information concerning spontaneous fish neoplasms, although ornamental fish oncology is still in its infancy. The occurrence of fish neoplasms has often been associated with oncogenic viruses and environmental insults, making them useful markers for environmental contaminants. The use of fish, including zebrafish, as models of human carcinogenesis has been developed and knowledge gained from these models may also be applied to ornamental fish, although more studies are required. This review summarizes information available about fish oncology pertaining to veterinary clinicians.

A veterinary guide to the fish gastrointestinal tract

For veterinarians to better understand aquatic animal health, the most basic veterinary foundation begins with understanding piscine anatomy and physiology. General observations of fish behavior, anatomy, and food apprehension can provide more valuable diagnostic information than advanced laboratory testing alone. This article highlights anatomic differences of fish species occupying different environmental niches, using a case to show the use of modern veterinary diagnostics, and introduces additional topics in piscine gastroenterology related to toxins, nutrition, probiotics, and infectious diseases.

Geriatric veterinary care for fish patients

There is little evidence-based research and scientific literature available for providing geriatric care for fish patients. Fish can have tremendous longevity. Although the average life span for most fish species can be only a few days to weeks for the beginning hobbyist, it is becoming more common for clients to have animals for several decades with the advent and continued development of improved life-support systems, husbandry, water quality additives, and fish nutrition. This article discusses fish longevity for several popular species, addresses environmental quality issues for geriatric patients, and provides information on the most common challenges, from a veterinary perspective, to maintain fish over the years.

Diagnostic cytology of fish

Cytology is an essential part of a diagnostic workup in cases of aquatic animal diseases. It is simple to perform, inexpensive, and can yield quick and valuable results. External parasites, bacterial and fungal diseases, and gastrointestinal infestations are easily determined with wet mount cytology. Because of the relatively small number of nonlethal diagnostic techniques available for aquatic species, cytologic testing should be considered in every case. Early diagnosis can lead to more effective treatment plans, ensuring a better prognostic outcome in our patients.

Surgical removal of an ovarian tumour in a koi carp (Cyprinus carpio)

Ultrasonography, radiography and exploratory coeliotomy were used to diagnose and treat a large intracoelomic neoplasm from a female koi carp (Cyprinus carpio) presented for abdominal enlargement of several months duration. Feed was withheld for 1 week immediately prior to surgery and the fish was sedated with isoeugenol (AQUI-S) at a dose rate of 10 mL/L to facilitate diagnostic imaging techniques. Surgical anaesthesia was induced by adding tricaine (MS-222) 50 mg/L to the water and an exploratory coeliotomy and tumour removal was performed. The fish was allowed to recover in fresh water at 18 degrees C and salt was added slowly to the water over a period of 1 hour to a concentration of 5 g/L This concentration was maintained in a recovery pond for 1 week postoperatively. Enrofloxacin was administered intramuscularly (10 mg/kg) immediately, 3 days and 1 week postoperatively. A diagnosis of undifferentiated ovarian carcinoma was made on the basis of the histological appearance of the neoplasm and immunohistochemical staining.

Neoplasia in fishes

Similar to higher vertebrates, neoplasia is not an uncommon disease in fishes, which are the largest group of vertebrates. However,neoplasia in fishes is generally a benign condition with relatively few exceptions of malignant disease. The objective of this discussion is to provide an overview of neoplasia and the various neoplastic disease conditions in fishes according to organ system,including the few neoplasms of species that are familiar to the aquatic animal or exotic animal practitioner. The discussion also considers the various nonneoplastic lesions in fishes that may be confused with neoplasms, and treatment of neoplastic disease in fishes that is generally restricted to surgical intervention.

Use of pneumocystoplasty for overinflation of the swim bladder in a goldfish

A Ryukin goldfish was evaluated because of a 6-month history of progressive abdominal distention and positive buoyancy. Overinflation of the swim bladder was diagnosed, and the fish was anesthetized with tricaine methanesulfonate. Archimedes' principle was used to determine the volume of swim bladder that was removed surgically. The caudal swim bladder was exteriorized through an abdominal incision and 2 surgical clips were placed across it to limit its size. After surgery, the fish remained in a state of negative buoyancy in sternal and lateral recumbency on the bottom of the tank. Sutures were removed 15 days after surgery, but the fish died 24 days after surgery. A full necropsy could not be performed because of autolysis of the tissues, but the surgical clips and the swim bladder appeared unremarkable. Pneumocystoplasty may be a viable treatment for this condition.