Frequency and histologic characterization of coelomatic neoplasms in koi Cyprinus carpio koi

Abstract

Koi carp presenting with coelomatic neoplastic lesions are of growing importance in Switzerland and elsewhere in Europe, as clinical diagnosis is usually difficult and prognosis is usually poor because of late recognition. To gain more information about this condition, between 2008 and 2012, 117 koi diagnosed with coelomatic tumours were included in this study. The nature and growth characteristics of these pathologic tissues were documented. Out of 117 koi, 48.9% (n = 57) were female; the ovary was the most often affected organ (35%, n = 41), and in 62.4% (n =73) of cases, the cells of origin were identified as stromal cells of the sex-cord and the tumours were identified as sex-cord stromal tumours. The characteristics of growth and histology showed that the majority of tumours were malignant.KEY WORDS: Koi carp · Neoplasm · Histopathology · Ovary · Testis · Sex-cord stromal tumour Resale or republication not permitted without written consent of the publisherDis Aquat Org 119: [219][220][221][222][223][224][225][226][227][228][229] 2016 To gain more information about the nature of neoplastic lesions in internal organs and the pathological features of these neoplasms, koi presenting with various abdominal neoplasms were examined between 2008 and 2012. Specifically, possible sex-specific differences, the organs affected, the tissue/cells of origin and the characteristics of neoplastic growth were investigated. MATERIALS AND METHODS Origin of samplesBetween 2008 and 2012, all koi carp with an enlarged abdomen, which were euthanized or died in our veterinary clinic, were examined pathologically. A standard necropsy was performed. Those fish showing a coelomatic mass suspected to be a tumour were included in this study, for a total of 117 animals. As there was no recurrence of tumour masses in the same animal, 1 tumour case always corresponds to 1 animal. If possible, the sex of the affected animal was recorded. Macroscopic changes of internal organs, including extent and appearance of the coelomatic mass (colour, surface, cut section and texture) were recorded in 62 cases. In all 117 cases, tissue samples of different representative areas were fixed and stored in 10% buffered formalin and sent for analysis to the Centre for Fish and Wildlife Health (University of Bern). These samples were identified histologically as coelomatic neoplastic lesions. This criterion was used for the final decision to include the animals in this study. Histopathology and immunohistochemistry (IHC)Formalin-fixed samples were paraffin-embedded and routinely processed. Three or 4 serial sections were prepared: the first sections were stained with haematoxylin-eosin (H&E), the remaining sections were used for IHC staining.As a basis to classify the neoplasms, criteria defined in the World Health Organization classifications for tumours in domestic animals (Kennedy et al. 1998, Head et al. 2003, Meuten et al. 2007) were used.Because of limited availability of antibodies working properly on our koi carp tissue, only an epithelia...

Ovarian mixed germ cell–sex cord–stromal tumour in a European seabass, Dicentrarchus labrax (Linnaeus, 1758)

“…In the present study, however, the two neoplastic components showed cytomorphological features in accord with pure dysgerminomas and granulosa cell tumours (GCTs) reported in fish by, but not limited to, Ishikawa and Takayama (1978) and Ott‐Knüsel et al. (2016).…”

“…Gonadal tumours are generally considered rare in teleosts, and most of the reported cases have been found in ornamental species (Ott‐Knüsel, Knüsel, Doherr, & Schmidt‐Posthaus, 2016). There are only three reports of spontaneously occurring neoplasms in European seabass Dicentrarchus labrax (Linnaeus, 1758), that is a gastric leiomyoma (Iaria et al., 2020), a multicentric lipoma (Marino, Chiofalo, Mazzullo, & Panebianco, 2011) and a skin fibropapilloma (Ramos & Peleteiro, 2003).…”

“…Specimens were routinely processed and four‐μm‐thick sections stained with haematoxylin and eosin (H&E) and periodic acid‐Schiff (PAS). Immunohistochemistry (IHC) of the ovary mass was carried out using mammalian primary antibodies, already successfully applied in fish (Iaria et al., 2020; Ott‐Knüsel et al., 2016; Marino, Germanà, & Panebianco, 2008; Romano et al., 2013; Sirri et al., 2010), against cytokeratin AE1/AE3 (AE1/AE3), calretinin, inhibin‐α (INHα), placental alkaline phosphatase (PLAP) and vimentin. Negative controls were performed by omitting the primary antibody and replacing it with 1% BSA + 10% NG1/20 in PBS.…”

“…Thus, a greater range of tissues should be routinely sampled, at necropsy, to undoubtedly rule out any other contributing cause. The number of published reports of MGSCTs in fish is too small for comparison; only a single case in a male Carassius carassius (Fregeneda‐Grandes, García‐Iglesias, Pérez Martínez, & Aller Gancedo, 2010) and one case in a hybrid Cyprinus carpio koi (data not shown) (Otta‐Knüsel et al., 2016) have been reported. In the present study, however, the two neoplastic components showed cytomorphological features in accord with pure dysgerminomas and granulosa cell tumours (GCTs) reported in fish by, but not limited to, Ishikawa and Takayama (1978) and Ott‐Knüsel et al.…”

Histological and immunohistochemical characterization of 17 gonadal tumours in koi carp (Cyprinus carpio koi)

“…Koi carp ( Cyprinus carpio koi ) are an ornamental variety of common carp frequently kept as pets in domestic ponds worldwide. They have a long lifespan, high economic value and high emotional value as pets due to their tame characters (Ott Knüsel et al., 2016). To date, only a few studies have reported the occurrence of tumours in koi carp, describing neoplasms of the skin, gills, liver, gonads and kidney (Ishikawa & Takayama, 1977; Knüsel et al., 2007; Ott Knüsel et al., 2015, 2016; Sirri et al., 2010, 2016, 2017).…”