Anisakiasis is a parasitic disease caused by the consumption of raw or undercooked fish containing the third larval stage of anisakid nematodes. Safety in fish consumption from extractive fisheries is a challenge for public health authorities. This study presents the hematological analysis, necroscopic and histopathological examination of three Hoplias lacerdae parasitized by Anisakis spp. captured in an affluent of the Teles Pires River, in the municipality of Sinop, State of Mato Grosso, Brazil. At necropsy, intense parasitism was observed, characterized by free and adherent anisakid larvae in organs and mesentery. In the histopathological study, there were nephrotic alterations and hepatopathies, as well as the first report of the presence of Anisakis cyst adhered in the myocardium of Hoplias lacerdae. There was a correlation between the increase in the number of parasites and the circulating leukocytes, influenced by the number of neutrophils and eosinophils. However, other studies should be designed to elucidate the pathophysiological and epidemiological changes in Hoplias lacerdae by the parasitism of Anisakis spp., due to its socioeconomic importance, as well as the potential risk to public health.

This study presented a case report of a female of Oreochromis niloticus in the reproductive age. In the clinical analysis, the animal showed intense abdominal distension, severe cachexia, retraction of the eyeball and lethargic behavior. At the necropsy, it was observed the presence of neoplastic mass in the peritoneal cavity which presented smooth surface, circular appearance, soft consistency and reddish-blackened focal regions. There was the formation of multiple cysts, which presented a yellowish-green liquid content in the cut. In the histopathological examination, multiple dilatations were observed, filled with amorphous eosinophilic material with a delicate fibrocolagenous wall, as well as detachment of the granulosa and theca cells. The presence of macrophage infiltrates with hemosiderin pigments was also observed. The macroscopic and microscopic findings confirm the diagnosis of polycystic ovarian syndrome; however the causes of this cystic disease were not understood. KEY-WORDS:Cichlids. Ovarian cyst. Fish reproduction. Histopathology. RESUMOEste estudo apresentou um relato de caso de uma fêmea de Oreochromis niloticus na idade reprodutiva. Na análise clínica, o animal apresentava intensa distensão abdominal, caquexia severa, retração do globo ocular e comportamento letárgico. Na necropsia, observou-se a presença de massa neoplásica na cavidade peritoneal, apresentando superfície lisa, aspecto circular, consistência mole e regiões focais escurecidas de vermelho. Existia a formação de múltiplos cistos, que ao corte apresentavam um conteúdo líquido verde-amarelado. No exame histopatológico, foram observadas dilatações múltiplas, preenchidas com material eosinofílico amorfo com delicada parede fibrocolagenosa, além de descolamento das células da granulosa e da teca. A presença de infiltrados de macrófagos com pigmentos de hemossiderina também foi observada. Os achados macroscópicos e microscópicos confirmam o diagnóstico de síndrome do ovário policístico; no entanto, as causas desta doença cística não foram compreendidas. PALAVRAS-CHAVE:Ciclídeos. Cisto ovariano. Oreochromis niloticus. Reprodução em peixe.