In this study, three farmed Gilthead seabream exhibited tumor-like mass above the left pectoral fin. The mass measured 9 mm in length, 8 mm in width. Morphometrically, the mass was fleshy, raised, circumscribed, and rosy colored with grayish-white center. The affected fish showed poor growth with 280 g average body weight after 30 months rearing period. Internally, moribund fish exhibited pale kidney/liver, mottled spleen with remarkable visceral adhesions. The presumptive bacteriological and conventional biochemical assays revealed that fish were clinically infected with Photobacterium damselae subspecies piscicida. The histopathological picture of the tumor-like mass concurred with the standard cellular criteria of fibropapilloma. In brief, the epidermal papilloma was denoted by the remarkable hyperplasia of epidermis together with eosinophilic intracytoplasmic inclusion bodies and prominent mitosis in the hyperplastic cells. Ultimately, the proliferated dermal fibroblasts appeared whirling and elongated with spindle nuclei. Such pathological alterations have confirmed a typical form of dermal fibroma upon positively reacted with Masson’s trichrome stain. In the spleen, characteristic granulomatous reactions were observed especially in the area of melanomacrophage centers where the granuloma showed different developmental stages. The occurrence of skin tumors in farmed marine fish is an alarm for the critical impacts of the erratic usage of pesticides on marine aquaculture presenting a staggering prototype for the growing aquatic environmental pollution.

在这项研究中，三只养殖的金头海鲷在左胸鳍上方显示出肿瘤样肿块。测得的质量长9毫米，宽8毫米。从形态上讲，该团块肉质，凸起，外切，呈玫瑰色，中心为灰白色。养殖30个月后，受影响的鱼生长缓慢，平均体重为280克。在内部，垂死的鱼表现出苍白的肾脏/肝脏，斑驳的脾脏以及明显的内脏粘连。推定的细菌学和常规生化分析表明，鱼在临床上感染了淡色丹毒杆菌亚种piscicida。肿瘤样肿块的组织病理学图片符合纤维乳头瘤的标准细胞标准。简而言之，表皮乳头状瘤表现为表皮明显增生，嗜酸性胞内包涵体和增生细胞中明显的有丝分裂。最终，增殖的真皮成纤维细胞出现旋转并带有纺锤形核。这种病理改变已证实与马森三色染色剂阳性反应后的典型形式的真皮纤维瘤。在脾脏中，观察到特征性肉芽肿反应，特别是在肉芽肿表现出不同发育阶段的黑巨噬细胞中心区域。