Occurrence of neoplastic lesion in spotted catfish (Arius maculatus Thunberg, 1792) from the estuarine environment, southeast coast of India

Abstract

Present study reports the neoplastic lesions in Arius maculatus (Spotted catfish), widely distributed species across the coastal waters of India, a phenomenon previously underreported for this species. A wild adult female Arius maculatus from the Vellar estuary, India, was found with a significant tumor. The gross morphology revealed a mass of fleshy, tumorous outgrowth located ventrally near the mandibular region, measuring approximately 2.5 cm × 2.6 cm × 2 cm, and presenting as an irregular, reddish-white. Comprehensive pathological examination, including histological analysis, revealed that the tumour exhibited aggregated eosinophils and anucleated inflammatory cells in areas of necrosis. Notably, no metastasis was detected, and no internal organs showed abnormalities. This report concludes that this is the first case documenting neoplastic lesions in Arius maculatus, histopathologically diagnosed as eosinophilic coagulative necrosis that may arise from tissue damage, contributing to the understanding of fish pathology and highlighting the need for further research to elucidate the environmental or genetic factors influencing tumour development in this species.