Prevalence and pathology of neoplasia in the Spotted catfish, Arius maculatus (Thunberg, 1792) from the southeast coast of India

Abstract

This study investigated the spontaneous occurrence of neoplasms in spotted catfish, Arius maculatus, sourced from the Parangipettai landing stations, southeast coast of India. A total of 13,438 Arius maculatus (Spotted catfish) were examined for any signs of neoplasia, with 108 fish showing signs of neoplasia, resulting in an overall prevalence of 0.80 %. The gross and clinical symptoms revealed white, fleshy, and distended tumour masses located in the superficial fascia and subcutis. Necropsy examination showed evidence of local invasion; however, there was no evidence of metastasis to other visceral organs. The neoplasms were multinodular, with a regular, uniform distribution of stromal cells and giant cells. Atypical stromal cells contained round mononuclear cells arranged in a fascicular pattern. The appearance of the nuclei of the giant cells, which ranged from 6 to 47, was similar to that of the stromal cells; these resembled osteoclasts. Neoplastic lesions were histochemically positive for Masson’s trichrome, periodic acid-Schiff and argyrophilic nuclear organizer region. Based on the clinical, histological and histochemical findings, this neoplasia was diagnosed as a giant cell tumour. The present study provides the first record of neoplasia prevalence in Arius maculatus, offering baseline data for future biomonitoring and suggesting neoplasia as a potential indicator of environmental health in Indian coastal waters.