Sweat gland adenocarcinoma in a Sprague-Dawley rat

A female Sprague-Dawley rat weighing 230 g at 16 weeks of age showed swelling in the skin of abdominal region. The circumscribed swelling progressively increased in size measuring 4x2 cm and moving along with the skin. Histology of the mass showed acinar structures lined by cuboidal cells, cystic spaces filled with eosinophilic secretion and papillary projections lined by neoplastic cells with hyperchromatic nuclei. Based on histopathological features of the mass, it was diagnosed as sweat gland adenocarcinoma of skin, which is a rare tumour in rats.