Abstract
A 7-year-old female Shih Tzu dog with lots of masses in the whole mammary gland was presented to the surgery department of the Veterinary Teaching Hospital in the Cheju National University. After surgical excision, all mammary samples were referred to Pathology Department of Veterinary Medicine. Grossly, masses were measuring up to $6.5{\times}4{\times}1cm$ and on cut surface of masses in right 1st, 3rd, 4th, 5th and left 1st, 3rd, 4th, 5th mammary masses were well delineated and firm, sulphur yellow, solid round to oval shape. Microscopically, most neoplastic sweat glands were severely proliferated in dermis and subcutis. Most tubules were lined by round to oval shaped epithelium with eosinophilic cytoplasm, hyperchromatic nuclei with high mitotic figures and severe central necrosis. The neoplastic epithelium also had PAS-positive diastase-resistant cytoplasmic granules, but negative with Perls iron stain. The left 2nd mass was well delineated, and had several dark brown areas and yellowish white glittered areas. Mass was well circumscribed with dense connective tissue. Neoplastic areas contained irregular sized mammary gland with papillary grown luminal epithelial cells in single or double cells layer with mitotic figures and small amounts of proliferated myoepithelial cells. Proliferated myoepithelial cells also produced slightly basophilic mucinous materials. Based on the gross, histopathologic and special staining characteristics, this dog was diagnosed as 90% of apocrine sweat gland aenocarcinoma and 10% mammary. complex adenomas in mammary masses. In our best knowledge, this is the first report for concurrent occurrence of apocrine sweat gland adenocarcinoma and mammary gland complex adenoma in mammary masses of the same dog.
