Sectioning reveals a large, well-circumscribed, partly encapsulated, pale white tumour 33x24x24mm with areas of necrosis and cystic formation. The tumour is situated 1mm from the medial, posterior and superior margins, 8mm from the lateral margin and >10mm from the anterior and inferior margins. There is a segment of bone at the inferomedial aspect 35x15x12mm with no macroscopic evidence of tumour involvement.
Sections of parotid gland show a salivary duct carcinoma with evidence of intermixed pleomorphic adenoma (carcinoma ex pleomorphic adenoma). Invasive carcinoma is well-circumscribed with a pushing border. The tumour cells demonstrate a squamoid appearance with abundant cytoplasm and form large dilated ducts containing central comedonecrosis. Areas of chondromyxoid stroma with loosely arranged spindled and epithlioid cells represent the residual pleomorphic adenoma component.
Immunohistochemical results show tumour cells stain Her-2+, Androgen Receptor+, GCDFP+ and PSA-.
Completely excised salivary duct carcinoma arising from a pleomorphic adenoma (Carcinoma ex-pleomorphic adenoma), size 33mm with no bony, lymphovascular or perineural invasion. Negative lymph nodes.