Presentation
Right facial swelling.
Patient Data
Enhancing mass centered on the right deep lobe of parotid gland and bellies of right medial and lateral pterygoid muscles, wrapping posteriorly around the mandibular ramus to extend into the superficial parotid.
Anteriorly the mass extends to the mandible and to abut the right lateral pterygoid plate, but no involvement of the pterygopalatine fossa. Superiorly it extends to involve the right temporomandibular joint.
The patient proceeded to ultrasound guided core biopsy.
Histopathology
MICROSCOPIC DESCRIPTION: The core biopsy shows parotid parenchyma. There is invasive carcinoma, surrounded by fibrous stroma. The tumor forms trabeculae and nests. No glands are noted. The tumor cells are focally crushed. They have enlarged nuclei, conspicuous nucleoli and moderate amounts of pale eosinophilic cytoplasm. There is no obvious keratinization. No mucous cells are seen. There is no comedo-type necrosis. No evidence of lymphovascular or perineural invasion is identified. The tumor cells are CK7, BER-EP4, GCDFP-15 and androgen receptor positive. They are c-kit, DOG1, PSA, PSAP, p40 and p63 negative. The immunoprofile is consistent with salivary duct carcinoma.
DIAGNOSIS: Parotid core biopsy: Features consistent with salivary duct carcinoma.
Case Discussion
Salivary duct carcinomas are rare salivary gland tumors, accounting for 1-6% of malignant parotid gland tumors. It most commonly presents as a rapidly growing mass in elderly men, and is aggressive with extracranial facial nerve involvement, perineural spread and early metastatic disease.