Salivary Duct Carcinoma with Invasive Micropapillary and Rhabdoid Feature Arising in the Submandibular Gland.

Salivary duct carcinoma (SDC) is a high-grade malignant salivary gland tumor associated with poor prognosis, frequent recurrence, and metastasis. An 82-year-old man presented at the department of oral and maxillofacial surgery at Tokai University Hospital with a painless swelling in the right submandibular region that had been there for 20 years. On presentation, an elastic hard tumor, 50 × 50 mm in size, was observed in the submandibular region. Diagnostic imaging was performed, and a malignant tumor in the submandibular gland was suspected. The suspected tumor was excised and postoperative radiotherapy and adjuvant-chemotherapy were performed. Despite this treatment, the patient died of multiple metastases 12 months postoperatively. SDCs are often diagnosed as carcinoma ex pleomorphic adenomas and multiple variants and subtypes exist. This case was histopathologically rare in terms of the coexistence of invasive micropapillary and rhabdoid features.