Adenoid cystic carcinoma of submandibular gland metastatic to great toes: case report and literature review.

Adenoid cystic carcinoma (ACC) is a rare malignant tumor of the salivary glands, with higher frequency in the submandibular gland, a prolonged clinical course, and poor long-term survival. It tends to metastasize to lungs, bone, liver, brain, and rarely to skin. Comprehensive skin examination and appropriate follow-up is recommended, since cutaneous metastasis represents disease progression, requiring management and prognosis adjustment.