Salivary duct carcinoma presenting with unilateral multiple cranial nerve lesions and concurrent intracranial metastasis: A case report.

Abstract

Rationale: Salivary gland ductal carcinoma (SDC) is a rare malignant tumor of the head and neck, accounting for 1% to 3% of salivary gland malignancy. SDC usually occurs in parotid gland, has a high malignancy degree, poor prognosis, and is prone to distant metastasis. In particular, intracranial metastasis accompanied by multiple cranial nerve lesions is very rare, and early diagnosis is difficult, which easily leads to missed diagnosis and misdiagnosis. Therefore, the diagnosis and treatment of SDC face major challenges. We report a unique case of SDC, which initially presented with progressive facial paralysis followed by progressive intracranial metastases and multiple cranial nerve lesions. After surgery and pathological examination, SDC was finally diagnosed.

Patient concerns: A previously healthy 53-year-old male with persistent facial paralysis gradually developed symptoms of ipsilateral multiple cranial nerve lesions, and was hospitalized 8 months after onset.

Diagnoses: Brain magnetic resonance imaging enhancement showed multiple irregular intracranial T1 and T2 with uneven signal intensity. Brain computed tomography showed intracranial space-occupying lesions, the largest of which was about 55 × 42 × 38 mm, with extensive bone destruction. Pathological findings showed malignant cell mass in the left temporal lobe tumor. Immunohistochemical: (++), CK7(+++), AR(++), Brg-1(+), Her-2(2+), Ki67(+, approximately 80%), consistent with high-grade ductal carcinoma, considering salivary gland origin. The final diagnosis was SDC.

Interventions: The space-occupying lesions in the left cavernous sinus region and temporal lobe were partially resected. Local radiotherapy was recommended, but the patient refused.

Outcomes: Postoperative symptoms did not improve significantly. Follow-up after 4 months showed no improvement in the extensive cranial nerve lesions on the left side.

Lessons: In clinical practice, in the face of persistent facial palsy symptoms that gradually spread to other cranial nerves, the possibility of secondary facial nerve injury and malignant salivary gland tumors, especially SDC, cannot be easily ruled out even if imaging studies do not reveal any space-occupying intracranial lesions. Through the comprehensive use of imaging, pathology and immunohistochemistry and other diagnostic methods, the early detection and accurate diagnosis of SDC can be achieved, so as to provide the best treatment strategy for patients and improve the prognosis.