Background: Adenoid cystic carcinoma (ACC) is a rare neoplasm of the major salivary glands, characterized by a slow-growing tumor, wide local infiltration, perineural spread, a propensity to local recurrence and distant metastasis, and has a poor prognosis. Although surgery and radiotherapy are considered standard treatments, the role of systemic therapy in advanced and metastatic stages remains unclear and rarely results in complete remission. Due to the rarity and limited number of reported cases, here, we report a complete response with systemic treatment in a case of metastatic ACC of the salivary gland.
Case Presentation: The patient is a 50-year-old woman with a history of ACC of the submandibular salivary gland at 20 years old. No recurrence of the disease was observed until, at 47 years old, when metastatic adenocarcinoma with salivary gland origin was diagnosed. From the age of 47 to 50 years, multiple cervical lymph node involvement, multiple masses in the parotid gland and thyroid tissue, as well as distant metastasis to the breast, ovary, and lungs were observed. The patient underwent cervical lymphadenectomy, total parotidectomy, and several courses of radiotherapy and chemotherapy. After six cycles of the Bevacizumab + Adriamycin + Cisplatin regimen, radiologic evaluation confirmed a complete response to the treatment with the disappearance of pulmonary nodules and parotid lesions. The patient is currently under follow-up.
Conclusion: Our reported case shows the aggressive nature of recurrent metastatic ACC of the salivary gland and the positive effect and importance of systemic treatment in these patients. Because the metastasis can appear very slowly, early diagnosis is essential for a better prognosis. These rare malignant lesions should be followed up for a long time after initial treatment due to slow growth, frequent recurrence and late and distant metastasis possibility. This case highlights the potential of systemic therapy to induce complete response even in extensively metastatic disease, suggesting that further clinical trials may be warranted.
