Late Recurrence/Metastasis of Acinic Cell Carcinoma After 10 Years of Resection: A Case Series and Literature Review

Background: Acinic cell carcinoma (AciCC) is a relatively rare malignancy of the salivary glands, predominantly affecting the parotid gland. Recent studies report that the local recurrence rate for AciCC ranges from 5% to 17%, while metastasis occurs in 2% to 12% of cases. Most recurrences or metastases are observed within the first 5 years following initial therapy. However, late recurrences or metastases occurring more than 10 years have been reported in rare cases. Methods: This study presents 13 cases of AciCC in which patients experienced recurrence or metastasis 10 to 45 years after initial treatment. The case series includes 6 patients identified from our database and 7 cases from a literature review. Results: In this small series, late recurrence or metastasis appeared more common in female patients. Four patients experienced recurrence confined to the tumor bed, with or without regional lymph node involvement. Seven patients developed distant metastases, while 2 experienced both local and distant diseases. The lungs, bones, and skin were the most common sites of distant metastases. Management predominantly involved surgical resection of the recurrence, often followed by radiation therapy. Two patients also received chemotherapy for distant metastases. Follow-up data were available for 11 patients: 2 succumbed to the disease, 1 died of an unrelated condition, and 8 remained alive. Conclusions: Diagnosing late-onset recurrence or metastasis of AciCC poses a unique challenge, as the primary tumor may have occurred decades earlier. Further research is needed to deepen our understanding of the clinical course and adjust clinical follow-up strategy.