Positive surgical margins and durable disease control: A case of adenoid cystic carcinoma of the parotid gland treated with adjuvant radiotherapy

The parotid gland, the main site of adenoid cystic carcinoma (ACC) among the major salivary glands, represents a clinically significant location, particularly when the deep lobe is involved. This case illustrates the clinical and evolutionary heterogeneity of parotid adenoid cystic carcinoma. Despite the presence of positive surgical margins, adjuvant radiotherapy achieved durable locoregional control.

We report the case of a 45-year-old woman who presented with left-sided otalgia and headaches evolving over a two-year period. Magnetic Resonance Imaging (MRI) revealed a mass arising from the deep lobe of the left parotid gland. Total parotidectomy demonstrated adenoid cystic carcinoma with positive margins but without perineural invasion. Exclusive adjuvant radiotherapy was administered. After three years of clinical and radiological follow-up, the outcome remains favorable, with no evidence of local recurrence or distant metastasis.

We present the clinical, radiological, and therapeutic challenges raised by this adenoid cystic carcinoma of the deep lobe of the parotid gland, then analyze its underlying mechanisms and compare our observation with data from the literature.