[Adenoid cystic carcinoma of the breast, 22 years of experience]

Adenoid cystic carcinoma (ACC) is an uncommon neoplasm in the breast (less than 0.1%). ACC is typically triple negative with a favourable prognosis. Its low frequency and indolent course cause difficulties in the agreement of the evaluation and therapeutic consensus, as well as the use of the sentinel node excision in these carcinomas.

Our goal is to provide a new series of cases from the Complejo Hospitalario de Navarra, through retrospective review over a period of 22 years.

Every case of breast ACC diagnosed between 1998-2020 is reviewed. We analyze the clinical and pathological characteristics, and compare them with the literature.

We identified twelve cases of ACC, from a total of 18,241 patients diagnosed with breast carcinoma, with an average tumor size of 23.8mm and mean of 63.5 years. All of them were in a stage I-II at diagnosis. One case presented a lymph node micrometastases. One of them presented local recurrences and one case presented metastases 5 months after diagnosis (93.5 months of mean follow-up). According to Nottingham Histological Score, eight cases had a grade 1, two grade 2 and two grade 3. According to the classification of Ro et al., three were grade 1, four grade 2 and five grade 3. One case was ER positive (10%). No case presents positivity for BRAF-V600E in immunohistochemistry.

The management and prognosis ACC of breast, within benignity, remains uncertain, with more studies being needed to understand the clinical evolution and perform adequate therapeutic management.