Salivary gland tumor: atypical presentation of breast cancer

ABSTRACT

Breast cancer is a heterogeneous disease with various histological and molecular subtypes. Among them, salivary gland tumors are rare and can be divided into three groups pure myoepithelial differentiation, pure epithelial differentiation and myoepithelial with mixed epithelial differentiation. In the last group, adenoid cystic carcinoma stands out, a rare entity with low malignant potential. It represents less than 0.1­3% of breast cancer cases and has the most frequent clinical presentation as a palpable mass. The diagnosis is confirmed by histology and immunohistochemistry. Classically, they are low-aggressive triple-negative tumors, with overall survival and specific cancer survival at five and ten years greater than 95%. However, there are rare reports of aggressive variants with a risk of distant metastasis and death. Treatment is based on surgical resection with margins. Lymphatic dissemination is rare, and there is no consensus regarding the indication of an axillary approach. Adjuvant radiotherapy is indicated in cases of conservative surgery and should be discussed in other cases. The benefit of chemotherapy remains uncertain, as most tumors are indolent. We report a case that required individualized decisions based on its peculiarities of presentation, diagnosed in an asymptomatic elderly patient during screening, in which mammography showed heterogeneous gross calcifications clustered covering 1.6 cm. Stereotacticguided vacuum-assisted biopsy was performed, and the area was marked with a clip. The anatomopathological examination led to a diagnosis of salivary gland-type carcinoma, triple-negative. The patient underwent segmental resection of the right breast and sentinel lymph node biopsy. The final anatomopathological result was similar to that of the biopsy, with an immunohistochemicalprofile of the adenoid cystic type and two sentinel lymph nodes free of neoplasia. Considering age and histological subtype, adjuvant therapy was not indicated. Follow-up for three years showed no evidence of disease