Diagnosis of some rare forms of breast cancer

Abstract

Background. Breast cancer (BC) is a heterogeneous disease, in which it is crucial not only to detect the tumor, but also to determine its biological characteristics to choose an optimal treatment strategy. Herein, we review existing literature on the subject and analyze own data.Aim. To analyze clinical and morphological characteristics of rare histological types of BC.Materials and methods. In this retrospective study, we analyzed the results of instrumental examination of 180 patients with mucinous BC treated in Sverdlovsk Regional Oncology Dispensary between 2020 and 2022. The mean age of the participants was 62.5 years. All patients underwent comprehensive examination, including digital mammography using the Fujifilm Amulet Innovality system, multiparametric ultrasound breast examination using the EPIQ 5 system (Phillips, Netherlands), and 1.5 T dynamic contrast-enhanced magnetic resonance imaging with a 16-channel – dedicated breast coil (GE Healthcare, USA).Results and conclusion. The incidence of mucinous BC was 1.8 %. Other rare types of BC, such as occult, medullary, papillary, tubular, and cribriform cancer were observed in less than 1 % of cases, which is consistent with the available literature data. Mucinous tumors were primarily represented by luminal B histology (73.3 %); the Ki-67 proliferation index was usually 35 %. The most common radiological manifestation was a hyperdense formation with clear contours (85 %). Ultrasound examination usually revealed a hypoechoic formation with clear and irregular contours (92 %); however, 8 % of patients presented with isoechoic formations that can hardly be distinguished from the background. Magnetic resonance imaging showed the following patterns: mass (87.5 %) with a persistent type of contrast accumulation (56.2 %) (type I curve) or curve exhibiting a plateau (43.8 %) (type II curve). Contrast agent accumulation started from the first minutes and was >100 % in all patients. Limitation of diffusion was observed in 25 % of patients. Patients with mucinous BC were usually characterized by late manifestation; 3 patients additionally had other cancers, including colorectal cancer, mucoepidermal tumor of the salivary gland, pancreatic cancer. None of these patients had family history of cancer. Isolated findings of X-ray mammography, ultrasound, and magnetic resonance imaging suggested benign breast tumors and no cancer-specific features.A multimodal approach enabled early detection of non-specific signs of rare forms of BC characterized by a specific clinical pattern with symptoms typical of this particular cancer from.