Efficacy of Anti-HER2 Targeted Therapies on Peritoneal Metastasis of Lobular Mammary Carcinoma: A Case Report

Invasive lobular carcinoma of the breast is the most common 'special' morphological subtype of breast cancer, comprising up to 15% of all cases.It is composed of non-cohesive cells individually dispersed or organized in a single-file linear pattern in a fibrous stroma.Tumours are generally of a good prognostic phenotype, being low histological grade and low mitotic index, hormone receptor positive and HER2, p53 and basal marker negative, and with a generally good response to endocrine therapy.Despite this, clinicians face countless challenges in the diagnosis and long-term management of patients, as they encounter a tumour that can be difficult to detect through screening, elicits a very invasive nature, a propensity for widespread metastatic colonisation and, consequently, in some studies a worse long-term poor outcome compared with invasive carcinoma of no special type.