What's ductal adenocarcinoma composed of island of tumour cells with a marked peritumoural & instratumour lymphocytic infiltrate

My mom was diagnosed with a ductal adenocarcinoma composed of island of tumour cells with a marked peritumoural and instratumour lymphocytic infiltrate. Can you give me some brief info on this? We are seeing the doctor tomorrow but I just wanted to find some information on my own.

Thanks