Tubular carcinoma of the breast. Light micrograph (LM). Tubular carcinoma is an uncommon type of invasive breast cancer. These carcinomas are usually small and consist of tube-shaped structures (purple). Tubular carcinoma generally has an excellent prognosis. Invasive ductal carcinomas (IDCs) develop in the milk ducts and spread to other tissues. Surgery tends to be the first treatment for invasive ductal breast cancer. Magnification: x 150 when printed at 10 centimetres high.