Medullary carcinoma may ask one among several different tumors of epithelial origin. As the term "medulla" may be a generic anatomic descriptor for the mid-layer of varied organ tissues, a medullary tumor usually arises from the "mid-layer tissues" of the relevant organ. Medullary carcinoma most commonly refers to Medullary thyroid cancer and Medullary carcinoma of the breast. Medullary carcinoma may also refer to tumors of the: Ampulla of Vater, Gallbladder, Kidney (Renal medullary carcinoma), Large intestine, Pancreas, and Stomach. Specialty. Oncology. Medullary carcinoma may ask one among several different tumors of epithelial origin. As the term "medulla" may be a generic anatomic descriptor for the mid-layer of varied organ tissues, a medullary tumor usually arises from the "mid-layer tissues" of the relevant organ.