Breast tumours. Light micrograph of a section through a female breast, with non-cancerous (benign) tumours (neoplasms). The tumours are known as fibroadenomas, and occur in the milk producing tissues. They are found most often in women under 30. A fibroadenoma has a pericanalicular pattern, which consists of ducts surrounded by connective tissue (dark pink). The ducts are usually larger than in healthy tissue. Fibroadenomas can cause pain, distortion of the breast and flattened nipples. Treatment involves surgical removal and a pathological examination to rule out malignancy (cancer). Magnification unknown.