Tubular Adenoma

TUBULAR ADENOMA Benign, usually round, nodules formed by a compact proliferation of tubular structures composed of the typical epithelial and myoepithelial cell layers. The epithelial cells are similar to those of the normal resting breast, but adenoma variants have been described where these show apocrine or lactating features. Tubular adenomas occur mainly in young females. They rarely occur before menarche or after menopause. They reportedly account for 0.13 to 1.7% of benign breast lesions Clinical features: The clinical and imaging features are usually those of fibroadenoma. Tubular adenoma usually presents as a painless, palpable, nodule, in some cases it has been evidenced during a screening program (screening mammography) (Soo). On mammography and ultrasound tubular adenoma presents as a nodule, varying in size, having well circumscribed borders Although tubular adenoma is usually noncalcified, on rare occasions microcalcifications have been described. Pre-operative fine needle aspiration cytological (FNAC) diagnosis may be of difficult interpretation. Needle core biopsy may help to reach a correct pre-operative diagnosis. Macroscopy: The tumors are firm, well circumscribed and homogeneous with a uniform yellowish, cut surface. Histopathology: The lesion is composed entirely of small round tubules with little intervening stroma. The latter may contain a few lymphocytes. The epithelial cells are uniform, with no atypia. Mitotic activity is usually low. The tubular lumen is small and usually empty, but eosinophilic proteinaceous material can be present. On rare occasion mucin secretion maybe abundant (Calderaro). Inspissated luminal mucin secretion can constitute the background of the microcalcifications (Soo) visible on radiological imaging. Occasional larger tubules give rise to thin branches. Combined tubular adenoma and fibroadenoma has been described. Rare cases have been described of in situ andor invasive carcinoma involving adenomas (tubular or lactating), a phenomenon also known to occur in fibroadenomas. Prognosis and predictive factors: in the 2003 WHO edition this section was unique for all types of adenoma. I suggest to maintain together tubular and lactating adenoma and to separate apocrine and ductal adenoma.