Tubular adenomas of the breast: a rare diagnosis

Imaging manifestations of ductal adenoma of the breast: A case report

Tubular adenomas of the breast are rare benign epithelium-derived tumours, and so few cases have been reported. Most often, the tumours are palpable, well-circumscribed masses in women of childbearing age and are commonly diagnosed as fibroadenomas both clinically and radiographically. We describe the case of a premenopausal patient with tubular adenoma of the breast who presented with small nipple discharge and a palpable breast mass. On imaging, tubular adenomas are practically indistinguishable from fibroadenomas and most commonly present as oval, circumscribed masses that are hypoechoic on ultrasound. On magnetic resonance imaging (MRI), tubular adenomas may present as lobulated or oval masses with a hyperintense signal on T2-weighted imaging and inhomogeneous internal enhancement on dynamic contrast-enhanced MRI. Pathologic findings after resection of the mass confirmed the diagnosis of tubular adenoma.

Tubular Adenoma of the Breast: Radiologic-Pathologic Correlation

Breast tubular adenomas (TAs) are rare, benign glandular epithelial tumors that arise from a proliferation of acini in the terminal duct lobular units. In the literature, 40 TA cases have previously been reported, and we describe 5 additional cases in this article. In the small number of reported cases, TAs present most often in women of reproductive age but may also occur in postmenopausal women. Mammographically and sonographically, TAs are almost indistinguishable from fibroadenomas (FAs), and they typically present on US as hypoechoic, oval, circumscribed, parallel masses with variable internal vascularity. TAs can also be seen on mammography as oval masses with microlobulated margins, or as grouped coarse, heterogeneous microcalcifications with or without associated mass or asymmetry. On MRI, TAs present as heterogeneously enhancing, T2-hyperintense oval masses with persistent kinetics. Histopathologically, TAs consist of closely packed round tubules with minimal stroma, in distinction to FAs, which have a prominent stromal component that surrounds and can distort the associated tubules. Because of their benign classification and excellent prognosis, patients with biopsy-confirmed TAs may resume routine screening. Complete surgical excision may be considered for cosmetic purposes or for TAs exhibiting associated suspicious calcifications or rapid growth.

Postmenopausal Tubular Adenoma of the Breast: A Case Report

Tubular adenoma (TA) of the breast is a rare, benign proliferative breast lesion that is predominantly composed of closely compacted tubules with an inner layer of epithelial cells and an outer layer of myoepithelial cells. They are regarded as residing on the opposite end of a spectrum of proliferative breast lesions from fibroadenomas, which are predominantly stromal. The majority of TAs are found in premenopausal women and the reason for this demographic predilection is not yet known. It is generally not possible to distinguish between TA and other, higher-risk breast lesions prior to biopsy or resection because the clinical and radiographic findings overlap. In this article, we present the case of a TA in a postmenopausal patient and review the epidemiology, histology, carcinogenic potential, and management of such lesions.

Ultrasound Findings of Breast Adenomas

OBJECTIVES

Breast adenomas are rare benign tumors. The aim of this study was to describe the ultrasound findings of breast adenomas, including less common worrisome features that can mimic malignancy.

METHODS

From November 2014 to November 2019, we performed 1605 core needle biopsies guided by ultrasound in our department. In all, 229 corresponded to fibroadenomas and 12 to breast adenomas.

RESULTS

Breast adenomas represented 0.75% of all core needle biopsies; 50% (6 of 12) were tubular adenomas; 17% (2 of 12) were ductal adenomas; and 33% (4 of 12) were lactating adenomas. Tubular and lactating adenomas occurred in young women and ductal adenomas in postmenopausal women. Lactating adenomas occurred in pregnant or breastfeeding women and were larger than the other adenomas. Ultrasound showed a mass with an oval shape, a parallel orientation, circumscribed margins, and hypoechoic and homogeneous patterns in most cases. However, up to one-third of them presented with suspicious findings.

CONCLUSIONS

Breast adenomas are rare benign entities with no specific clinical and radiologic features. Sometimes, they appear as suspicious tumors on radiologic modalities, requiring a histopathologic assessment to rule out malignancy. Radiologists need to be familiar with this entity to determine concordance between imaging and the final pathologic analysis.