Nipple Adenoma

Abstract

Nipple adenoma (NA) is a rare, benign proliferation of the nipple ducts. It may be clinically mistaken for Paget disease or squamous cell carcinoma; thus, microscopic evaluation is paramount. A large case series of NA has not been undertaken since the 1980s. Therefore, we undertook this study to evaluate the clinicopathologic characteristics of NA, emphasizing differential diagnoses and follow-up data. We retrieved 50 cases from our in-house archives or consultation files between 2003 and 2022. Available slides were reviewed, and clinical data and follow-up information were obtained. Cases must have exhibited a dense ductal proliferation in the breast tissue with proximity to the nipple epidermis. All patients were women; median age was 56 years. In all, 68% of patients were symptomatic; 53% demonstrated a skin growth. Overall, 67% were excised completely, either primarily (33%) or via re-excision after biopsy (33%). Four histologic patterns were noted: adenosis (dense proliferation of small-to-medium ducts); large duct (medium-to-large caliber ducts); papillary-like (frond-like architecture with branching, slit-like lumens); and pseudoinfiltrative (ducts squished and distorted by dense stromal fibrosis). Follow-up in 44 patients (88%) with a median time of 66 months showed no evidence of recurrence. NA demonstrates a wide spectrum of histopathologic variation. Subtyping of this entity is unlikely to be clinically relevant. Differentiation from invasive carcinoma or other histologic mimics (syringocystadenoma papilliferum, syringomatous adenoma) may be difficult. Simple excision is curative, and recurrence is rare. A definitive link to invasive carcinoma has not been established.

Nipple Adenoma: Systematic Review of Literature

“…We did not observe a preference in laterality between right and left nipples, contrary to some previous works. 2 NA and breast carcinoma, when concurrently observed, usually appear as independent lesions in distinct locations. Although a recognized association exists, the definitive link between NA and subsequent breast cancer development or a direct causal relationship for NA transforming into breast cancer has not been established but cannot be ruled out.…”

Nipple Lesions of the Breast

“…The exudate is often described as "nipple discharge," raising the differential diagnosis of an underlying intraductal papilloma or carcinoma. In a contemporary series 40 69% of patients with clinical information were symptomatic, and the most common symptom was bloody nipple discharge (24% of patients). In another series, 83% of patients 39 had nipple erosion and discharge.…”

“…Fewer than 10% of patients reported nipple pain or itching. 39,40 Thickening of the epidermis, erythema, and ulceration associated with a nipple adenoma may also suggest a benign cutaneous lesion such as eczema or psoriasis, or an infectious process, 41 prompting initial treatment with topical antibiotics and/or steroids without resolution of the lesion. Given these presenting symptoms, most nipple adenomas are detected when the tumor has a relatively small size and consists of a superficial palpable nodule.…”

“…By ultrasound examination, nipple adenoma may appear as a hypoechoic, irregular mass, an intraductal lesion or duct dilatation, abnormal texture of the nipple, or even as a nonspecific hypervascularity. 40 In most cases, a skin punch biopsy or a small incisional biopsy of the lesion is obtained for initial evaluation. If Paget disease is suspected clinically and only a shave biopsy of the eroded skin is obtained, the specimen may be too superficial and inadequate to diagnose nipple adenoma.…”

“…8A-E In a contemporary series, however, different morphologic patterns could not be easily subclassified, and more importantly, the different patterns had no clinical correlation. 40…”