Mucocele-like tumor of the breast caused by ductal carcinoma in situ: a case report

Mucocele-Like Lesions of the Breast: Rate of Upstaging and Cancer Development

BACKGROUND

Breast mucocele-like lesions (MLLs) are rare breast lesions. There is a paucity of literature on the rate of pathologic upstaging of MLL to in situ or invasive breast cancer. We sought to review our experience with MLL at a tertiary care center and review published literature.

METHODS

A retrospective review was undertaken of all patients with breast MLL at the Mayo Clinic, Rochester, from 1998 to 2016. Descriptive statistics were performed.

RESULTS

Overall, 30 patients were diagnosed with MLL, with a mean age of 54.6 years (range 51-58). Calcifications on screening mammogram were the most common method of MLL detection (n = 26, 86.7 %), with core needle biopsy (CNB) being performed in 29/30 patients. MLL with atypia was identified in 14 patients (48 %), and surgical excision was performed in 26 patients. Disease was upstaged to invasive disease in one patient (3.8 %) who presented with a palpable mass. With a median duration of follow up of 3.5 years [interquartile range 1-7.1], two patients developed contralateral invasive breast cancer (both patients had a remote history of invasive breast cancer on that side), and one patient developed contralateral in situ disease. Review of the literature demonstrates a 2.9 % upgrade rate of MLL without atypia on excisional biopsy.

CONCLUSIONS

The upstage rate of MLL identified on CNB to invasive disease at surgical excision in this series was 3.8 %. In cases with MLL presenting as calcifications, no cases were upstaged in this series. Across the literature, upstage rates of MLL without atypia on CNB are low, indicating excisional biopsy may be avoided in these cases.

Mucocele-Like Lesions of the Breast: An Audit of 2 Years at BreastScreen Auckland (New Zealand)

It is recommended that mucocele-like lesions be excised to enable differentiation between benign lesions and carcinoma. In addition, ductal carcinoma in situ may be found in close association. A small series of 12 lesions audited at BreastScreen Auckland has shown six benign, one atypical, and five malignant lesions. Although this is a small series, a high rate of associated malignancy has been reported.

Nodular Mucinosis of the Breast: A Case Report With Pathologic, Ultrasonographic, and Clinical Findings and Review of the Literature

Nodular mucinosis is an extremely rare breast lesion. This benign mass usually presents clinically as a poorly circumscribed, subareolar, myxoid mass in young female patients. We report a case of this rare breast lesion and discuss its clinical, radiologic, and histopathologic features. A 21-year-old white woman presented with a mass in the left breast of 6 months' duration. She had never been pregnant or had any history of breast feeding, surgery, trauma, or use of exogenous hormones or a family history of breast cancer. Clinical breast examination demonstrated a 1 cm “rubbery” mass directly under and continuous with the left nipple. The skin that covered the mass had an edematous and irregular appearance without erythema or drainage from the nipple. Ultrasonography demonstrated a 1-cm, nonintraductal, circumscribed, homogeneous, isoechoic mass that was continuous or part of the base of the left nipple. The mass was smooth, with a thin echogenic rim. Doppler flow showed some vascularity. These findings suggested a benign breast lesion, including a fibroadenoma or nipple adenoma. Despite reassurance, the patient desired excision of the lesion. Gross examination revealed a nodular, rubbery-firm, ovoid, pink, polypoid mass that measured 1.5 × 0.9 × 0.8 cm. Microscopic examination showed a well-circumscribed tumor with a nodular appearance, which consisted of an accumulation of pink myxoid tissue and contained spindle cells with bland-appearing nuclei, no mitosis, and mild cellularity. The pink myxoid tissue was stained with Hale colloidal iron and Alcian blue. The Alcian blue stain was removed by pretreatment with hyaluronidase. The spindle cells stained with vimentin and smooth muscle actin; however, they did not express smooth muscle myosin or cytokeratin. This report presents and discusses the pathologic, ultrasonographic, and clinical findings of this rare entity.