Hamartomas of the Breast: A Mimic of Fibroadenoma and Cytological Pitfall

The diagnosis and treatment of 56 cases of breast hamartoma: a single-center analysis and a review of the literature

Introduction

To analyze and summarize the clinical and pathological features of breast hamartoma to enhance clinicians' awareness of this rare and benign lesion of the breast.

Methods

We retrospectively described the clinical data, imaging results, and pathological findings of 56 patients with breast hamartoma who underwent surgical treatment at the First Hospital of Jilin University between January 2005 and December 2020, and summarized the features. Additionally, a literature review was conducted using the PubMed database for clinical reports on breast hamartoma and analyzed them.

Results

This study included 56 female patients. Preoperative ultrasound revealed round or elliptical heterogeneous echoes with clear boundaries: hypoechoic in 35 cases (63%), iso-echoic in 8 cases (14%), hyperechoic in 1 case (2%), mixed echo in 9 cases (16%), slightly strong echo in 1 case (2%), and uneven echo of fat in 2 cases (4%). Mammography was performed in 33 cases, revealing clear and dense shadows in 20 cases (61%) and dense shadows on the outer edges in 16 cases (48%). The excised masses were solid, with light yellow and gray cut surfaces. Pathological analysis identified ducts and fibrous tissue, with intra-tumoral fat content ranging from 10 to 90%.

Conclusion

Breast hamartoma is prevalent among perimenopausal women and is characterized by ultrasound and radiography; surgical intervention remains the primary treatment with a good prognosis.

Giant Myoid mammary hamartoma: A case report

ABSTRACT

Mammary hamartoma are rare neoplasms of the breast. Myoid mammary hamartoma are a subtype comprising of prominent smooth muscle component along with normal breast tissue components including fibrous, adipose, and glandular tissue. We report the case of a 38-year-old lady who presented with a large 21 × 15 cm, firm, mobile lump in right breast, clinically mimicking as phyllodes tumor. The lesion was reported as BIRADS 4a on mammography. Fine needle aspiration cytology suggested benign breast disease. Wide local excision was performed. The excised lump was solid, gray-white with fatty yellowish areas. Histological features were of myoid mammary hamartoma. To the best of our knowledge, this is the largest myoid hamartoma reported till date. Fine needle aspiration, needle biopsy, and immunohistochemistry are of limited value as diagnostic modalities in these lesions. Complete surgical excision, proper identification, and follow-up is essential, as these lesions, more commonly those which are incompletely excised, can recur.

Benign myofibroblastic/epithelial lesions of the breast with minimally infiltrative margins

A minority of mixed fibro-epithelial lesions of the breast lacks both fibroadenoma and phyllodes architectural patterns and have been previously labeled with different terms, including "hamartomas", "myoid/muscular hamartomas", "benign fibroadenomatous lesions" or "stromo-epithelial lesions of the breast". This study emphasizes the clinico-pathologic features of 5 cases of mammary benign fibro(stromo)-epithelial lesions sharing as a common morphologic theme the presence of minimally infiltrative margins due to the overgrowth of the stromal component into the surrounding fibro-fatty tissue. Notably the radiological features were suspicious for malignancy in 3 out of 5 cases. The following histologic features were seen in all cases: i) an epithelial component of benign glandular structures exhibiting the morphological spectrum of fibro-cystic disease; ii) a stromal component of bland-looking spindle cell myofibroblasts (vimentin + and α-smooth muscle actin +) set in a variably fibro-myxoid stroma. The present paper contributes to widen the morphological spectrum of the benign fibro-epithelial lesions of the breast, emphasizing the possibility that some cases, exhibiting a predominant myofibroblastic stromal component and minimally infiltrative margins, may be confused with other primary spindle cell mimickers of the breast. Accordingly, we propose the descriptive term "benign myofibroblastic/epithelial lesions of the breast with minimally infiltrative margins" for these previously underrecognized lesions.