Breast hamartoma: A report of 14 cases of an under-recognized and under-reported entity

Breast hamartomas associated with epithelial atypia and malignancy: are there specific clinical, radiological or pathological features that identify at risk patients?

PURPOSE

Breast hamartomas are rarely associated with epithelial atypia or malignancy. Since the introduction of digital mammography in the UK from 2008, hamartoma detection has increased. The aim of this study was to identify if there are characteristic clinical, radiological or histological features that distinguish hamartomas with intralesional atypia/malignancy (complex hamartomas, CH) or ipsilateral/contralateral atypia/malignancy (non-CH) from those without atypia/malignancy at diagnosis (other benign hamartomas, BH).

METHODS

We performed a retrospective single-institution review of 450 hamartomas reported between 2010 and 2023. Anonymised H&E sections and imaging of CH and non-CH were reviewed to identify distinguishing features.

RESULTS

13,441 benign breast lesions were biopsied/resected between 2010 and 2023 including 450 hamartomas (3.3%), 19 of which (4.2%) were associated with atypia or malignancy. 14 were analysed further (7 CH; 7 non-CH). The mean age of CH plus non-CH patients was significantly higher than patients with BH (47.5 vs. 40.6 years; p = 0.03). The mean size of CH was greater than non-CH (32.1 mm vs.17.6 mm; p = 0.06). There was a statistically significantly higher incidence of atypical/malignant lobular lesions (ALH/LCIS/ILC) in CH vs. non-CH (42.9% vs 0%; p = 0.05). MRI was performed in 2 CH and 3 non-CH; in all 5 the associated malignancy was detected. There was no significant difference between the CH and non-CH group in ultrasound/mammographic features, other hamartoma histological features or other associated benign breast changes.

CONCLUSIONS

Ultrasound/mammogram are not sufficiently sensitive to identify hamartomas with associated atypia/malignancy. Certain hamartoma features may preferentially be associated with atypia/malignancy and which merit further radiological and/or detailed histological investigation.

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.

A rare case of a breast hamartoma containing a lesion with malignant presentation on radiologic evaluation and benign presentation on pathologic findings: A case report

Mammary hamartomas are rare, benign, and often under-diagnosed breast lesions comprised of glandular, adipose, muscular, and fibrotic encapsulated components which occur more commonly among perimenopausal women. The term hamartoma was initially coined by Arrigoni in 1971 to describe breast lesions with clinical resemblance to fibroadenomas. The proper diagnosis of breast hamartoma is confirmed through using multiple radiologic and pathologic modalities. Hamartomas rarely progress into malignancy with only a few cases reported in the literature. Here, we report a case of a highly suspicious lesion developing within a breast hamartoma in a 46-year-old woman with radiologic features of a malignant lesion with benign pathology.

Breast Hamartoma With Synchronous Contralateral Breast Cancer: A Case Report

Breast hamartoma is a rare benign growth often overlooked and consequently not well-documented, mainly due to insufficient recognition of its distinct clinical and histological features. Increasing awareness about this relatively obscure benign condition is crucial because it can mimic both benign and malignant breast tumors clinically. Its association with breast cancer is infrequently documented in medical literature. Additionally, it may be linked to PTEN hamartoma tumor syndrome, which involves a mutation of the PTEN tumor suppressor gene. This article presents a case study of a young woman diagnosed with left breast carcinoma, where imaging revealed a sizable mass on the opposite breast consistent with a breast hamartoma.

Breast hamartoma: reassessment of an underrecognized breast lesion

AIMS

Breast hamartomas are an under-recognized lesion because they lack a distinctive microscopic appearance. Microscopic diagnosis can often conclude "no significant lesion" or "normal breast tissue", leading to repeated biopsies and diagnostic delay. We describe the histological, immunohistochemical and radiological features of breast hamartomas in the aim of identifying specific signs to facilitate their diagnosis and to differentiate them from normal breast and fibroepithelial lesions. METHODS AND RESULTS: Forty-seven breast hamartomas were reassessed (histological diagnosis and imaging features). An immunohistochemical study (ER, PR, CD34, HMGA2) was performed. On breast imaging, hamartomas most often presented as probably benign solid masses with circumscribed margins and variable densities. Histologically, breast hamartomas resembled normal breast, although their stromal component was predominant, separating randomly scattered epithelial elements, with areas of pure collagenous stroma. Pseudo angiomatous stromal hyperplasia (PASH) was present in 93.6% of cases and CD34 antibody highlighted intralobular, perilobular and interlobular distribution of CD34-positive fibroblasts. By comparison, CD34 was mostly expressed in the intralobular normal breast tissue stroma. Hamartoma stromal cells expressed HMGA2, ER and PR in 79%, 66% and 76.3% of our cases, respectively, compared to 7.7%, 23% and 19% in normal breast tissue, respectively (P<0.0001; P=0.0005; P<0.0001).

CONCLUSIONS

After ascertaining that core needle biopsy is effectively intralesional, breast hamartomas can be diagnosed with confidence by taking into account the presence of stromal changes, PASH, interlobular distribution of CD34-positive fibroblasts, HMGA2 and hormonal receptor stromal expression.

Recurrent myoid hamartoma of the breast mimicking malignancy

Myoid (muscular) hamartoma is a rare form of benign breast hamartoma composed of differentiated mammary glandular and stromal structures, fatty tissue and areas of smooth muscle from which its name originates. It is considered to be a variant of a mammary hamartoma. We report the clinical presentation, imaging appearances and treatment of the initial and recurrent presentation of this rare tumour in a 61year old female, which mimicked malignancy.  Although rare, myoid hamartoma's can reoccur and when they do they imaging appearances of benign and malignant tumours can overlap tend to mimic malignancy and histological diagnosis is mandatory.

Mammary hamartoma: is ultrasound-guided vacuum-assisted breast biopsy sufficient for its treatment?

Background

Mammary hamartomas were mostly benign tumors with rare rate of recurrence and malignant transformation. Ultrasound (US)-guided vacuum-assisted breast biopsy (VABB) has been reported sufficiently safe in treating many breast benign tumors but remained undefined in mammary hamartoma for its usual underdiagnosis in US. Thus, this study aims to evaluate the efficiency of US-guided VABB in treating mammary hamartomas.

Methods

From May 2015 to March 2019, 3,388 lesions of 2,534 patients underwent percutaneous US-guided VABB, among which 31 mammary hamartomas proved by pathology were included in this study. Patients were followed up by US three, six and twelve months later, then at 1-year intervals. Lesions were classified to analyze the possible factors associated with excision rate, bleeding volume and complications.

Results

Of the 31 patients, recurrence was seen in 1 case in 1 year after the procedure and complete excision rate was 96.8% (30/31). The bleeding volume ranged from 1 to 15 mL (mean number ± standard deviation, 6.5±3.4 mL) and significant statistical differences were detected in patient age and the largest diameter of lesions. The main complications included pain (22.6%), hematomas (9.7%) and ecchymosis (3.2%).

Conclusions

US-guided VABB ensures an outstanding complete excision rate and provides an alternative solution to treat mammary hamartomas.

A Male Patient With Breast Hamartoma: An Uncommon Finding

Mammary hamartoma is a rare type of breast tumor that is composed of the same elements as normal mammary tissue. This condition is very rare in men. In current literature, there are fewer than five case reports on male breast hamartoma. This benign pathology is under-reported because of several reasons. Since breast tumors are still considered an exclusively female diagnosis and statistically proven to be gynecomastia when arising in men, they are often overlooked. In addition to the uncommon clinical presentation in men, insufficiency of definitive pathologic and radiologic characteristics can make an accurate diagnosis a challenging task. Mammary hamartoma is a benign condition with an excellent prognosis. The following case describes a rare instance of an enlarging mammary hamartoma in a male patient, highlighting the imaging features, pathohistological findings, and clinical management.

Hamartoma of the breast in a man: A rare case report

RATIONALE

Mammary hamartoma is a rare benign breast tumor, composed of ducts, lobules, fibers, and adipose tissue. We describe a mammary hamartoma in a man; this is the fourth case being reported in the literature.

PATIENT CONCERNS

A 30-year-old man presented with a 1-month history of a painless mass in his right breast.

DIAGNOSIS

Ultrasound imaging and mammography revealed a lesion, approximately 2.0 cm × 2.0 cm in size, in the right breast, which was considered to be either a lipomyoma or an adenoma fibrosum.

INTERVENTIONS

The mass was surgically resected. Pathological examination confirmed the diagnosis of mammary hamartoma.

OUTCOMES

The patient was discharged from the hospital after surgery. There was no sign of reoccurrence during a 1-year follow-up period.

LESSONS

At present, mammary hamartoma is considered to be a benign lesion, usually treated by surgical resection. Some reports have suggested a possible association between a hamartoma and the development of breast malignancy. The pathology and biology of an association between a mammary hamartoma and malignancy have not been defined to date.

What you see is not always what you get: Radiographic-pathologic discordance among benign breast masses

The differential diagnosis for benign breast masses is broad and ranges from common lesions like fibroadenomas to rare masses like breast hamartomas. Fibroadenomas are proliferative benign masses made up of fibroglandular tissue. Hamartomas are neoplasms comprised of different tissues that are endogenous to the area where they originate. Breast hamartomas specifically, are rare, benign slow growing tumours comprised of fibrotic stroma, adipose, glandular tissue, and epithelial components. Both lesions are painless, firm, and are typically palpable on clinical exam. Given their similarities in composition, diagnosing these masses can be challenging, but may be confirmed with ultrasonography, mammogram, computed tomography, magnetic resonance imaging, or via histological specimen. Once diagnosed, surgical excision is the preferred treatment option. We present a 33-year-old woman with a large left breast mass that gradually increased in size and provide a review of the current literature regarding the challenge of distinguishing between breast fibroadenomas and hamartomas.

Mammary myoid hamartomas: reports of two cases and a review of the literature

The purpose of this report is to determine the clinicopathological and immuno-phenotypical characteristics of myoid hamartoma of the breast (MHB). The clinical data, histological morphology, and immunohistochemical results of 2 patients diagnosed with MHB were analyzed, and 15 cases of MHB reported in China were reviewed. Both patients were female, aged 28 and 35 years old, and their lesions were located in the upper outer quadrant of the left breast and the right breast respectively. The lesions measured 3 cm × 3 cm × 2.5 cm and 6.5 cm × 6 cm × 4.5 cm. A gross examination indicated a grayish solid block with clear boundaries. A microscopic examination showed different proportions of ducts and acini, beam myoid cells, adipose tissue, and fibrous stroma. The myoid cell bundles of both specimens were positive for vimentin, SMA, h-caldesmon and desmin, but negative for ER, PR, PCK, s-100, Calponin, and P63. Both cases were confirmed as MHB based on their clinical, histological and immuno-phenotypical characteristics. Our findings provide further insights into the pathological basis of MHB, which can help avoid both misdiagnosis and missed diagnosis.

Our 20-Year Institutional Experience with Surgical Approach for Breast Hamartomas

Objective

Hamartomas are rare, slowly-growing breast tumours. Clinical, radiological and histopathological examination together increase the diagnostic accuracy. To evaluate the clinicopathologic features of hamartomas and outline our clinical approach to hamartomas in our 20-year experience at our Breast Clinic.

Materials and Methods

Between 1995 and 2015, 24 cases were retrospectively analyzed with a diagnosis of breast hamartoma at our Breast Clinic followed by excisional biopsy. Data was obtained on patient demographics, clinical examination, radiological findings and histopathological subtypes.

Results

Of 1338 benign breast tumours excised from January 1995 to January 2015, 24 (1.8%) were identified as breast hamartoma. Median age of patients was 42 (range, 13-70), whereas the median tumour size was 5 cm (1-10 cm). On preoperative imaging, hamartoma was most commonly misdiagnosed as fibroadenoma. Pathological examination of the 24 biopsy specimens revealed 3 cases with pseudoangiomatous stromal hyperplasia, and another hamartoma associated with a radial scar within the centre of the lesion. Of those, one patient was diagnosed with malignant phylloides tumour in the same breast. At a median follow-up 58.4 months, none of the patients recurred or developed malignancy.

Conclusion

Hamartomas can often be missed by clinicians, due to its benign nature which is poorly understood. Despite their slow growth, hamartomas can reach large sizes and can cause breast asymmetry. Although it is rare, hamartoma can be seen along with malignancy, as it is formed from similar components of breast tissue. Therefore, careful diagnosis and appropriate management including surgery are required.

Juvenile Fibroadenoma at Menarche: A Case Series

Juvenile fibroadenomas of the breast are benign neoplasms. They present during the development phase of the breast. They are poorly understood because of their rarity and unpredictable behavior. In this article, a series of three different sonographic breast cases are provided of adolescent girls, who were brought for medical evaluation of a large breast lump, which had presented just after menarche. The results of evaluating these cases revealed that sonography of the breast was helpful in characterizing and delineating the extent of the lump. In conclusion, giant fibroadenomas of the breast, at menarche, are also known as juvenile fibroadenomas. They are a dilemma for the clinician, radiologist, and pathologist alike. The use of ultrasound can assist with characterizing these lesions, as an incorrect diagnosis could lead to a disfiguring surgery, for a young girl.

Expression of hormone receptors in low-grade adenosquamous carcinoma of the breast: A case report

RATIONALE

Low-grade adenosquamous carcinoma (LGASC) is a rare subtype of metaplastic breast carcinoma which is generally recognized as a characteristic subgroup of triple-negative breast cancers previously. However, in this study, we reported for the first time a case of LGASC with hormone receptors expression.

PATIENT CONCERNS

Pathological analysis of breast tumor specimen obtained by a 42-year-old female patient was performed. Morphologically, it composed of glandular structures with scattered squamous differentiation accompanied by haphazard arrangement of spindle cell stroma. Immunohistochemically, all myoepithelial and squamous differentiation markers showed typical LGASC positive or negative staining pattern. Interestingly, we found that normally aberrant hormone receptors were reactivated in this case. To our knowledge, this is the first report of a hormone receptor-positive LGASC. Apart from this, in the extended resection sample, we found scattered squamous metaplasia and florid adenosquamous proliferation (ASP). Meanwhile, it was positive for CD44 variant isoforms (CD44v), which is a breast cancer stem cell (CSC) marker, and expressed in LGASC, squamous metaplasia, and ASP.

DIAGNOSIS

LGASC with hormone receptors expression.

INTERVENTIONS

The breast-extended local excision and axillary lymph node dissection were performed.

OUTCOMES

The patient was free of local recurrence and distant metastasis 6 months after surgical resection.

LESSONS

We herein report the first case of LGASC with immunoreactivity for hormone receptors, expanding its profile of immunophenotypes. CD44v may play an important role in the transition of LGASC precursor lesions into malignant processes, which may serve as a therapeutic target in LGASC.