A rare case of recurrent myoid hamartoma mimicking malignancy: imaging appearances

Myoid Hamartoma of the Breast With HMGA2 Rearrangement and Associated In-Situ and Invasive Carcinoma: Case Report and Review of Literature

Myoid hamartoma of the breast is an uncommon benign breast neoplasm. We describe an unusual example of an in-situ and invasive carcinoma arising in a myoid hamartoma. We also describe the unique molecular findings in the myoid hamartoma and review the pertinent literature. In radiology studies, the mammogram showed increased density/attenuation, and the ultrasound revealed a change in the overall echogenicity with hyperechoic and anechoic areas. The stromal compartment contained smooth muscle bundles and adipose tissue on microscopic examination. The stromal cells showed HMGA2 gene rearrangement by fluorescence in-situ hybridization analysis and overexpression of HMGA2 by immunohistochemistry. The breast myoid hamartoma is likely underpinned by HMGA2 gene rearrangement and HMGA2 protein overexpression, which can be used as an ancillary test to diagnose this rare breast lesion. Although most myoid hamartomas have a benign clinical course, the likelihood of malignant transformation should always be considered.

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.

Breast Hamartoma: Clinical, Radiological, and Histopathological Evaluation

Objective

Breast hamartomas are rare, benign, and slow-growing breast tumors that can be definitively diagnosed by combining the results of clinical, radiological, and histopathological examination. This study aimed to evaluate the clinical, radiological, and histopathological features of hamartomas and summarize our clinical approach to hamartomas.

Materials and Methods

Patients diagnosed with breast hamartoma between 2010 and 2020 in our clinic were retrospectively analyzed. Demographic information, clinical examination, radiological findings, histopathological features, changes during follow-up, and follow-up data were obtained and analyzed.

Results

Of the 1,429 patients operated on in our clinic for benign breast diseases between January 2010 and March 2020, 39 (2.7%) were diagnosed with breast hamartomas with histopathological examination. All patients were women with a median age of 37 (19-62) years. Most of the patients (64%) were in the premenopausal period. Radiological examinations were conducted using mammography (66%), breast ultrasonography (100%), and breast magnetic resonance imaging (48%). Biopsy was performed in 14 preoperative patients, and nine (64%) patients were diagnosed with hamartoma. All patients were operated on; 37 patients underwent a lumpectomy, and two had a mastectomy. No patients had hamartoma recurrence during an average follow-up period of 39 months.

Conclusion

Hamartomas are similar to other benign breast pathologies. Definitive diagnosis can be achieved by combining the results of clinical, radiological, and histopathological examination. Given its similar composition to normal breast tissue, hamartoma has a low rate of malignancy. Definitive diagnosis and appropriate surgical treatment are required.

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.

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.

Genetic Characterization of Myoid Hamartoma of the Breast

BACKGROUND/AIM

Myoid hamartoma of the breast is a very rare benign lesion of which only a few cases have been reported. The pathogenesis is unknown and nothing is known about its genetic constitution. We report here the genetic characterization of a myoid hamartoma of the breast.

MATERIALS AND METHODS

Cytogenetic, fluorescence in situ hybridization (FISH), RNA sequencing, reverse transcription polymerase chain reaction (RT-PCR), and Sanger sequencing analyses were performed on a myoid hamartoma of the breast.

RESULTS

G-Banding analysis of short-term cultured tumor cells yielded the karyotype 46,XX,t(5;12)(p13;q14)[6]/46,XX[4]. FISH showed rearrangement of the high mobility group AT-hook 2 (HMGA2) gene. RNA sequencing detected fusion of HMGA2 (12q14) with a sequence from 5p13. RT-PCR together with Sanger sequencing verified the HMGA2-fusion transcript.

CONCLUSION

Myoid hamartoma of the breast may be pathogenetically related to benign connective tissue tumors with HMGA2 rearrangements, such as pulmonary hamartomas, lipomas, myolipomas, and leiomyomas.

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.

Breast hamartoma: a clinicopathologic analysis of 27 cases and a literature review

OBJECTIVES

Breast hamartoma is an uncommon breast tumor that accounts for approximately 4.8% of all benign breast masses. The pathogenesis is still poorly understood and breast hamartoma is not a well-known disorder, so its diagnosis is underestimated by clinicians and pathologists. This study was designed to present our experience with breast hamartoma, along with a literature review.

METHOD

We reviewed the demographic data, pathologic analyses and imaging and results of patients diagnosed with breast hamartoma between December 2003 and September 2013.

RESULTS

In total, 27 cases of breast hamartoma operated in the Ankara University Medicine Faculty's Department of General Surgery were included in the study. All patients were female and the mean age was 41.8±10.8 years. The mean tumor size was 3.9±2.7 cm. Breast ultrasound was performed on all patients before surgery. The most common additional lesion was epithelial hyperplasia (22.2%). Furthermore, lobular carcinoma in situ was identified in one case and invasive ductal carcinoma was observed in another case. Immunohistochemical staining revealed myoid hamartoma in one case (3.7%).

CONCLUSION

Breast hamartomas are rare benign lesions that may be underdiagnosed because of the categorization of hamartomas as fibroadenomas by pathologists. Pathologic examinations can show variability from one case to another. Thus, the true incidence may be higher than the literature indicates.

Myoid hamartoma of the breast that proved difficult to diagnose: a case report

Myoid hamartomas of the breast are extremely rare breast lesions, with a poorly understood pathogenesis. We describe the case of a 38-year-old premenopausal woman who presenting with a mass in the left breast. Mammography revealed an oval mass that was partly indistinct, and ultrasonography showed a hypoechoic mass with a slightly irregular margin. Bilateral breast dynamic magnetic resonance imaging was performed for a more detailed evaluation. The images showed rapid initial enhancement and a microlobulated margin. Because the suspicion of malignancy was strong at that time, core needle biopsy was performed. Histologically, the tumor was identified as fibroadenoma. A case of myoid hamartoma of the breast that proved difficult to diagnose is reported, and discussed with reference to the literature.