Key Points

• Breast imaging for men is controversial due to the high prevalence of gynecomastia compared to male breast cancer.

• Most male breast lumps are diagnosed as gynecomastia, but other benign conditions include lipoma, epidermal inclusion cyst, breast hematoma, fat necrosis, and abscess.

• Malignancy was detected in only 1.65% of cases in the first cycle, and 0.8% of cases in the second cycle, with breast cancer in men being relatively rare.

• Gynecomastia is a benign condition that can affect between 32% and 66% of men in their lifetime.

• Comprehensive evaluation of male breast symptoms requires thorough history and examination to avoid unnecessary imaging and patient anxiety.

Introduction

In the last few years, the number of male patients who complain of breast lumps and discomfort has increased significantly (1). Recent epidemiological studies show that in the last 20 years the number of men who complain about breast discomfort has increased from 0.8% up to 2.4% (2). About 57% of men older than 44 years have a palpable breast (3).

The most frequent male breast condition is gynecomastia, a benign growth of glandular tissue, followed by lipomas and epidermal inclusion cysts (4). Men can also develop angiolipoma, schwannoma, and intraductal papillomas, which are benign breast diseases (5). In addition to these pathologies, several benign non-cancerous diseases can affect the male breast, including secondary syphilis, nodular fasciitis, hematoma, fat necrosis, subareolar abscess, venous malformation, intramammary lymph node, and diabetic mastopathy (6).

The use of breast imaging in male patients has become a topic for discussion due to the rising prevalence of male breast complaints (7, 8). Numerous studies have demonstrated that the majority of male breast problems can be diagnosed just by clinical examination (9). However, some scientists have argued that imaging may be required when the clinical diagnosis is ambiguous or the patient is at a high risk of breast cancer (3).

"Triple assessment", which combines clinical evaluation, imaging, and needle biopsy has been used for diagnostic evaluation in men with breast complaints (10).

The tests conducted in each situation depend on the patient’s age, clinical results, and symptoms (10). The first-line imaging technique for patients under 40 years old is ultrasound (US) (11). Patients between the ages of 35 and 39 who have clinically suspicious findings (P4 or P5) and/or ultrasonically suspicious findings (U4 or U5) should get a mammogram, ideally before getting a biopsy (3). When a palpable mass on mammography is hidden or only partially imaged, targeted US is necessary (11). US is reported to have higher sensitivity and specificity than mammography and is therefore the most sensitive for male breast cancer (11). For suspected or uncertain masses, a biopsy is required and is frequently attainable with US guidance (12).

Objective

This study sought to determine whether mammography or US should be included in the diagnostic workup of men with gynecomastia referred with a breast lump to the breast care center. The study also aimed to determine whether men referred because of a breast lump met the guidelines of the Royal College of Radiology (RCR), and the Association of Breast Surgery (ABS) (13, 14).

Standards

According to guidelines developed by the RCR and the ABS, mammography and/or ultrasonography are recommended in cases of unaccounted for or suspicious unilateral breast growth (P4 or 5) of the male breast. Imaging may be used in cases where there is clinical uncertainty (P3) regarding the difference between gynecomastia or fatty breast enlargement.

In males younger than 50 years, the preferred method of imaging is US, whereas bilateral mammography or US is recommended in those older than 50. Following imaging, needle core biopsy should be performed in cases where radiological findings are uncertain or suspicious (P3–5 and or R3–5), or when indeterminate clinical findings (P3) are not sufficiently explained by benign imaging findings (13, 14, 15).

Materials and Methods

A retrospective audit was conducted involving male patients who attended the two-week wait clinic in the Breast Care Unit at our institute between January 2019 and October 2019 (n = 303) for the first cycle, and between December 2021 and June 2022 (n = 117) for the second cycle.

The second audit cycle was conducted following the presentation and awareness of audit findings. The 'rolled-nipple’ technique, which is a well-known method, can be used to visualize subareolar ducts and was recommended for use in evaluation in suspected cases of gynaecomastia. Excluded cases included axillary lump, post-surgery surveillance cases, and paediatric cases. Depending on the age of the patient, radiological imaging was done either as mammography, or US. The P (Palpable) value grade given by a breast surgeon was recorded, as well as the M/U/R (Mammography/US/Radiological) values reported by radiologists. The pathological results of biopsies have also been recorded. The concordance between radiological and clinical diagnoses was assessed.

Results

In the first cycle (n = 303), the majority of cases (75.6%, n = 229) were diagnosed with gynaecomastia followed by lipoma 7.6% (n = 23), and normal breast tissue 7.6% (n = 23). The remaining cases were: abscess 1.0% (n = 3); sebaceous cyst 1.0% (n = 3); fat necrosis 0.3% (n = 1); lipoma with gynecomastia 1.0% (n = 3); lymph node 1.0% (n = 3); resolving bruise 0.3% (n = 1); pseudogynaecomastia 1.32% (n = 4); haematoma 0.6% (n = 2); oedematous breast 0.3% (n = 1); and cyst 0.6% (n = 2). Malignancy was detected in only 1.65% of cases (n = 5), of which two were incidentally detected on routine computed tomography (CT). Biopsy was performed in a total of eight patients (2.6%), which confirmed five cases of malignancy, four of which were invasive breast carcinomas, and one Hodgkin’s lymphoma. The other three biopsied patients were histologically proven as gynaecomastia.

The second cycle (n = 117), following presentation of the audit findings and recommended practice change, showed a decline in the proportion of gynaecomastia cases to 58.1% (n = 68) and a rise in lipoma cases to 15.4% (n = 18) compared to the first cycle. The remaining cases were: abscess 1.7% (n = 2); sebaceous cyst 2.6% (n = 3), epidermoid cyst 1.7% (n = 2), lymph node 0.85% (n = 1), pseudogynaecomastia 1.7% (n = 2), haematoma 3.4% (n = 4), oedematous breast 0.85% (n = 1), simple cyst 1.7% (n = 2) and normal breast tissue 11.1% (n = 13). Malignancy was detected in only 0.85% of cases (n = 1), which was proven to be papillary ductal carcinoma in situ (DCIS) with no invasive disease. Biopsy was performed in four cases (3.4%) and only one was proven to be malignant. The P grading for the malignant case was P5. Among the other three, two were histologically proven as epidermoid cyst and one gynaecomastia.

In the first cycle, four of the malignant cases were in the age group of 60–80 years and one between 40–50 years, the latter being a case of Hodgkin's lymphoma. The one malignant case in the second cycle was in the age group of >90 years.

We observed 100% concordance in both audit cycles between clinical diagnosis and imaging results when comparing the P grading given by clinicians for benign lesions as P2 and were concordantly found to be benign on imaging with R grading of R2. Thirty-seven (31.6%) patients were graded as P3 by the clinicians in the second cycle. Of these, only three were graded as R3 on imaging and underwent a biopsy, although none proved to be malignant and demonstrated results of benign findings. In contrast in the first cycle, ten (3%) patients were graded as P3 by the clinicians but only one was graded as R3 and underwent a biopsy which proved to be non-malignant (Table 1).

In the first cycle, 45% of patients had a mammogram, 32% had US only, and 23% had both imaging modalities. In the second cycle, 31% of patients had a mammogram, 33% had US only, and 36% had both imaging modalities. The p-value 0.0001 indicated that, significantly, despite the change in proportion of patients who is undergoing different imaging modalities, consistently similar results were observed in both the audit cycles as mentioned in Table 2.

Following the second cycle, there was a decline in P1/P2 referrals (-29.5%) and a steep rise in P3 grading referrals (+28.6%), increasing from 3% to 31.6%. However, only 8% of the P3 referrals were radiologically considered indeterminate/suspicious.  Further, the p-value of 0.001 suggested similar proportion to the first cycle as mentioned in Table 3.

Discussion and Conclusion

Seventy five percent of cases in the first cycle were diagnosed with gynaecomastia, followed by smaller proportions for lipoma and normal breast tissue. Malignancy was detected in only five of 303 cases, and among the five malignant cases, two were detected on prior CT as incidental findings. The second cycle showed a decline in the proportion of gynaecomastia cases and a rise in lipoma cases compared to the first cycle, although the gynaecomastia cases outnumbered the lipoma cases by almost 4:1. Malignancy was detected in only 0.85% of cases, which was proven to be papillary DCIS with no invasive disease. Results show that breast cancer in men is less common than in women (7, 16).

Breast cancer in men is relatively rare, affecting only around 1% and not being included in the top 20 cancers (16). Gynecomastia, on the other hand, is a condition that can affect up to two-thirds of men in their lifetime (17). It is therefore important to distinguish this group from other patients with lower malignant conditions (18). A soft, tender, mobile subareolar mass is the classic presentation of gynecomastia (Figure 1, 2, 3, 4) (19). A mass outside of the subareolar region is not considered to be gynecomastia (20). Moreover, gynecomastia does not increase the risk of developing male breast carcinoma (16). Patients with palpable breast tissues who are asymptomatic need only to undergo a thorough physical exam and a detailed history (8). For patients with symptoms of gynecomastia, laboratory blood tests may be performed to determine the underlying cause (21). It will reduce unnecessary anxiety among patients (7, 8). This will also improve the cost-effectiveness of the imaging department (7).

The prevalence of gynecomastia increases with age (21). Most patients presenting with breast symptoms were 51–70 years in the present study (22). The prevalence of gynecomastia is known to increase with age, and studies have shown that the majority of patients presenting with breast symptoms are between the ages of 51 to 70. A study conducted by Johnson and Murad (20) found a similar prevalence of 57% of gynecomastia in men over the age of 44. These findings indicate that the risk for developing gynecomastia is higher with age, and that healthcare professionals should be aware of that when evaluating males with breast symptoms (18). In addition, it has been reported that breast tissue may be palpable in 30% or more of the middle-aged adult male population, which increased to 60% or more by the seventh decade (23). In addition, the study found that gynecomastia is the leading cause of breast tissue enlargement in men older than 50 years (18). These findings emphasize the importance of taking patient age into account when evaluating males with breast symptoms (17).

Recent studies suggest that certain medications and medical conditions may also increase the risk for developing gynecomastia (20). Gynecomastia has been linked to obesity, liver disease and testicular tumours (17, 19). Some medications, including spironolactone and cimetidine, as well as some antipsychotics have been associated with the development of gynecomastia (24, 25). A comprehensive evaluation of males with breast symptoms should include a detailed medical history and physical examination that can determine the cause (26).

Lipoma, epidermal inclusion cyst, breast hematoma, fat necrosis, diabetic mastopathy, intramammary lymph nodes, and subareolar abscess are some of the other benign and rare conditions that may be encountered in the male breast (27). These conditions present with varying clinical characteristics, and a proper clinical history is necessary to establish the correct diagnosis (1). In our study these pathologies accounted cumulatively for 15.8% in the first cycle and 33.7% in the second cycle. Sebaceous cysts or epidermal inclusion cysts are benign intradermal lesions that present as a firm non-tender lump (Figure 5) (28). Lipomas are benign mesenchymal lesions made up of mature adipose tissues (Figure 6) (29). They typically appear as a soft, mobile and painless lump that can be palpated in the breast (30). This is the second most common cause for male breast lumps after gynaecomastia (29, 30). Our study found 7.5% in first cycle and 13.3% in second cycle. Pseudogynecomastia, which is caused by excessive fat deposits in the breast region, is rare (31). It is bilateral and has no palpable lump (31). Intramammary lymph nodes are typically found in the upper outer quadrant of the breast (Figure 7) (1). Breast hematomas can be mistaken for breast cancer if they are not interpreted correctly (30, 32). This includes hematomas that result from surgery, direct trauma, biopsy or contusion (Figure 8) (32). Fat necrosis in male breasts is rare and can be caused by a variety of factors, such as blunt trauma, prior breast surgery, radiotherapy or anticoagulant usage (33). Subareolar abscesses can present as a localized abscess or infection secondary to chronic obstruction and inflammation, and/or pain and swelling of the nipples (Figure 9) (34).

Our data showed that referrals for P1/P2 decreased during the second phase. This decline may be due to increased awareness of benign male disease by clinicians and radiologists after the presentation of the audit findings, as well as implementation of recommended change.

During the second phase, there was also a substantial rise in referrals for P3 grading, ten times higher in the second cycle compared to the first. However, the proportion of P3 referrals that were radiologically classified as indeterminate or suspicious remained relatively low at 8%, similar to the first cycle at 10%, where, p-value of 0.0001 which is less than the significant level of 0.005, indicated the similarity in both cycles It suggests that the increase in referrals for P3 was more due to over-caution by clinicians and an overuse than to a rise in suspicious cases.

The importance of radiological imaging in male breast assessment becomes apparent when considering the 37 patients who were referred as suspicious or indeterminate by clinicians in first cycle and 10 in second cycle (P3). Remarkably, only three of them were finally categorized as indeterminate following radiological imaging in the first cycle and only one in the second cycle (R3). This finding underscores the pivotal role that radiological imaging plays in evaluating patients falling within this ambiguous category. By offering objective and precise information, radiological imaging serves as a powerful tool in distinguishing between benign and malignant findings, ultimately facilitating well-informed management decisions and minimizing the need for unnecessary interventions.

The present study also showed that the concordance between clinical diagnosis (P1/2) and imaging results (R1/2) was 100% in both audit cycles for lesions thought to be benign by the clinicians. This suggests that the clinical examination was reliable and accurate in diagnosing benign breast diseases in men.

It is important to note that false positives and negatives can be a potential downside of the imaging methods used to diagnose breast disease in men (18). False positives may lead to an unnecessary biopsy or increased anxiety among patients (8). False negatives could result in a delayed diagnosis and treatment that leads to worse outcomes (7). It is important to weigh the pros and cons of male imaging to provide the best care for patients (7, 8).

In the last few years, there has been a notable increase in males presenting with breast complaints, with gynecomastia being the most prevalent condition. Other benign non-neoplastic entities can also affect the male breast. The role of imaging for male breast assessment is still a matter of debate. However, a clinical examination may be sufficient in most cases. Imaging may be used in cases where there is suspicion of malignancy, or if the physical examination results are inconclusive. Imaging is not recommended for gynecomastia, or lumps that have benign characteristics on clinical examination. Further research is required to elucidate the optimal role of imaging in male breast assessment. This will ensure that patients receive the best possible care.

Ethics Committee Approval: Not necessary.

Informed Consent: Retrospective study.

Peer-review: Externally peer-reviewed.

Authorship Contributions

Surgical and Medical Practices: C.F., A.S., J.K., M.K., Z.M.I.; Concept: S.B., Z.M.I.; Design: C.F., A.S., Z.M.I.; Data Collection or Processing: C.F., A.S., J.K., M.K., S.B.; Analysis or Interpretation: C.F., A.S., J.K., S.B., Z.M.I.; Literature Search: C.F., A.S., J.K., M.K.; Writing: C.F., A.S., J.K., M.K., Z.M.I.

Conflict of Interest: No conflict of interest was declared by the authors.

Financial Disclosure: The authors declare that this study received no financial disclosure.