
==== Front
Radiol Case Rep
Radiol Case Rep
Radiology Case Reports
1930-0433
Elsevier

S1930-0433(24)00850-1
10.1016/j.radcr.2024.08.063
Case Report
Invasive lobular carcinoma of the male breast: A case report
Zebbakh Hajar MD drzebbakh93@gmail.com
a⁎
Sassi Samia MD b
Adjou Nada MD a
Omor Youssef PhD a
Latib Rachida PhD a
Lamalmi Najat PhD b
Amalik Sanae PhD a
a Department of Radiology, National Institute of Oncology, Rabat, Morocco
b Department of Pathology, Ibn Sina Teaching Hospital, Mohammed V University, Rabat, Morocco
⁎ Corresponding author. drzebbakh93@gmail.com
12 9 2024
12 2024
12 9 2024
19 12 57585761
20 6 2024
11 8 2024
12 8 2024
© 2024 The Authors. Published by Elsevier Inc. on behalf of University of Washington.
2024

https://creativecommons.org/licenses/by-nc-nd/4.0/ This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
Invasive lobular carcinoma (ILC) is a rare type of male breast cancer, representing about 1% of cases. It often presents with a palpable mass and sometimes nipple changes, but is usually diagnosed late. ILC is more likely to be estrogen and progesterone receptor-positive and usually HER-2 negative. Its diffuse growth pattern makes it difficult to detect with imaging. Treatment typically follows protocols for female breast cancer, including surgery, chemotherapy, and hormone therapy, with tamoxifen being commonly used. Further research is needed to better understand its pathogenesis and to develop more effective, tailored treatments.

Keywords

Male breast cancer
Lobular breast carcinoma
Breast ultrasound
Histology
E-cadherin
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pmcIntroduction

Male breast cancer is rare, accounting for just 1% of all breast cancers, dominated by infiltrating ductal carcinoma (74%-95%) [1]. Lobular carcinoma is extremely rare, accounting for 1% of all male breast malignancies, probably due to the absence of lobular development in the male mammary gland. Their rapid evolution and aggressive nature require early diagnosis and prompt treatment.

Case report

A 63-year-old man, father of 2, obese and hypertensive, was admitted for bilateral gynecomastia (Fig. 1) with a hard retroareolar mass discovered on self-palpation, with no inflammatory signs of the surrounding skin. Mammography and breast ultrasound revealed an oval, irregularly contoured retroareolar mass classified as BI-RADS 5 (Fig. 2). A CT scan confirmed the presence of the breast mass (Fig. 3). An ultrasound-guided biopsy of the mass was performed. Microscopic study revealed a grade II breast carcinoma. (Fig. 4), demonstrating a carcinomatous proliferation of cords, unicellular trabeculae and isolated cells, with a fibro-glandular stroma and no intraductal or intra-lobular component (A). Immunohistochemical evaluation showed a high percentage of estrogen (90%) and progesterone (80%) receptor malignant tumor cells with strong intensity (C and D). E-cadherin was negative (B).Fig. 1 Bilateral gynecomastia.

Fig 1

Fig. 2 Mammography (A) and ultrasound (B) of the left breast: Retroareolar mass, oval with irregular contours, classified as BIRADS 5.

Fig 2:

Fig. 3 Chest CT scan in axial section showing a retroareolar, oval mass with irregular contours and tissue density in the left breast (blue star).

Fig 3

Fig. 4 Histologic section of the lobular carcinoma specimen.

Photomicrographs of specimens stained with hematoxylin and eosin A (X40) showing carcinomatous proliferation made up of cords, unicellular trabeculae and isolated cells, with a fibro-glandular stroma. Immunohistochemistry showed coexpression of estrogen receptor antibodies C (X40) and progesterone receptor antibodies D (X40). Absence of tumor cell labeling with E-cadherin B (X40).

Fig 4

Discussion

Invasive lobular carcinoma (ILC) is an exceptionally rare histological type of male breast cancer, comprising just 1% of all male breast malignancies. Several risk factors have been identified, including gynecomastia, prolonged exposure to estrogen, radiation, and endocrine disorders. Gynecomastia, a condition present in the patient of this study, is among these risk factors [[2], [3], [4]]. Approximately 7.5% of men with breast cancer have Klinefelter's syndrome, which significantly increases the risk of breast cancer [5]. Additionally, feminization processes also elevate the risk [6]. However, in this case, Klinefelter's syndrome and hermaphroditism were excluded due to the absence of chromosomal abnormalities. While BRCA2 mutations are prevalent in both invasive ductal carcinoma and lobular carcinoma, CDH1 mutations are notably more common in lobular carcinoma [7]. Our patient had none of the mutations described above.

Lobular carcinoma in men typically presents similarly to invasive ductal carcinoma, often with a palpable mass and sometimes nipple changes, which can lead to delayed diagnosis due to low initial suspicion. Lymphadenopathy is observed in some cases, with literature indicating its presence in 6 out of 18 cases reviewed. Male breast cancer predominantly affects older men, around their sixth decade of life, with no preference for either breast side [8]. Lobular carcinoma has a unique tendency for gastric metastases and can mimic primary gastric cancer, likely due to the shared loss of e-cadherin expression. It also has a higher incidence of bilaterality and multicentricity compared to invasive ductal carcinoma [9].

The diffuse growth pattern of lobular breast carcinoma, resulting from poor cell-cell adhesion due to e-cadherin loss, often eludes clinical and imaging detection. Mammography is particularly challenged in identifying LBC in men, as its growth pattern and opacity resemble normal breast tissue [10]. On MRI, CBL usually presents in both men and women as a well-circumscribed focal mass with regional or segmental enhancement without mass, complicating its detection [11]. Fine needle aspiration biopsy also has a high false-negative rate, often misdiagnosing LBC as invasive ductal carcinoma due to its ill-defined cytological features [12].

Histopathologically, LBC cells are small, monomorphic, and lack cohesion, with round or notched ovoid nuclei, occasionally presenting as signet ring cells. These cells infiltrate the stroma in a single-file pattern, minimally disrupting the surrounding architecture. LBC is classified into type A (classic) and type B (vesicular nuclei), displaying various architectural patterns (alveolar, solid, trabecular) and cytological features (pleomorphic, apocrine, histiocytoid, signet ring), collectively termed “mixed nonclassic ILC” [13].

Invasive LBC often expresses estrogen and progesterone receptors more frequently than invasive ductal carcinoma (IDC), but usually lacks HER-2, p53, and EGFR expression. SEER database findings show that 64.8% of male LBCs are ER-positive, 41.6% are PR-positive, and only 2.3% express HER-2 [11]. Negative e-cadherin staining is a significant diagnostic criterion for LBC, though some debate its necessity [14].

Recent research highlights the importance of understanding the unique molecular pathways involved in ILC pathogenesis. Studies suggest that LBC's loss of e-cadherin function leads to activation of the PI3K/AKT pathway, contributing to tumor progression and resistance to certain therapies. This insight opens potential avenues for targeted therapy against specific molecules in this pathway, such as PI3K inhibitors, which could be more effective in treating LBC than traditional therapies [16].

Furthermore, emerging data suggests that ILC has a distinct tumor microenvironment compared to IDC, characterized by a higher infiltration of tumor-associated macrophages (TAMs) and regulatory T cells (Tregs), which might contribute to its immune evasion and metastatic potential. Immunotherapy approaches targeting these immune components could offer new treatment strategies for patients with ILC [17].

Due to the lack of specific guidelines for managing male breast cancer, treatment protocols for female breast cancer are often applied, including surgical, medical, and radiotherapeutic approaches. Surgery, typically involving mastectomy and possibly sentinel node or axillary dissection, is the primary treatment. Medical treatments include chemotherapy and hormone therapy, though preoperative chemotherapy response is generally poorer than for IDC [11,13]. A high percentage of male breast cancers (80-85%) are hormone receptor-positive, making adjuvant chemotherapy and tamoxifen beneficial, despite limited evidence. Letrozole has shown potential in improving disease-free survival compared to tamoxifen [13]. Although only 3%-5% of lobular carcinomas are HER-2 positive, trastuzumab therapy for 1 year is recommended for this group, showing outcomes similar to IDC [15].

Conclusion

The lobular subtype of breast cancer in men is a complex and challenging disease that requires extensive research to better understand its pathogenesis and molecular profile. Improved insights into these areas are crucial for developing more effective and personalized therapeutic options. Given its distinct characteristics and treatment responses, further studies should focus on identifying specific molecular markers and potential targeted therapies. This approach aims to enhance patient outcomes and provide more tailored treatment strategies for those affected by this rare subtype of breast cancer.

Patient consent

Informed consent for publication was obtained from patient.

Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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