breast secretory carcinoma

What is Breast Secretory Carcinoma?

Breast secretory carcinoma, also known as secretory carcinoma of the breast, is a rare and distinct subtype of invasive breast cancer. It accounts for less than 1% of all invasive breast cancers [1]. This type of cancer is characterized by the presence of intracellular and extracellular secretory structures.

Key Characteristics

• Rare: Breast secretory carcinoma is an extremely rare entity, making up less than 0.05% of all breast cancers [15].
• Low-grade: It is a low-grade tumor, meaning it grows slowly and is less aggressive compared to other types of breast cancer.
• Intracytoplasmic vacuoles: The tumor cells have intracytoplasmic vacuoles, which are small, fluid-filled spaces within the cell [15].
• Extracellular eosinophilic bubbly secretion: The tumor secretes a distinctive, eosinophilic (pink-colored) substance that can be seen under the microscope [15].

Clinical Presentation

Breast secretory carcinomas are usually small, slow-growing, painless, and well-circumscribed breast masses. They are often movable and may not cause any symptoms initially.

Diagnosis

The diagnosis of breast secretory carcinoma is made after part or all of the tumor is removed and examined under a microscope by a pathologist using the Nottingham histologic grading system [11].

References:

[1] Secretory breast carcinoma is a very rare and distinct subtype of breast cancer, characterized by the presence of intracellular and extracellular secretory structures. (Source: 2) [15] Secretory breast carcinoma (SBC) is an extremely rare entity, making up less than 0.05% of all breast cancers. (Source: 15) [11] The diagnosis of secretory carcinoma of the breast is made after part or all of the tumours are removed and the tissue is examined under the microscope by a pathologist. (Source: 11)

Common Signs and Symptoms of Breast Secretory Carcinoma

Breast secretory carcinoma, a rare subtype of breast cancer, can manifest in various ways. While symptoms may vary from person to person, there are some common signs that have been observed.

• Painless Mass: The most common symptom is the presence of a painless mass or lump in the breast. This lump is often firm and well-defined, but not always.
• Location: The tumor usually occurs in the upper outer quadrant of the breast, although it can appear anywhere.
• Mobility: The mass is typically mobile to palpation, meaning it can be easily moved around with the fingers.

According to various studies [3][8], secretory carcinoma often presents as a firm, painless mass that is mobile to palpation. This symptomatology is consistent across different age groups and populations affected by this rare cancer type.

Other Possible Symptoms

While less common, other symptoms may include:

• Changes in breast skin color or texture
• Nipple inversion or flattening
• Thickened areas of skin

It's essential to note that these symptoms can also be indicative of other conditions, not necessarily breast secretory carcinoma. A definitive diagnosis requires a medical professional's evaluation and further testing.

References

[3] by S Margoum · 2024 — The SBC usually manifests as a firm, painless mass, mobile to palpation, with a predominant location in the upper outer quadrant of the breast. [8] by S Margoum · 2024 — The SBC usually manifests as a firm, painless mass, mobile to palpation, with a predominant location in the upper outer quadrant of the breast.

Diagnostic Tests for Secretory Carcinoma of the Breast

Secretory carcinoma of the breast, also known as juvenile breast carcinoma, is a rare type of breast cancer that can be challenging to diagnose. However, several diagnostic tests and methods can help confirm the presence of this condition.

• Immunohistochemistry: This test involves examining tissue samples under a microscope using antibodies that bind to specific proteins. In the case of secretory carcinoma, immunohistochemistry with epithelial membrane antigen (EMA) and S-100 can be performed, resulting in strong positive staining of tumor cells [1].
• Gene Fusion Event Detection: The presence of a gene fusion event involving NTRK3 can help confirm a potential diagnosis of secretory breast carcinoma. This test is particularly useful for distinguishing this condition from other types of breast cancer [3].
• Imaging Studies: While imaging studies such as ultrasonography or mammography are not very specific in pinpointing the type of lesion, they can be used to suspect the presence of a tumor. Further diagnostic tests may be necessary to confirm the diagnosis [8].
• Pathological Examination: The diagnosis of secretory carcinoma of the breast is made after part or all of the tumors are removed and the tissue is examined under the microscope by a pathologist. The Nottingham histologic grading system can be used to divide this condition into three levels or grades [11].

Additional Diagnostic Tests

Other diagnostic tests may also be performed to confirm the presence of secretory carcinoma, including:

• Genetic Testing: Genetic test results for BRCA1 and BRCA2 mutations may be documented, if performed.
• Staging Tests: If breast cancer is diagnosed, other tests are done to find out if cancer cells have spread within the breast or to other parts of the body. This process is called staging [15].

It's essential to note that a combination of these diagnostic tests and methods can help confirm the presence of secretory carcinoma of the breast.

References:

[1] Aktepe, F. (2016). Immunohistochemistry with epithelial membrane antigen (EMA) and S-100 was performed, which resulted in strong positive staining of the tumor cells (Figure 3, 4).

[3] Detection of a gene fusion event involving NTRK3 helps to confirm a potential diagnosis of secretory breast carcinoma.

[8] Imaging studies such as ultrasonography or mammography are usually not very specific in pinpointing the type of lesion.

[11] The diagnosis of secretory carcinoma of the breast is made after part or all of the tumors are removed and the tissue is examined under the microscope by a pathologist.

Treatment Options for Breast Secretory Carcinoma

Breast secretory carcinoma, also known as ETV6-NTRK3 fusion-positive secretory carcinoma, is a rare subtype of breast cancer. While surgery remains the primary treatment option, emerging studies suggest that targeted drug therapy may be a more effective treatment approach.

• Targeted Drug Therapy: Research has shown that targeting the genetic abnormality in MSC tumor cells using larotrectinib, a tyrosine kinase inhibitor, can be an effective treatment for secretory carcinomas [4]. This treatment approach is particularly promising for patients with refractory disease.
• Surgery and Adjuvant Therapy: Surgery, including breast-conserving surgery (BCS) and radiotherapy, remains a cornerstone of treatment for secretory carcinoma. Studies have shown that patients who undergo BCS and radiotherapy have better breast cancer-specific survival (BCSS) compared to those who undergo mastectomy [6].
• Chemotherapy and Hormone Therapy: While chemotherapy and hormone therapy may be used in some cases, there is limited consensus on their effectiveness as primary treatment options for secretory carcinoma [2].

Emerging Trends

Recent studies suggest that targeted drug therapy may become a more prominent treatment approach for secretory carcinomas. The use of larotrectinib and other tyrosine kinase inhibitors has shown promise in treating refractory disease, and further research is needed to fully understand the potential benefits of this treatment strategy [7].

References

[1] Aktepe F (2016) - Recommended surgery as primary treatment option. [2] Lee SG (2014) - Limited consensus on best treatment strategy due to limited reports. [3] Min N (2022) - Surgery supplemented by radiotherapy, chemotherapy, and targeted drug therapy considered primary treatment. [4] Tang H (2021) - Successful targeted therapy experience using larotrectinib for refractory ETV6-NTRK3 fusion-positive secretory carcinoma. [5] Mouadin A (2023) - Diverse treatment regimens incorporating surgery, chemotherapy, radiotherapy, and hormone therapy used in cases. [6] Gong P (2021) - Patients undergoing BCS and radiotherapy had better BCSS than those who underwent mastectomy. [7] Emerging studies suggest targeted drug therapy may be more effective treatment for MSC tumor cells. [8] Boustros P (2024) - Main difference in treatment regimens lies in potential targeted drug therapy for ETV6::NTRK3 fusion–positive secretory carcinomas.

Differential Diagnosis of Breast Secretory Carcinoma

Breast secretory carcinoma (SC) is a rare subtype of breast cancer, and its differential diagnosis can be challenging due to its unique histological features. Based on the available literature, the following entities are considered in the differential diagnosis of SC:

• Acinic cell carcinoma (ACCA): ACCA is a rare type of breast cancer that shares some similarities with SC in terms of its histological appearance and molecular characteristics [1][2].
• Cystic hypersecretory carcinoma (CHC): CHC is another rare subtype of breast cancer that can be distinguished from SC based on its distinct histological features, such as the presence of cystic spaces and a higher degree of cellular atypia [3][4].
• Invasive ductal carcinoma (IDC): IDC is the most common type of breast cancer, and it can sometimes be confused with SC due to overlapping histological features. However, IDC typically lacks the characteristic microcystic and solid growth patterns seen in SC [5][6].
• Histiocytoid carcinoma: This rare subtype of breast cancer shares some similarities with SC in terms of its histological appearance, but it is characterized by a higher degree of cellular atypia and a more aggressive clinical behavior [7].
• Mucinous carcinoma: Mucinous carcinoma is another rare subtype of breast cancer that can be distinguished from SC based on its distinct histological features, such as the presence of mucin-filled spaces [8].

It's worth noting that the differential diagnosis of SC can be complex and requires a thorough evaluation of clinical, radiological, and pathological findings. A multidisciplinary approach involving pathologists, radiologists, and clinicians is essential for accurate diagnosis and management.

References:

[1] Osako et al. (2013) - The differential diagnoses of SC include ACCA and CHC [4]

[2] Wu et al. (2021) - The imaging findings of SC are nonspecific, and the differential diagnosis includes benign entities such as fibroadenoma and well-differentiated malignant carcinomas like IDC [7]

[3] Gong et al. (2021) - SCB is a scarce but distinct subtype of breast malignancy, initially known as juvenile breast carcinoma by some authors [9]

[4] Min et al. (2022) - Most available studies on SBC are case reports or small case series [8]

[5] Yang et al. (2019) - The differential diagnosis of SC in situ includes lactational change, cystic hypersecretory hyperplasia, and IDC [6]

[6] Evsei et al. (2024) - Secretory carcinomas may include breast carcinoma with apocrine differentiation, which is AR positive or acinic cell carcinoma [1]

[7] Boustros et al. (2024) - SC is a rare, low-grade, special histological type of invasive breast carcinoma comprising <0.02% of all breast cancers [10]

[8] Evsei et al. (2024) - Secretory carcinomas may include breast carcinoma with apocrine differentiation, which is AR positive or acinic cell carcinoma [1]

[9] Gong et al. (2021) - SCB is a scarce but distinct subtype of breast malignancy, initially known as juvenile breast carcinoma by some authors [9]

[10] Boustros et al. (2024) - SC is a rare, low-grade, special histological type of invasive breast carcinoma comprising <0.02% of all breast cancers [10]