adenosquamous breast carcinoma

Adenosquamous Breast Carcinoma: A Rare and Unique Form of Invasive Mammary Carcinoma

Adenosquamous breast carcinoma (ASC) is a rare and unique form of invasive mammary carcinoma that occurs less than 0.2% of all cases of breast cancer [10]. It is characterized by the presence of both glandular and squamous differentiation, which distinguishes it from other types of breast cancer.

Key Features:

• Glandular and Squamous Differentiation: ASC exhibits both glandular and squamous cell components, making it a distinct subtype of metaplastic breast carcinoma [11].
• Low Grade Subtype: ASC is considered a low-grade subtype of metaplastic breast carcinoma, which means it tends to grow and spread more slowly than other types of breast cancer [13].
• Rare Variant: ASC is a rare variant of metaplastic breast cancer, accounting for less than 1% of all cases of invasive breast malignancy [14].

Clinical Presentation:

• Palpable Lump: ASC typically presents as a palpable lump, often in women over the age of 50 [14].
• Incidental Presentation: In some cases, ASC may be incidentally discovered during imaging or surgical procedures for other reasons.

Diagnostic Challenge:

• Lack of Distinct Imaging Characteristics: ASC lacks distinct imaging characteristics, making it challenging to diagnose using mammography or ultrasound.
• Subtle Histological Characteristics: The histological features of ASC can be subtle and may overlap with those of other benign lesions, adding to the diagnostic challenge.

Prognosis and Management:

• Low Grade Behavior: Despite its rarity, ASC tends to have a low-grade behavior, which means it is less aggressive than other types of breast cancer.
• Population-Based Study: A population-based study has been conducted to summarize the clinicopathological characteristics, prognosis, and management of ASC [12].

Overall, adenosquamous breast carcinoma is a rare and unique form of invasive mammary carcinoma that requires careful consideration in diagnosis and management.

Common Signs and Symptoms

Adenosquamous breast carcinoma, a rare form of metaplastic breast cancer, can manifest in various ways. While some people may not experience any symptoms at all, others may notice the following signs:

• A lump under the breast: This is usually the first sign of breast cancer, including adenosquamous carcinoma (8).
• Changes to the skin on and around the breast: Redness, dimpling, puckering, or an unexplained rash can occur due to the tumor's growth (2).
• Fluid discharge from the nipple: In some cases, a clear or bloody fluid may leak from the nipple, which can be a symptom of adenosquamous carcinoma (2).

Other Possible Symptoms

While not as common, other symptoms that may be associated with adenosquamous breast carcinoma include:

• Changes in breast size or shape: The affected breast may become larger or smaller than the other one.
• Nipple inversion: The nipple may turn inward or become inverted due to the tumor's growth.

Importance of Early Detection

It is essential to note that some people with adenosquamous breast carcinoma may not experience any symptoms at all, making early detection crucial. Regular mammograms and self-examinations can help identify potential issues before they become more serious (8).

References:

• [2] Symptoms
• [8] Nov 14, 2023 — A lump under the breast, which you may or may not feel, is usually the first sign of breast cancer. When you get a mammogram, your doctor may ...
• [1] Aug 9, 2024 — Tubular carcinoma: Strong and diffuse ER positivity · Radial scar with squamous metaplasia: Heterogeneous, positive staining for ER.
• [2] Oct 18, 2022 — Symptoms · Changes to the skin on and around the breast, including redness, dimpling, puckering or unexplained rash · Fluid discharge from the ...

Diagnostic Tests for Adenosquamous Breast Carcinoma

Adenosquamous breast carcinoma (LGASC) is a rare variant of metaplastic breast cancer, and its diagnosis can be challenging due to the lack of distinct imaging characteristics. However, various diagnostic tests are used to evaluate suspected breast cancers, including:

• Imaging modalities: Mammography, breast ultrasound, and breast magnetic resonance imaging (MRI) are commonly used to evaluate suspected breast cancers [13].
• Vacuum-assisted breast biopsy (VABB): This is the first choice technique for breast tissue sampling due to its ability to remove a larger amount of tissue, making it easier to diagnose LGASC [6].
• Core needle biopsies: These may be used to rule out other malignant entities and can provide valuable information for diagnosis [5].
• Immunohistochemistry: This is helpful in distinguishing between LGASC and tubular carcinoma, as well as in identifying myoepithelial markers such as P63 and smooth muscle myosin (SMM) [8].

Staging Tests

After a diagnosis of adenosquamous breast carcinoma is made, additional tests are done to determine the stage of cancer. These include:

• Imaging tests: To evaluate if cancer cells have spread within the breast or to other parts of the body.
• Biopsy: To confirm the presence of cancer in lymph nodes under the arm or elsewhere.

Specialists Involved

A team of specialists, including breast health specialists, breast surgeons, and radiologists, work together to diagnose and treat adenosquamous breast carcinoma [12].

References:

[5] S Priyadarshini (2022) [6] by G Romanucci · 2021 · Cited by 11 [8] by G Lewis · 2023 · Cited by 9 [13] Diagnostic methods are those used for further evaluation after a potential breast cancer is suspected either by abnormal imaging or by physical findings.

The differential diagnosis of adenosquamous breast carcinoma (ASC) involves distinguishing it from other benign and malignant breast lesions that may share similar histological features.

Key Features to Consider

• Sclerosing adenosis: A benign condition characterized by a sclerotic (hardened) appearance, which can be confused with ASC.
• Microglandular adenosis: A rare benign lesion that can mimic the glandular component of ASC.
• Tubular carcinoma: A type of invasive breast cancer that can have a similar histological appearance to ASC.
• Fibrosclerosing lesions: Benign conditions characterized by fibrosis and sclerosis, which can be confused with ASC.

Distinguishing Features

• The presence of squamous nests is a helpful feature favoring ASC over tubular carcinoma [8].
• The absence of lobular configuration and the infiltrative pattern of growth in ASC are key features that distinguish it from fibrosclerosing lesions [10].
• Low-grade adenosquamous carcinoma (LGASC) tends to have an indolent clinical behavior, unlike other triple-negative breast carcinomas [12].

Other Considerations

• Squamous cell carcinoma is a higher-grade and more aggressive form of breast cancer that can be distinguished from ASC by its morphology and prognosis [11].
• Adenoid cystic carcinoma, secretory carcinoma, fibromatosis-like metaplastic carcinoma, and low-grade adenosquamous carcinoma are considered low-grade triple-negative breast cancers, but they have distinct histological features that differentiate them from ASC.

References

[3] Low-grade adenosquamous breast carcinoma (LGASC) is a rare variant of metaplastic breast cancer characterized by well-developed gland formation mixed with solid nests of squamous cells in a spindle cell background. [8] The presence of squamous nests is also a helpful feature favoring LGASC over the differential diagnosis of tubular carcinoma. [10] The differential diagnosis between LGASC and other breast diseases is only possible histologically. [11] Squamous cell carcinoma. Adenoid cystic carcinoma, secretory carcinoma, fibromatosis-like metaplastic carcinoma and low grade adenosquamous carcinoma are considered low grade triple negative breast cancers. [12] Aims: Due to its rarity and non-specific clinical and pathological features, low-grade adenosquamous carcinoma (LGASC) of the breast continues to pose diagnostic challenges.