microglandular adenosis

Microglandular Adenosis: A Rare Benign Breast Lesion

Microglandular adenosis (MGA) is a rare and benign proliferative lesion of the breast, characterized by an infiltrative growth pattern of small glands. It is often detected incidentally and occasionally presents as a palpable breast mass.

Key Features:

• Infiltrative pattern: The glands are haphazardly distributed in a hypocellular or fibrous matrix with extension into fatty stroma.
• Small uniform glands: Composed of small, round tubules with a single layer of uniform cuboidal or flattened cells and regular nuclei.
• Lack of myoepithelial layer: Unlike typical benign breast lesions or in situ lesions, the glands lack a myoepithelial layer.
• Thick basement membrane: A thick basement membrane is present around the epithelium.

Clinical Significance:

• Benign lesion: MGA is considered a benign lesion, but it can mimic invasive carcinoma due to its infiltrative pattern and lack of myoepithelial layer.
• Diagnostic pitfall: MGA can be easily mistaken for a low-grade invasive carcinoma, making accurate diagnosis crucial.

References:

• [1] Microglandular adenosis is a rare breast lesion that is often detected incidentally and occasionally presents as a mass (Fig. 1).
• [2] The glands are lined by a single layer of uniform cuboidal or flattened cells with regular nuclei and punctuate nucleoli.
• [3] A thick basement membrane is present around the epithelium, which can be observed under electron microscopy.
• [4] MGA is considered a benign lesion, but it can mimic invasive carcinoma due to its infiltrative pattern and lack of myoepithelial layer.

Common Signs and Symptoms of Microglandular Adenosis

Microglandular adenosis (MGA) is a rare benign breast condition that can mimic invasive tumors in its appearance. While it's not typically associated with severe symptoms, some individuals may experience the following signs and symptoms:

• Breast pain: A common symptom of MGA, which can be caused by the distorted lobules and scar-like tissue (1).
• Palpable breast mass: A benign lump in a single breast is often the first sign of MGA, typically affecting only one breast (11).
• Tender nodularities: Some individuals may experience tender nodules or lumps in their breasts, which can be painful to touch (15).

Other Possible Signs and Symptoms

While less common, some people with MGA may also experience:

• Breast lump: A palpable mass that can be felt during a self-examination or clinical examination.
• Changes in breast texture: The affected area may feel different from the surrounding tissue.

Important Notes

It's essential to note that microglandular adenosis is a benign condition, and most

Microglandular adenosis (MGA) can be challenging to diagnose, but various diagnostic tests and methods can help confirm the condition.

• Histopathological examination: MGA is often diagnosed by a pathologist through histopathological examination of tissue samples obtained from a biopsy. The characteristic small glands without a myoepithelial cell layer are a key feature of MGA [2].
• Immunohistochemistry: Immunohistochemical staining can help confirm the diagnosis of MGA, as it is typically positive for S100 and negative for other markers [2].
• Breast imaging: Imaging studies such as mammography, ultrasound, or magnetic resonance imaging (MRI) may show a heterogeneous segmental non-mass enhancement in the breast, which can be indicative of MGA [8].
• Core needle biopsy: A core needle biopsy can provide tissue samples for histopathological examination and immunohistochemical staining, helping to confirm the diagnosis of MGA [10].

It's worth noting that diagnostic problems may arise when differentiating MGA from carcinoma or assessing the extent of a carcinoma component [7]. Therefore, accurate diagnosis requires careful evaluation by a pathologist and possibly additional imaging studies.

References: [2] - Microglandular adenosis is devoid of a myoepithelial cell layer, and has a characteristic immunophenotype, being positive for S100 and negative ... [7] - Diagnostic problems include differentiating microglandular adenosis from carcinoma and assessing the extent of the carcinoma component. [8] - Breast magnetic resonance imaging showed a heterogeneous segmental non mass enhancement in the upper outer quadrant with less extension to lower outer quadrant. [10] - Ultrasonographic findings revealed a low echoic lesion with indistinct margins. The result of a core needle biopsy was MGA, which was confirmed ...

Based on the provided context, it appears that microglandular adenosis (MGA) is a rare breast lesion with uncertain malignant potential.

Treatment Options

While there are limited studies and information available on the treatment of MGA, here are some possible options:

• Surgical Excision: According to search result [13], surgical excision may be considered for MGA, especially if it's associated with invasive carcinoma.
• Observation: Search result [11] mentions that the follow-up time for patients with MGA ranged from 14 days to 8 years (mean, 4 y), suggesting that observation and monitoring might be a viable option for some cases.

Chemotherapy

There is limited information available on the use of chemotherapy in treating MGA. However, search result [12] mentions neoadjuvant chemotherapy in the context of triple-negative breast cancer, which may be relevant to some cases of MGA.

Immunotherapy

No specific information was found on the use of immunotherapy in treating MGA.

It's essential to note that the treatment approach for MGA may vary depending on individual circumstances and the presence of any associated conditions. A healthcare professional should be consulted for personalized advice.

References:

[11] - The follow-up time for patients with MGA ranged from 14 days to 8 years (mean, 4 y). [12] - Neoad

Differential Diagnosis of Microglandular Adenosis

Microglandular adenosis (MGA) is a rare benign lesion of the breast that can be challenging to distinguish from other proliferative and neoplastic lesions. The differential diagnosis of MGA includes:

• Well-differentiated invasive ductal carcinoma: This type of cancer can have a similar appearance to MGA, with infiltrative tubules and surrounding desmoplastic stroma.
• Sclerosing adenosis: Sclerosing adenosis is a benign lesion that can also present with microglandular architecture, making it difficult to distinguish from MGA.
• Acinic cell carcinoma: Acinic cell carcinoma is a rare type of breast cancer that can have a similar appearance to MGA, particularly in its microglandular variant.
• Low-grade invasive ductal carcinoma: Low-grade invasive ductal carcinoma can also be mistaken for MGA due to its bland-looking spindle cell morphology.

Key Features Separating Entities

To accurately diagnose MGA and distinguish it from these differential diagnoses, several key features should be considered:

• Immunohistochemical markers: The use of immunohistochemical markers such as estrogen receptor (ER), progesterone receptor (PR), and HER2 can help differentiate MGA from other lesions.
• Myoepithelial cell layer: The presence or absence of a myoepithelial cell layer can be an important feature in distinguishing MGA from well-differentiated invasive ductal carcinoma.
• Basement membrane: The presence of basement membrane, as confirmed by periodic acid-Schiff reaction, can also help differentiate MGA from sclerosing adenosis.

Clinical Implications

MGA is a rare variant of adenosis that can be easily mistaken for a low-grade invasive carcinoma. Accurate diagnosis and differentiation from other lesions are crucial to avoid unnecessary treatment and to provide appropriate management for patients with this condition.

References:

• [1] Joshi MG, Lee AK, Pedersen CA, et al. The role of immunocytochemical markers in the differential diagnosis of proliferative and neoplastic lesions of the breast. Mod Pathol 1995;8(3):257-265.
• [2] The most controversial differential diagnosis is between ACC with microglandular architecture and microglandular adenosis. Some authors consider the two entities as part of the same spectrum. The presence of intracytoplasmic granules, nuclear atypia and mitotic figures (even if rare) should favour the diagnosis of ACC.
• [3] Microglandular adenosis is a rare borderline neoplastic lesion of the breast composed of haphazardly located small, round tubules with a single. ... Thus, MGA should be strongly considered in the differential diagnosis of an ER/PR-negative lesion initially suspected to be a tubular, cribriform, or low-grade invasive ductal carcinoma.
• [4] Microglandular adenosis is a rare variant of adenosis characterized by the proliferation of small, round, and uniform ducts in a haphazard fashion. ... Here, a review of the features of MA together with the differential diagnosis with lesions showing microglandular structure is discussed. MA shows ...
• [5] MGA has a few different morphological variations, including microglandular adenosis (MGA), atypical microglandular adenosis (AMGA), and breast carcinoma-associated microglandular adenosis (BCMGA). ... leading to her diagnosis of AMGA. We provide a brief review of the pertinent literature, including diagnosis, differential diagnosis, molecular ...