What is Lobular Carcinoma?
Lobular carcinoma is a type of breast cancer that originates in the
lobules, the milk-producing glands of the breast. This type of carcinoma is distinct from ductal carcinoma, which begins in the milk ducts. Lobular carcinoma can be classified into two main categories:
Lobular Carcinoma In Situ (LCIS) and Invasive Lobular Carcinoma (ILC).
Histological Characteristics
Under the microscope, lobular carcinoma exhibits unique histological features. In LCIS, cells are confined within the lobules and do not invade surrounding tissues. The cells appear small, uniform, and loosely cohesive due to the loss of the cell adhesion molecule
E-cadherin. In ILC, the cells invade the surrounding breast tissue in a single-file pattern, often forming a "Indian file" appearance. The lack of E-cadherin is also a hallmark in ILC, contributing to the discohesive nature of these cells.
Immunohistochemical Markers
Immunohistochemistry is crucial for diagnosing lobular carcinoma. The lack of E-cadherin expression is a key diagnostic marker. Other markers such as
cytokeratins,
estrogen receptor (ER), and
progesterone receptor (PR) are usually positive in lobular carcinoma. The expression of these receptors can guide treatment options, particularly hormone therapy.
Comparison with Ductal Carcinoma
Lobular carcinoma differs from ductal carcinoma in both histological and clinical aspects. While ductal carcinoma often forms glandular structures, lobular carcinoma cells tend to be more uniform and lack gland formation. Clinically, lobular carcinoma is more likely to be bilateral and multicentric compared to ductal carcinoma.
Diagnosis and Detection
Diagnosis of lobular carcinoma involves a combination of imaging techniques, such as mammography and ultrasound, and histological examination of biopsy samples. The lack of E-cadherin is often confirmed through immunohistochemical staining. Early detection is challenging due to the diffuse growth pattern of lobular carcinoma, which can make it less visible on mammograms compared to ductal carcinoma.
Treatment Options
Treatment for lobular carcinoma typically involves a combination of surgery, radiation therapy, and systemic treatments such as hormone therapy and chemotherapy. The choice of treatment depends on the stage of the cancer, hormone receptor status, and patient health.
Prognosis
The prognosis for lobular carcinoma is generally favorable, especially when detected early. The absence of E-cadherin and the presence of hormone receptors often indicate a better response to hormone therapy. However, the diffuse and multicentric nature of the tumor can sometimes complicate surgical options and increase the risk of recurrence.
Research and Future Directions
Ongoing research is focused on understanding the molecular mechanisms underlying lobular carcinoma, particularly the role of E-cadherin and other genetic mutations. Advances in targeted therapies and personalized medicine hold promise for improving outcomes for patients with lobular carcinoma.
