Histological Features
In histological terms, ILC is characterized by small, uniform cells that infiltrate the
stroma in a single-file pattern, which is often referred to as a "single-file" or "Indian file" arrangement. This infiltrative pattern is distinctive and helps differentiate ILC from other types of
carcinomas. The tumor cells often lack cohesion due to the loss of the cell adhesion molecule
E-cadherin, which is a hallmark feature of this type of carcinoma.
Diagnosis
Diagnosis of ILC typically involves a combination of
mammography,
ultrasound, and
biopsy. However, due to its diffuse growth pattern, ILC can sometimes be difficult to detect with imaging studies alone. Histological examination of biopsy samples is crucial for an accurate diagnosis. The presence of small, uniform, non-cohesive cells infiltrating the stroma in a single-file pattern is a key diagnostic criterion.
Immunohistochemical Staining
Immunohistochemical (IHC) staining is often used to confirm the diagnosis. The loss of E-cadherin expression is a significant finding in ILC. Additionally, IHC staining for
estrogen receptor (ER) and
progesterone receptor (PR) is typically positive in ILC, whereas
HER2/neu is usually negative. These markers not only help in diagnosing but also in determining the therapeutic approach.
Prognosis and Treatment
The prognosis for ILC is generally favorable, especially when detected early. The treatment plan may include
surgery,
radiation therapy,
hormonal therapy, and
chemotherapy. The choice of treatment depends on the stage and molecular characteristics of the tumor. Hormonal therapies are particularly effective due to the high prevalence of ER and PR positivity in ILC.
Challenges in Histology
One of the main challenges in histological analysis of ILC is its subtle and diffuse infiltration pattern, which can sometimes be missed in small biopsy samples. Additionally, the loss of E-cadherin is not always complete, which can complicate the interpretation. Therefore, a comprehensive approach combining histological examination and IHC staining is essential for accurate diagnosis.
Conclusion
Invasive Lobular Carcinoma is a distinct subtype of breast cancer with unique histological and molecular features. Accurate diagnosis relies heavily on histopathological examination and immunohistochemical staining. Understanding these features is crucial for effective treatment planning and improving patient outcomes.
