Intermediate
Technical
IVT
capsular invasion
Tumor penetration through the fibrous capsule surrounding an organ, an important prognostic factor in thyroid cancer staging.
Full Definition
Capsular invasion refers to the histological finding of tumor cells extending through the fibrous capsule that normally contains thyroid tissue or encapsulated tumors. In thyroid pathology, this feature helps distinguish between encapsulated follicular adenomas and follicular carcinomas, with capsular invasion being a defining characteristic of malignancy. The extent of capsular invasion also influences T-stage classification and prognostic risk stratification in differentiated thyroid cancers.
Usage
Usage note: Distinguish from extrathyroidal extension, which refers to invasion beyond the thyroid gland itself.
In Context
- "Microscopic examination revealed focal capsular invasion, supporting the diagnosis of follicular carcinoma." — Histopathology report
- "The absence of capsular invasion in the encapsulated lesion favored a benign adenomatous process." — Pathology consultation
Also known as
capsule invasion
capsular penetration
Contrasted with
capsular integrity
Don't confuse with
vascular invasion
extrathyroidal extension