Melanoma : Tumor Infiltrating Lymphocytes
Tumor infiltrating lymphocytes (TIL) in melanoma convey important prognostic information. A dense lymphocytic infiltrate within and around melanoma appears to correlate with better prognosis.
The lymphocytic response is subdivided into three categories - brisk, non-brisk, or absent. BRISK: TILs are present throughout the vertical growth phase or across the entire base of the tumor. It is usually seen in thin melanomas. NON-BRISK: TILs focally infiltrate the tumor (as shown on the lower left corner of the image). ABSENT: TILs are absent altogether OR they are present but do not infiltrate the tumor. This type of response is generally seen in thick melanomas and correlates with the presence of sentinel lymph node metastasis.
The extent of lymphocytic response is directly linked with survival. For vertical growth phase tumors, the 10-yr survival rates for brisk, non-brisk, and absent TILs are 55%, 45%, and 27% respectively. However, it appears that the significance of these findings decreases when corrected for the tumor thickness.