Which of the following is not applicable in germ cell or sex cord-stromal tumors of the testis?

Grading is not applicable in germ cell or sex cord-stromal tumors of the testis. Unlike many other cancers, which are graded based on the degree of differentiation of the cancer cells, germ cell tumors are classified primarily through staging, which describes the extent of disease spread at the time of diagnosis.

Staging involves assessing how far the cancer has progressed, utilizing the TNM (Tumor, Node, Metastasis) system or other staging classifications that are specifically designed for these tumors. This is critical for planning treatment and evaluating prognosis.

Diagnosis of these tumors is crucial and typically involves imaging studies, blood tests for tumor markers, and histopathological evaluation of tissue samples. Surveillance is also a significant aspect of management, as it allows for monitoring of patients post-treatment for any recurrence or progression of the disease. Grading, however, does not provide relevant information for germ cell tumors, making it not applicable.