The most reliable feature of malignant tumor-

Ans. is `b' i.e., Metastasis Both local invasion and metastasis are features of malignant tumors, but metatasis is consdired the most reliable. "Metastasis unequivocally marks a tumor as malignant because benign neoplasms do not metastatize". Robbin's 7th/e 279 "Next to development of metastasis, invasiveness is the most reliable feature that differentiates malignancy form benign tumor". Robbin's 7th/e 278 What is metastasis and what is local invasion ? Metastasis Metastasis is the spread and growth of malignant cells to produce secondry neoplasm at a site distant from and discontinous with the primary neoplasm. It is the most reliable feature of malignancy. o With few exceptions, all cancer metastatize. The major exceptions are glioma of CNS and basal cell carcinoma of skin, But both of these are locally invasive. Local invasion The malignant tumors progressively infiltrate and destroy the surrounding tissue and tumor cells move beyond the normal confins a process that is called local invasion. Due to local invasion, malignant tumors are poorly demarcated from the surrounding normal tissue and a well ? defined cleavage plane is lacking that makes their surgical resection difficult, and even if tumor appears well circumscribed, it is necessory to remove a considerable margin of apperently normal tissues adjacent to the neoplasm. ) After metastasis, it is the most reliable feature of malignancy.