Which grade of tumor shows no resemblance to the organ of origin?

Grade 4 tumors are characterized by a high degree of anaplasia, meaning that cancer cells have undergone significant changes and lack the structural and functional characteristics of the tissue from which they originated. This leads to tumors that show no resemblance to their organ of origin, indicating a more aggressive and poorly differentiated cancer, often associated with a worse prognosis.

In contrast, lower-grade tumors, such as Grade 1, typically retain some features of the original tissue, which can suggest a better differentiation and potentially a less aggressive behavior. Grades 2 and 3 demonstrate varying degrees of resemblance, with Grade 3 showing significant abnormalities but still possessing some characteristics of the original tissue. Therefore, Grade 4 stands distinct in its total lack of resemblance to the corresponding organ, highlighting its severe deviation from normal cellular architecture and function.