How is a tumor classified in terms of its physical composition?

Tumors are primarily classified based on their physical composition, and a solid mass is a common characteristic of many tumors. This classification includes both benign tumors, which are non-cancerous and generally well-defined, and malignant tumors, which are cancerous and can invade nearby tissues. Solid tumors can arise from various tissues in the body and are characterized by the presence of a mass that can be detected through various imaging techniques or physical examination.

While liquid masses are associated with conditions such as cysts or fluid-filled tumors, they do not typically fall into the standard classification of tumors. Gases are not relevant in the context of tumorology, and fibrous tissue refers to a type of connective tissue rather than a classification of tumor mass. Therefore, identifying tumors as solid masses highlights their physical characteristics and aids in diagnosing and determining the appropriate treatment options.