A solid tumour is an abnormal mass of tissue that usually does not contain cysts or liquid areas. Solid tumours may be benign (not cancer), or malignant (cancer). Solid tumour types are named according to the type of cell they originate from. Examples of solid tumours are sarcomas, carcinomas, and lymphomas. Leukaemias (cancers of the blood) generally do not form solid tumours.
The word tumor does not always imply cancer. In discussing tumors that are malignant (cancerous), however, the term solid tumor is used to distinguish between a localized mass of tissue and leukemia.
Relapsed refers to when a patient has received active treatment, went off treatment and then the disease came back, whereas refractory refers to disease that is progressing despite active treatment.