Neoplasms are 

Neoplasms are newly produced cells formed through uncontrolled cell proliferation.

Neoplasms are abnormal mass of tissue that forms when cells grow and divide more than they should, meaning their division in uncontrolled. They may be malignant means cancerous or benign (non-cancerous). Cancerous ones may spread and invade nearby tissues. This is the major occurrence in cancer. For example, in case of lung cancer, the neoplasms begin at one location and with time spread throughout the lung tissue if not treated immediately.