Neoplastic cellular characteristics delineate abnormal, often malignant, cell proliferation. An examination of each option follows:
A. Proliferating cell mass: Accurate. Neoplastic cells characteristically aggregate into a mass due to excessive proliferation.
B. Accelerated cellular growth: Also accurate. Rapid, uncontrolled proliferation is a defining trait of neoplastic cells.
C. Infiltration and harm to adjacent tissues: Correct. Malignant neoplastic cells exhibit the capacity to invade surrounding tissues.
D. Confinement to the initial site: Inaccurate. Cells restricted to their primary location are classified as benign; malignant (cancerous) cells possess the ability to infiltrate and metastasize.
Therefore, options A, B, and C exclusively represent correct characteristics.