Neoplasia

By Dr. Eric Po Lasala, DPSP

Neoplasia

Ø Defined as a new growth

Tumor

Ø Its use in English language is equated with neoplasm

Oncology

Ø From the Greek word, oncos which means tumor

Ø The study of tumors and neoplasm

Cancer

Ø Latin word for crab

Ø Cancer, like a crab, adheres to any part that it seizes upon

Neoplasm as defined by Willis

Ø An abnormal mass of tissue, the growth of which exceeds and is uncoordinated with that of normal tissue and persists in the same excessive manner after the cessation of stimuli which evoked the change.

Ø The mass is purposeless, preys on the host and is virtually autonomous

Desmoplasia

Ø Formation of abundant collagenous stroma

Nomenclature

Ø 2 basic components of a tumor:

o Proliferating neoplastic cells that constitute the parenchyma

o Supportive stroma made of connective tissue and blood vessels

Benign Tumors

Ø Adenoma - benign epithelial cells that form glandular pattern or tumors that are derived from glands but do not form glandular pattern

Ø Papilloma - benign epithelial neoplasm forming microscopic or macroscopic finger like projections

Ø Cystadenoma - tumors with large cystic masses

Ø Papillary cystadenoma-papillary patterns that protrude into cystic spaces

Ø Polyp - benign or malignant tumor producing a visible projection above the mucosal surface

- Usually refer to benign tumors, when malignant they are called polypoid cancers

Ø Choristoma - ectopic rest of normal tissue

Ø Hamartoma - aberrant differentiation which may produce a mass of disorganized but mature specialized cells ingenious to the particular site, this is totally benign

Malignant Tumors

Ø Sarcoma - malignant tumors from messenchymal tissues, come from Greek word sar which mean fleshy because they have only little connective tissue stroma

Ø Carcinoma - malignant neoplasm of epithelial cell origin from any of the 3 germ layers

Ø Mixed tumors - a neoplasm with divergent differentiation of a single line of parenchymal cells

Ø Teratoma - a neoplasm made up of a variety of parenchymal cells types representative of more than one germ cell layer usually all 3.

Ø Melanoma- carcinomas from melanocytes, also called melanocarcinoma

Characteristics of a Neoplasm

Ø Differentiation

Ø Rate of Growth

Ø Local Invasion

Ø Metastasis

Differentiation

Ø Apply to the parenchymal cells

Ø It is the extent to which the parenchymal cells resemble comparable normal cells morphologically and functionally

Ø Well differentiated cells are composed of mature normal cells undifferentiated cells are anaplastic cells

Anaplasia

Ø Lack of differentiation

Ø Hallmark of malignant transformation

Ø Means “ to form backward”, that is implying reversion from a higher level to lower level of differentiation

Characteristics of Anaplasia

Ø Pleomorphism - variation in size and shape of the cell and its nuclei

Ø Hyperchromatic nuclei

Note from editor: This one ain’t complete. The powerpoint presentation, it seems, wasn’t completed by Dr. Lasala. So expect that this ain’t the only handout for neoplasia. ^_^ God bless in the test. 4 more months to go!