Neoplasm Intro and Benign Growth

So What’s a Neoplasm?

Neoplasia: “new growth”

Neoplasms are neoplastic growth with the uncontrolled or disorderly proliferation of cells resulting in benign or malignant tumors.

In 2006, there were over 10 million new cases worldwide and 6 million deaths (in the US 500,000 deaths/year)

Oncology: the study of neoplasms, comes from the “onkos” (a bulging mass).

Tumors have 2 basic components: proliferating tumor cells and supporting stroma with connective tissue and vessels.

Neoplasms are classified into benign or malignant based on the biological behavior

Benign Neoplasms: Resembles original tissue, grows slowly, does NOT metastasize, often encapsulated, does NOT invade and destroy

Malignant Neoplasms: undifferentiated, uncontrolled growth, invasion of tissues around them, metastasis

Incidence vs. Mortality

Incidence: how many people get it

Mortality: how many people die from it

The environment plays an important role. There are usually no major differences when comparing men and women.

Benign Tumors (-omas)

Benign tumors use the suffix -omas but there are a few exceptions like sarcoma or lymphoma

Biological Behavior of benign neoplasms: slow growth, often encapsulated, no metastasis, non-destructive

Papilloma

Papillomas arise from surface epithelium (skin, mouth, gut, bladder), usually are “finger-like” projections, and have various causes (HPV (CONTAGIOUS), warts, viral infections)

Adenomas

Adenomas arise from glandular epithelium (colonic polyps, thyroid, liver)

Of Mesenchymal Origin

Muscle, connective tissue, fat (lipoma), bone, cartilage

Most Common Benign Tumor

Nevus: the most common benign tumor, a pigmented mole, the proliferation of melanocytes

Hemangiomas

Hemangiomas: begin tumors of the vascular epithelium (color tells depth)

Infantile Hemangiomas

Infantile Hemangiomas: most frequent (~4-5% of newborns), appear at 4-6 weeks, grow quickly, and then disappear.

Congenital Hemangiomas

Congenital Hemangiomas: less frequent, present at birth, may remain or shrink or go pale.

Cavernous Hemangiomas: are most often congenital

Cherry Angiomas

Cherry Angiomas: AKA senile angiomas, occur with age.

Stork Bites

Stork bites are NOT hemangiomas, they are harmless nevus simplex, dilated capillaries, and typically fade with time.

Hamartomas

Hamartomas: are “tumors” but NOT neoplasms, they are a disorganized overgrowth of different cells and tissues not normally found in an organ.

Hamartomas are NOT a neoplastic proliferation of 1 cell type.

These grow at the same rate as normal tissues.

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Occurs usually in the lungs (the most frequent location) and consists of fat, cartilage, and connective tissue. In the kidney or spleen, we see nodules with increased red pulp (blood vessels with a tendency and bleed).