38. Neoplasia, nomenclature, definitions. Terminology (nomenclature) of neoplasms

Last updated on December 13, 2018 at 14:48

Definitions

When talking about cancer, it’s important to have our nomenclature in order.

A neoplasm is any abnormal mass of tissue that grows “outside” and uncoordinatedly with that of the normal tissue. The word literally means “new growth” in Greek. All cancers are neoplasms. Neoplasms don’t increase in size due to their local environment; they’re autonomic. They don’t care.

The word tumor was originally used for any swelling, however nowadays it’s used to indicate any neoplastic mass. Tumors can be benign, precancerous or malignant. Not all neoplasms are tumors, however all tumors are neoplasms.

Cancer is the term we use for a malignant (evil) tumor. Strictly not all cancers are tumors; leukaemia for example is a cancer but not a tumor. The word malignant indicates that the tumor can invade and destroy adjacent structures. Oncology is the study of neoplasms, especially cancers.

When we talk about the dignity of a tumor, we talk about how it behaves, or, in more precise terms, whether it’s benign or malignant. The following table illustrates the differences:

Benign Malignant
Most commonly innocent Destroy adjacent structures
Remain localized Invade adjacent structures
Does not spread (are never metastatic) Can spread to distant sites (can metastasize)
Easily removable with surgery Not easily removable with surgery

With modern medicine can even malignant tumors be treated or cured, especially if they’re caught in the early stages. Screening is therefore important.

Neoplasm terminology

Tumors have different names depending on whether they’re benign or malignant, and depending on which cell type they originate from. They’re best summed up in tables:

Tumors comprised of only one parenchymal cell type

Tumors of mesenchymal origin

Connective tissue and derivatives:

Tissue of origin Benign variation Malignant variation
Fibrous connective tissue Fibroma Fibrosarcoma
Adipose tissue Lipoma Liposarcoma
Cartilage Chondroma Chondrosarcoma
Bone Osteoma Osteogenic sarcoma

Endothelial and related tissues:

Tissue of origin Benign variation Malignant variation
Blood vessels Haemangioma Angiosarcoma
Lymph vessels Lymphangioma Lymphangiosarcoma
Synovium — none — Synovial sarcoma
Mesothelium — none — Mesothelioma
Brain coverings Meningioma Invasive meningioma

Blood cells and related cells:

Tissue of origin Benign variation Malignant variation
Haematopoietic cells — none — Leukaemias
Lymphoid tissue — none — Lymphomas

Muscle cells:

Tissue of origin Benign variation Malignant variation
Smooth muscle Leiomyoma Leiomyosarcoma
Striated muscle Rhabdomyoma Rhabdomyosarcoma
Tumors of epithelial origin
Tissue of origin Benign variation Malignant variation
Stratified squamous Squamous cell papilloma Squamous cell carcinoma
Basal cells of skin — none — Basal cell carcinoma
Epithelial lining of glands or ducts Adenoma Adenocarcinoma
Papilloma Papillary carcinoma
Cystadenoma Cystadenocarcinoma
Respiratory passages Bronchial adenoma Bronchogenic carcinoma
Renal epithelium Renal tubular adenoma Renal cell carcinoma
Liver cells Liver cell adenoma Hepatocellular carcinoma
Transitional epithelium (urinary tract) Transitional cell papilloma Transitional cell carcinoma
Placental epithelium Hydatidiform mole Choriocarcinoma
Testicular epithelium (germ cells) — none — Seminoma, embryonal carcinoma
Tumors of nervous system cells
Tissue of origin Benign variation Malignant variation
Melanocytes Nevus Malignant melanoma
Tumors originating from more than one cell type, but from the same germ layer
Tissue of origin Benign variation Malignant variation
Salivary glands Pleomorphic adenoma Malignant mixed tumor of salivary gland origin
Kidney precursors — none — Wilms tumor
Tumors originating from more than one cell type, and from different germ layers
Tissue of origin Benign variation Malignant variation
Totipotent cells in gonads or in embryonic rests Mature teratoma Immature teratoma
Dermoid cyst Teratocarcinoma

You can see from this that malignant mesenchymal tumors have the -sarcoma ending and malignant epithelial tumors have -carcinoma ending. Benign mesenchymal tumors have a simple -oma ending, while for benign epithelial tumors the naming is more complex but usually involves the -adenoma ending.

 


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