Cancer, the Latin word for crab.

Although often attributed to Galen, it was the Greek physician Hippocrates, around 400 B.C., who first likened malignant tumors to a crab, noting specifically the appearance of a large breast tumor as seen just under the skin: swollen, subcutaneous veins (the crab's legs) radiating from a large, elevated, central mass (the crab's body). He called the affliction karkinos, Greek for crab, which was translated by the Romans into Latin, cancer.

Given the need for an abundant blood supply, a number of different cancerous tumors will take on this form, particularly in their advanced stages.

Cancer in a kidney. From Human Diseases by Ruth Tannehille-Jones and Marianne Neighbors; Published in 1999, Thomson Delmar Learning.