What do colours indicate?
Tan - Many solid tumours are tan (beige to pale brown). This term is often used to describe the cut surface appearance of a solid tumour. This is one of our 'favourite' colours, particularly in very well fixed specimens! (In most specimens, you will be describing 50 shades of tan!)
Pale - An area of lighter colour on a slightly darker background e.g. areas of pallor superimposed on a tan tumour often indicate coagulative necrosis. Areas of infarction in solid organs are often pale - e.g. wedge-shaped pale infarct in the kidney. In a malignant tumour that grows rapidly and outstrips its blood supply, pale areas of necrosis may be seen within the tumour. (Go to the Practice! page to see an example in a kidney.)
Black
- Endogenous substances - e.g. blood - haemorrhagic areas are often dark brown to blackish. Melanin pigment is dark brown to blackish (hence a tumour mass that is blackish may represent a melanin-producing tumour, i.e. melanoma)
- Exogenous substances - carbon (e.g. in the lung, or in hilar lymph nodes), tattoo pigment
- Gangrene
(Go to the Practice! page to see an example in a lung.)
Green
- Processes involving bile accumulation, e.g. biliary cirrhosis, biliary obstruction, bile in the gallbladder
Yellowish green
- Purulent material, e.g. abscess fluid, fibrinopurulent serosal exudates in acute appendicitis
White
- Fibrosis, e.g. fibrous scar (may appear greyish white)
- Cartilage
- Fibrin, e.g. pale whitish areas in an arterial thrombus - lines of Zahn - whitish layers are platelets and fibrin
- Chalky whitish deposits - calcifications, e.g. pancreatic fat necrosis
Bright yellow
- Fat necrosis
