Pathological Pigmentation By Dr. Hemn Hassan Othman PhD, Pathology, Fall 2018 10/20/2018 1
Pathological Pigmentation: Pigments: Pigments are colored substances accumulate abnormally within the tissue and organs, it can be: 1) Endogenous 1.Hemosiderin 2.Bilirubin 3.Lipofuscin 4.Melanin 2) Exogenous
1. Hemosiderin Local breakdown of red blood cells in tissues, e. g. in internal hemorrhage. The hemosiderin is a term refers to hemoglobin-derived, golden-yellow or golden-brown granules seen intracellularly.
Localized hemosiderosis results from local hemorrhage e.g.: a. The common bruise b. Pulmonary hemorrhage c. Cerebral hemorrhage Systemic hemosiderosis occurs in cases of: a. Increased absorption of iron. b. Impaired utilization of iron. c. Hemolytic anemia. d. Excessive blood transfusion.
common bruise
Pulmonary hemorrhage
Cerebral hemorrhage
Hemosiderin-laden macrophages in the lung
Organ: Liver Lesion: 1. Deposition of fine, golden-brown granules (black arrow) within the cytoplasm of hepatocytes (A). 2. The Prussian blue stain (specific for iron) shows bluish coloration of the deposited granules (B). Diagnosis: Hemosiderosis A B
2. Bilirubin The bilirubin is the major pigment of bile. It is derived from the hemoglobin but it contains no iron. Pathological accumulation of the bilirubin (bilirubinosis) within cells of all tissues and within body fluids is referred to as jaundice or icterus which is characterized by yellowing of the skin, mucous membranes and the sclera of the eyes.
Pathological accumulation of bilirubin occur in the liver as a result of obstruction to the bile flow (e.g., obstruction of the common bile duct by a stone), in this case liver will possess yellowish-green color grossly.
Yellow swollen liver with swollen gall bladder
Greenish swollen liver (Jaundice)
Organ: Liver Lesion: Yellowish deposits are apparent within the bile canaliculi, kupffer cells and hepatocytes. Lesion diagnosis: Bilirubinosis or cholestasis Etiology diagnosis: Bile duct obstruction due to gall stone
Organ: Liver Lesion: Yellowish deposits are apparent within the bile ducts, bile canaliculi, kupffer cells and hepatocytes. Lesion diagnosis: Bilirubinosis or cholestasis Etiology diagnosis: Bile duct obstruction due to gall stone
3. Lipofuscin This is a yellowish brown pigment having high lipid content, often found in the atrophied cells or in old age individual. It is particularly common in the heart muscle, and the term brown atrophy is often applied. It is also found in liver cells, testes and nerve cells as an ageing marks.
Lipofuscin in nerve cell
Lipofuscinosis due to ageing
Lipofuscinosis in the face
4. Melanin Melanin is a normal pigment found in the form of fine brown to dark granules in the skin, choroid and iris of the eye, hair follicles, meninges and adrenal medulla. An abnormal accumulation of melanin pigment in the skin or other tissues is referred to as melanosis or melanism, e.g.: a. Benin nevus (mole) of the skin. b. melanosis of the colon (melanosis coli). c. melanosis bulbi (melanosis oculi) of the eye.
Benin nevus
Benin nevus
Benign nevus should be differentiated from Melanoma which is a malignant tumor (cancer) originated from the melanocytes, it s one of the aggressive tumors which grow rapidly with ability of early metastasis.
Melanosis bulbi
Melanosis in face
Melanosis due to sun burn
Melanosis in the oral cavity
Complete absence of melanin pigment is called (albinism) which is a congenital defect in which the affected individual is called an albino, occur in human and animals.
Exogenous Pigments Coal dust particles It is the most common exogenous pigment. Pathological accumulation of carbon particles in the lungs is referred to as anthracosis miners diseases Pneumoconiosis which is characterized by blackish discoloration of lung tissue.
Anthracosis
Anthracosis in habitual smokers