- reversible intracellular accumulation of fat

- excess fat in the cell does not product injury and is reversible

- liver, heart, muscle, kidney

- hypoxia, hypoglycemia, alcohol, nutritional deficiency

- Oil Red O and Sudan black/red used to stain

Fatty Degeneration

- ingrowth of adipose tissue

- most commonly the right ventricle of the heart

- usually associated with obesity

Fatty infiltration

- liped laden macrophages seen in cerebral infarctions

Gitter cells

- result in clusters of cholesterol-filled macrophages called called cholesterolosis, xanthomas, xanthelasmas

Acquired and hereditary hyperlipidemia

- golden-brown iron-storage molecule

- stains blue with "prussian blue" stain

- occurs normally, especially in the bone marrow to make hemoglobin

- occurs abnormally in situations of iron overload systemic or local (old hemorrhage, multiple transfusions, genetic dx)

- ferritin is iron storage molecule

Hemosiderin

- moderate increase in iron storage from too much intake

- mostly in macrophages with little or no functional changes

Hemosiderosis

- massive increase in iron storage

- begins in parenchymal cells with macrophages later

- may produce dysfunction of parenchymal cells

Hemochromatosis

- endogenous golden-brown pigment

- seen in long-term stress or atrophy ("wear & tear" pigment)

- free radical injury and lipid peroxidation = debris & junk

- results in indigestible residue of autophagic vacuoles

- usually does not interfere w/ cell function

Lipofuscin

- endogenous black-brown pigment

- derived from tyrosine in melanocytes

- produced in organelles called melanosomes

- protective of damage by UV light

- increased deposits w/ sun exposure, metabolic dx, tumors but don't interfere w/ normal function

Melanin

- exogenous black pigment

- acquired from dust inhaled from environment

- deposits called anthracosis

- usually does not interfere with cell function

Carbon

- endogenous yellow-green to brown pigment which is a breakdown product of catabolism of hemoglobin macrophages

Bilirubin

- generic term for anything that is pink and homogenous

- "glass-like"

- can be intracellular (Mallory body-intermediate filaments or Russell bodies-immunoglobulins)

- OR extracellular (dense acellular collagen, corpora amylacea- PAS positive in prostate/lung/brain, DAD, ARDS, HMD, amyloid)

Hyalin

- fibrin exuded into alveoli is associated with this

diffuse alveolar damage (DAD)

- massive trauma causes release of cytokines and degranulation of neutrophils

Adult respiratory distress syndrome (ARDS)

- prematurity associated with lack of surfactant -> hypoxic damage to alveolar walls

Hyaline Membrane Dx (HMD)

- deposits in damaged or dead tissue, often as ECM

Dystrophic calcification

- deposits in living tissue due to disordered calcium metabolism

- blue-black crystals

Metastatic calcification