Overview of Disease Mechanisms in the Eye. Christopher M Reilly, DVM, MAS, DACVP Basic Science Course June 7 8, 2016 NC State University

Transcription

1 Overview of Disease Mechanisms in the Eye Christopher M Reilly, DVM, MAS, DACVP Basic Science Course June 7 8, 2016 NC State University *

2 Outline Tips on pathology submissions General processes and definitions Congenital/developmental Inflammatory Atrophic, dysplastic Neoplastic Stains (may not get to, but for your reference)

3 Submission Communication with your pathologist is key, regardless of who it is A little advanced planning can go a long way

4 Submission History, history, history SIGNALMENT SIGNS, clinical diagnosis/ddx DURATION Prior treatment LOCATION (if known, if applicable)

5 Submission If using big labs, ask ahead Some have eye interested and/or trained pathologists Your clinic may already have a preference If ancillary diagnostics expected (frozen section IHC, EM, PCR) plan ahead Prep client with flexible estimate Formalin is not always appropriate

6 Submission For best results: Remove adnexa/muscles MOST of the time, except Complex orbital margins Fornicial region is of interest Can submit adnexal tissues separately Indicate that they are to be examined Inking of complex margins can help

7 Developmental/Congenital/Genetic NOT synonymous e.g. goniodysgenesis, POAG, etc. Proper history can be essential e.g. Anterior chamber collapse v. anterior segment dysgenesis Dystrophies (e.g. corneal) Genetically determined, but late onset

8 Cellular Degeneration Injury can be lethal or sublethal Reversible or adaptive (sublethal) Not unique to the eye Occur in some unique patterns Ocular anatomy Physiology

9 Intracellular accumulations Intracellular edema Formerly hydropic degeneration Now acute cellular swelling or oncosis if severe e.g. corneal epithelium, osmotic cataract Typically reversible, unless severe

10 Corneal Epithelial Edema

11 Intracellular accumulation Other stuff Lipid (lipid corneal dystrophy) Also extracellular Hemosiderin (chronic/resolving hemorrhage) Lipofuscin (age, storage diseases, e.g. neuronal lipofuscinosis)

12 Hemosiderin Hematoidin

13 Extracellular Accumulations Edema Generally clear space Uvea, retina, orbital tissues, dermis/lids Cornea unique appearance of edema Overhydration of GAGs between collagen fibers = washed out appearance of expected artifactual corneal clefting When severe, fibers are wispy, irregular, and variably stained

14 Normal Canine Cornea

15 Corneal Edema

16 Mineralization Dystrophic Due to cell death, normal calcium Metastatic Hypercalcemia, normal tissue Mineral is basophilic in tissue section Often shatters/fragments with sectioning

17 Stromal/BM mineralization Band Keratopathy

18 Von Kossa Stain

19 Lethal Cellular Degeneration Necrobiosis Normal death of cells as part of development Keratinization, lens fiber senescence Typically unnoticed (i.e. normal)

20 Necrosis Cellular swelling oncosis Hypereosinophilia denatured protein Nuclear changes karyorrhexis Eventual loss of nuclear detail Secondary inflammation Tough call in single cells Overlap with apoptosis, etc

21 Necrosis retina Necrotic More viable

22 Necrosis cornea Can t occur to extracellular matrix (ECM) CAN occur in stromal tissue

23 Apoptosis Programmed cell death Can also be part of development Anterior segment, lymphoid development Intrinsic or extrinsic signals Classically: shrunken cells with uniform nuclear fragmentation/pyknosis No overt inflammation

24 Apoptotic keratinocytes

25 Tissue Degeneration Atrophy loss of tissue bulk Senile iris atrophy Optic nerve atrophy often with gliosis Phthisis bulbi widespread along with disorganization

26 Corpora Nigra

27 Atrophic Corpora Nigra

28 Optic nerve atrophy

29 Phthisis bulbi The end stage of severe ocular dz Must be differentiated from microphthalmia Criteria: Shrinkage Atrophy Disorganization

30 Phthisis bulbi

31 Phthisis, Cat

32 Phthisis bulbi, cat

33 Phthisis, cat

34 Inflammation Can affect any or all of the eye Classified by: Location Chronicity Cell type(s) Etiologies

35 Other Solar Elastosis Apoptotic squamous cell (sunburn cell)

36 Inflammation Includes both the fluid (edema, flare) and cellular (infiltrate, cell) events Corneal edema can be non inflammatory (endothelial disease) Fluid dysregulation, however, may lead to inflammatory changes Most eye diseases have some inflammatory or immune component

37 Types Neutrophilic Acute, innate Tissue destruction, necrosis keratomalacia Cavities/chambers Surfaces

38 Lymphocytic plasmacytic Chronic, adaptive At least a couple days Tissue response (e.g. uvea) Often perivascular, sometimes nodular Etiologically nonspecific Proportion can help (plasma cells in FIP)

39 Lymph/plasma cell/mott cell

40 Eosinophilic Acute or chronic Allergy, foreign body, parasites Immune/idiopathic Eosinophilic keratitis Grossly characteristic Granular on corneal surface Luna s stain can highlight

41 Luna s Stain, Eos

42 Granulomatous Variably strict definitions True granulomas Granulomatous inflammation sheets Plump, activated, interdigitated Histiocytic infiltrates Idiopathic/Immune mediated histiocytoses Common, confusing, poorly understood

43 Granulomatous Search for etiology Fungal stains: GMS, PAS, BCG IHC Mycobacterial Fite s, Ziehl Neelsen AF, BCG Foreign body polarized light for plants, plastic, suture, hairs, cotton Wrong diagnosis = wrong treatment Steroids v antimicrobials May need fresh tissue for culture Think before you fix

44 Granuloma

45 Fibrosis Common end result of inflammation Indicates chronicity Corneal fibrosis/scarring Uvea is resistant But chambers and surfaces prone Pre iridal, cyclitic, retrocorneal, vitreal, epiretinal Often associated with prominent vessels

46 Corneal Fibrosis

47 Dystrophy Inherited*, non inflammatory, bilateral lesions Corneal opacities in vet med Endothelial dystrophy Better characterized in humans Boston Terriers, Dachshunds, Chihuahuas Often secondary true dystrophy?

48 The plasias Aplasia complete failure to form Ocular agenesis Segmental: coloboma Hypoplasia failure to reach normal size Microophthalmia Optic nerve hypoplasia Hyperplasia non neoplastic proliferation of cells Corneal epithelial hyperplasia v hypertrophy increase in the size of individual cells RPE hypertrophy with detachment

49 The plasias Dysplasia abnormal development Retinal dysplasia Goniodysgenesis Metaplasia transdifferentiation to another cell type Osseous metaplasia Epithelial mesenchymal transition Squamous metaplasia of conjunctiva (vitamin A) Neoplasia unregulated growth of cells Benign or malignant

50 Neoplasia Round cell: leukocytes (melanoma?) Sheets No real pattern, architecture Epithelial polygonal, cuboidal, columnar Nests, cords, tubules, acini, islands Mesenchymal spindle cells, mostly More vague patterns, streams, whorls, etc

51 Aging Variably significant, can be subtle Nuclear sclerosis, senile cataract Thickening of DM and lens capsule Hyaline material in ciliary body Cystic degeneration of neuroepithelia Asteroid hyalosis

52 Asteroid Hyalosis, dog

53 Ciliary Hyalinization

54 Systemic Disease Metabolic Diabetes mellitus (cataract, uveitis) Hypertension (retinal hemorrhage, etc) Neoplasia Metastasis Infection FIP, systemic mycoses, West Nile Virus

55 Questions?

56 Common Special Stains I Periodic Acid Schiff Starch (glycogen, glycoproteins, fungi) Magenta Alcian Blue (Alb) Mucopolysaccharides, GAGs Bright blue i.e. vitreous Along with PAS Deep Blue Cartilage

57 Common Special Stains PAS-positive vascular deposits in diabetic vasculopathy Periodic Acid Schiff PAS Carbohydrates (BM, fungus, cellular debris, mucus, Lipofuscin) Magenta Often done w/ Alcian Blue Grocott s Methenamine Silver GMS Similar to PAS, can stain differently Black can be confusing in pigmented eyes Light green counterstain

58 Neurnal Ceroid Lipofuscinosis H&E

59 Neuronal Ceroid Lipofuscinosis PAS

60 Common Special Stains II Tissue Gram stain Typically Brown & Brenn (B&B) Gram +, Gram (often weak) Yellow background Other techniques better for some Brown and Hopps for Klebsiella spp.

61 B&B Tissue Gram Stain

62 Common Special Stains III Von Kossa Phosphate, black Prussian Blue (or Gomori s, Perl s) Iron (hemosiderin) Masson s Trichrome Muscle = red; Collagen = Blue; Cytoplasm = Pink; Nuclei = Blue/black

63 Von Kossa Stain

64 Optic nerve, Trichrome

65 Common Special Stains III Luna s Stain eosinophil granules Red/brown Giemsa/Toluidine blue metachromatic Mast cells (purple) Bacteria (pink)

66 Luna s Stain, Eos

67 Giemsa

68 Common Special Stains IV Fontana Masson Melanin Black in a VERY pale background Mucicarmine Mucus Pink, can highlight Cryptococcus Acid Fast (Ziehl Neelson, Fite s) Mycobacteria, other Acid Fast Red wblue background Fite s for atypical AFB (e.g. M. leprae)

69 Mucicarmine

70 Special Stains V Oil Red O, Sudan Black Lipid, can t be on processed tissue Can do fixed, unprocessed Phosphatongstic acid hematoxylin Fibrin, black Vierhoff van Gieson Elastin, black

71 Special Stains VI Luxol Fast Blue Myelin, blue Bodian s Axons, black Combos: LFB/HE, LFB/Bodians, LFB/PAS

72 Luxol Fast Blue Myelin