Table of contents

List of Contributors xiii

Preface xiv

Acknowledgments xv

1 Pathology of the Eye and Periocular Tissues 1

Joseph S. Haynes

Introduction 1

Prefixation Preparation 1

Fixation of Eyes for Histopathology 1

Sectioning 2

Processing and Staining 2

Ocular Structure and Development 2

Cornea 3

General Corneal Reactions to Injury 4

Developmental and Degenerative Corneal Disease 5

Corneal Dermoid 5

Corneal Erosions and Ulcers 5

Corneal Sequestration 7

Corneal Endothelial Dystrophy and Mineralization 8

Corneal Stromal Dystrophy and Mineralization 8

Inflammatory Disease of the Cornea 8

Keratitis 8

Keratitis sicca 9

Canine Pannus Keratitis (Chronic Superficial Keratitis) 10

Feline Herpetic Keratitis 10

Feline Eosinophilic Keratitis 10

Mycotic Keratitis 11

Equine Corneal Stromal Abscess 11

Uvea 11

General Uveal Reactions to Injury 12

Developmental and Degenerative Uveal Disease 13

Goniodysgenesis and Pectinate Ligament Dysplasia 14

Persistent Pupillary Membrane 14

Choroidal Hypoplasia 14

Hypertensive Vasculopathy 15

Inflammatory Disease of the Uvea and Ocular 15

Uveitis 15

Lymphoplasmacytic Anterior Uveitis 16

Phacoclastic Uveitis/Endophthalmitis 19

Phacolytic Uveitis 19

Equine Recurrent Uveitis 19

Uveitis Due to FIP Coronavirus 19

Canine Uveodermatologic Syndrome (VKH-like Syndrome) 19

Pigmentary Uveitis 20

Endophthalmitis and Panophthalmitis 20

Bacterial Endophthalmitis 22

Ocular Blastomycosis 22

Ocular Cryptococcosis 22

Ocular Coccidioidomycosis 22

Ocular Histoplasmosis 24

Ocular Protothecosis 24

Lens 25

General Lens Reactions to Injury 25

Lens Luxation 25

Developmental and Degenerative Disease of the Lens 25

Microphakia and Aphakia 25

Persistent Pupillary Membrane, Persistent Primary (Hyperplastic) Vitreous, Persistent Posterior Tunica Vasculosa Lentis, and Persistent Hyaloid Artery 26

Cataract 27

Inflammatory Disease of the Lens 28

Phacitis 28

Retina 29

General Retinal Reactions to Injury 30

Developmental and Degenerative Retinal Disease 30

Retinal Dysplasia 30

Lysosomal Storage Diseases 30

Cystic Retinal Degeneration 31

Inherited Retinal Dysplasia and/or Degeneration (Progressive Retinal Atrophy) 31

Nutritionally Induced Retinopathy 32

Toxic Retinopathy 32

Ischemic and Infarctive Retinopathy 33

Glaucoma 33

Sudden Acquired Retinal Degeneration Syndrome 34

Retinal Detachment 35

Inflammatory Disease of the Retina 36

Retinitis 36

Optic Nerve 36

Developmental and Degenerative Disease of the Optic Nerve 36

Hypoplasia of the Optic Nerve and/or Optic Chiasm 36

Axonal Degeneration and Atrophy of the Optic Nerve 36

Cavitation of Optic Disk 36

Canine Ocular Gliovascular Syndrome 37

Inflammatory Disease of the Optic Nerve 37

Optic Neuritis 37

Granulomatous Meningoencephalitis 38

Sclera 38

Developmental and Degenerative Scleral Disease 39

Scleral Ectasia 39

Inflammatory Disease of the Sclera 39

Lymphoplasmacytic Scleritis 39

Nodular Granulomatous Episcleritis and Necrotizing Scleritis 40

Eyelids,Conjunctiva and Retrobulbar Tissues 40

Developmental Disease of the Eyelids 40

Inflammatory Disease of the Eyelids 40

Granulomatous Blepharitis/Meibomian Adenitis 40

Marginal Nodular Blepharitis/Meibomian Adenitis 42

Inflammatory Disease of the Conjunctiva, Membrana Nictitans, and Retrobulbar Tissues 42

Conjunctivitis 42

Nodular Granulomatous Episcleritis/Conjunctivitis 42

Periocular/Retrobulbar Cellulitis/Abscess 42

Neoplasia of the Eye and Periocular Tissues 43

Neoplasia of the Cornea 43

Neoplasia of the Uvea 45

Intraocular Melanoma and Uveal Melanocytosis 45

Iridociliary Tumors 45

Anterior Uveal Sarcoma of Blue-Eyed Dogs 46

Intraocular Osteosarcoma 46

Intraocular Adenocarcinosarcoma (Malignant Mixed Tumor) 48

Lymphoma 48

Neoplasia of the Lens 50

Trauma-Induced Intraocular Sarcoma of Cats 50

Neoplasia of the Retina 50

Neoplasia of the Eyelids 50

Palpebral Melanocytoma and Malignant Melanoma 50

Squamous Cell Carcinoma 50

Squamous Papilloma 50

Meibomian Gland Tumors 52

Neoplasia of the Conjunctiva and Membrana Nictitans 52

Squamous Cell Carcinoma 52

Adenocarcinoma of Gland of Third Eyelid (Membrana Nictitans) 54

Epibulbar Melanoma 54

Neoplasia of Retrobulbar Tissues 54

Retrobulbar Meningioma 54

Retrobulbar Peripheral Nerve Sheath Tumor 55

Lymphoma 55

Adenoma/Adenocarcinoma of Lacrimal Gland or Zygomatic Salivary Gland 55

Canine Orbital Lobular Adenoma 57

References and Additional Readings 57

2 Pathology of the Bones and Joints 59

Joseph S. Haynes

Introduction 59

Specimen Preparation, Fixation, and Demineralization 59

Bone Structure and Physiology 60

Development of Bone and Cartilage 61

Basic Reactions of Bone to Injury 62

Hypoplastic/Dysplastic Bone Growth 62

Loss of Bone 63

Excessive Production of Bone 63

Osteonecrosis 64

Inflammation of Bone 65

Neoplasia of Bone 68

Joint Structure and Physiology 68

Basic Reactions of Joints to Injury 68

Degenerative Changes in Articular Cartilage 69

Inflammation of Articular Cartilage and Chondronecrosis 70

Inflammation of the Synovial Membrane and Joint Capsule 71

Diseases of Bone 72

Developmental Disorders and Anomalies 72

Osteochondrosis 72

Physeal Dysplasia in Cats 73

Chondrodysplasia 73

Osteochondromatosis (Multiple Cartilaginous Exostoses) 73

Hyperostotic Diseases of Bone 74

Hypertrophic (Pulmonary) Osteopathy 74

Canine Hepatozoonosis 74

Hyperostoses of Nutritional Origin 74

Hyperostoses of Unknown Cause 74

Inflammatory Diseases of Bone 75

Osteomyelitis Caused by Bacterial Infection 75

Osteomyelitis Caused by Fungal Infection 76

Canine Metaphyseal Osteopathy (Canine Hypertrophic Osteodystrophy) 76

Osteonecrosis and Bone Infarction 77

Necrosis of the Femoral Head and Legg–Calve–Perthes Disease 77

Bone Infarction 77

Neoplasia of Bone 78

Osteoma 78

Osteosarcoma 78

Chondroma 80

Chondrosarcoma 82

Multilobular Tumor of Bone 82

Osteochondroma 83

Giant Cell Tumor 83

Multiple Myeloma 83

Chordoma 84

Hemangiosarcoma 84

Ossifying Fibroma 84

Diseases of Joints 85

Osteochondrosis Dissecans 85

Infectious Arthritis due to Bacteria 86

Lyme Disease 86

Autoimmune and Immune-Mediated Arthritis 86

Chronic Osteoarthritis 86

Neoplasms of Joints 87

References and Additional Readings 89

3 Pathology of the Skin 90

Joseph S. Haynes

Introduction 90

Specimen Preparation and Fixation 90

Basic Reactions of Skin to Injury 90

Inflammation of the Skin: Dermatitis 90

Microscopic Patterns of Cutaneous Inflammation 91

Acute Dermatitis 91

Chronic Dermatitis 94

Abnormal Keratinization 95

Alopecia 96

Abnormal Pigmentation 96

Diseases of the Skin 96

Developmental Disorders and Anomalies of the Skin 96

Ichthyosis 96

Primary Seborrhea 96

Hyperplastic Dermatosis of the West Highland White Terriers 97

Zinc Responsive Dermatosis 97

Black-Hair Follicular Dysplasia and Color Mutant Alopecia 98

Collagen Dysplasia 98

Degenerative, Atrophic, and Necrotizing Diseases of the Skin 99

Endocrine-Related Disease 99

Superficial Necrolytic Dermatitis 100

Toxic Epidermal Necrolysis 101

Cutaneous Infarction 101

Inflammatory Diseases of the Skin 101

Allergic Skin Diseases 101

Feline Miliary Dermatitis 103

Autoimmune Skin Diseases 107

Bacterial Skin Disease 111

Pyoderma 112

Nocardiosis and Actinomycosis 112

Fungal Skin Disease 112

Dermatophytosis 112

Additional Fungal Skin Disease 112

Parasitic Skin Disease 113

Demodectic Mange 113

Sarcoptic and Notoedric Mange (Scabies) 115

Cutaneous Habronemiasis 116

Miscellaneous Inflammatory Skin Diseases 116

Acral Lick Dermatitis 116

Chronic Otitis Externa 117

Pyogranulomatous Panniculitis 117

Sebaceous Adenitis 117

Neoplasms and Cystic Lesions of the Skin 117

Epithelial Neoplasms 117

Squamous Papilloma 117

Inverted Viral Squamous Papilloma 119

Cutaneous Horn 119

Canine and Feline Viral Plaque 119

Actinic Keratosis 119

Squamous Cell Carcinoma 120

Squamous Cell Carcinoma 121

Basosquamous Carcinoma 124

Infundibular Keratinizing Acanthoma (Intracutaneous Cornifying Epithelioma) 124

Subungual Keratoacanthoma 125

Trichoblastoma (Basal Cell Tumor) 125

Trichoblastoma 125

Trichoepithelioma 125

Pilomatricoma 129

Apocrine Gland Tumors 131

Anal Sac Apocrine Adenocarcinoma 132

Ceruminous Gland Tumors 133

Sebaceous Gland Tumors 133

Hepatoid/Perianal Gland Tumors 135

Eccrine Gland Tumors 135

Melanotic Tumors 137

Mesenchymal Neoplasms 138

Canine Soft Tissue Sarcomas 138

Equine Sarcoid 140

Feline Sarcoid 141

Canine Keloidal Fibroma 141

Feline Giant Cell Sarcoma 141

Feline Vaccination Site Sarcoma 141

Cutaneous Hemangioma and Hemangiosarcoma 141

Round Cell Neoplasms and Reactive Proliferations 143

Cutaneous Lymphoma 143

Cutaneous Histiocytic Diseases 143

Canine Persistent and Recurrent Cutaneous Histiocytomas 144

Cutaneous Plasmacytoma 148

Canine Cutaneous Mast Cell Tumors 148

Canine Subcutaneous Mast Cell Tumors 151

Feline Cutaneous Mast Cell Tumors 151

Equine Cutaneous Mast Cell Tumors 151

Other Masses, Cysts, and Cyst-like Structures 153

Follicular Cyst 153

Infundibular Cyst 153

Isthmus Cyst 154

Matrical Cyst 154

Hybrid Cyst 154

Dermoid Cyst 155

Apocrine Gland Cyst 155

Canine Apocrine Cystomatosis 156

Feline Ceruminous Cystomatosis 156

Calcinosis Circumscripta 156

Follicular Hamartoma 156

Fibroadnexal Hamartoma 156

Collagenous Hamartoma 158

Acrochordon (Skin Tag) 158

References and Additional Readings 159

4 Pathology of the Male Reproductive System 160

Michael J. Yaeger

Prostate 160

Introduction 160

Developmental and Degenerative Diseases 160

Prostatic Hypoplasia/Atrophy 160

Prostatic Hyperplasia/Hypertrophy 160

Prostatic Cysts 162

Prostatic Squamous Metaplasia 162

Prostatic Inflammatory Diseases 162

Acute and Chronic Bacterial Prostatitis 162

Prostatic Abscessation 163

Prostatic Neoplasia 163

Prostatic Adenocarcinoma 164

Prostatic Transitional Cell Carcinoma 164

Testes and Epididymis 164

Developmental and Degenerative Diseases 166

Testicular Hypoplasia 166

Testicular Atrophy/Degeneration 166

Testicular and Epididymal Inflammatory Disease 166

Infectious Orchitis and Epididymitis 166

Spermatocele and Sperm Granulomas 167

Testicular Neoplasia 167

Sertoli Cell Tumors 169

Seminoma 169

Interstitial Cell (Leydig) Tumor 169

Biologic Behavior of Canine Testicular Tumors 171

Feline Testicular Tumors 171

Equine Testicular Tumors 171

Penis and Prepuce 171

Introduction 171

Developmental and Degenerative Diseases 172

Inflammatory Diseases 172

Balanitis, Posthitis and Balanoposthitis 172

Neoplastic Diseases 172

Equine Penile Neoplasia 172

Equine Penile Squamous Cell Carcinoma 173

Equine Penile Sarcoid 173

Equine Penile Melanoma 173

Bovine Penile Fibropapilloma 174

Canine Penile Papilloma 174

Canine Transmissible Venereal Tumor 174

References and Additional Readings 176

5 Pathology of the Female Reproductive System 178

Michael J. Yaeger

Ovaries 178

Introduction 178

Developmental and Degenerative Diseases 178

Ovarian Cysts 178

Ovarian Inflammation 179

Oophoritis and Salpingitis 179

Ovarian Neoplasia 179

Germ Cell Tumors/Dysgerminoma and Teratoma 180

Dysgerminoma 180

Teratoma 181

Sex Cord-Stromal Tumors 181

Epithelial Tumors 182

Uterus and Vagina 183

Introduction 183

Developmental and Degenerative Diseases 184

Endometrial Hyperplasia/Cysts 184

Serosal Inclusion Cysts 184

Cystic Endometrial Hyperplasia 184

Pseudoplacentational Endometrial Hyperplasia 184

Adenomyosis 185

Subinvolution of Placental Sites 185

Uterine Inflammation 186

Endometritis, Metritis, Perimetritis, and Pyometra 186

Endometrial Biopsies 186

Uterine and Vaginal Neoplasia 189

Endometrial Polyps 189

Uterine Tumors 189

Vaginal and Vulvar Tumors 190

Mammary Gland 191

Introduction 191

Developmental and Degenerative Diseases 191

Feline Mammary Fibroadenomatous Hyperplasia 191

Mammary Duct Ectasia and Hyperplasia 191

Inflammatory Disease 192

Mastitis 192

Mammary Neoplasia 192

Rat Mammary Neoplasia 192

Fibroadenoma 192

Canine Mammary Neoplasia 193

Mammary Adenoma and Complex Mammary Adenoma (Mixed Tumor) 193

Malignant Mammary Neoplasia 194

Mammary Adenocarcinoma, Sarcoma, and Carcinosarcoma 194

Feline Mammary Neoplasia 196

Feline Mammary Carcinoma/Adenocarcinoma 197

References and Additional Readings 197

Index 199