Selected Gross Pathology of the Cat

6/14/2011
Selected Gross Pathology of
the Cat
Bruce Williams, DVM, DACVP
Dept. of Veterinary Pathology
AFIP, Washington DC
williamsb@afip.osd.mil
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SELECTED GROSS PATHOLOGY OF THE CAT
Instructor:
Bruce H. Williams, DVM, DACVP
Joint Pathology Center
(301 295-6193
Email: Bruce.williams2@amedd.army.mil
PURPOSE
The purpose of this 3-hour block of instruction is to gain knowledge and experience in
the gross diagnosis of diseases of the domestic cat. (Felix silvestris catus). Of course,
the study of disease in this species far exceeds what can be presented in a three hour
block of time, but I will attempt to cover a number of diseases of interest. In some
cases, inclusion or exclusion from this collection was the result of the availability of highquality photographs. I am a firm believer that one can learn far more from one excellent
photograph of a single entity, than from many poor ones. If the only available image is
of poor quality, the image won’t leave a lasting impression, and the student learns
nothing.
I have included a brief morphologic diagnosis for each entity. The formulation of
concise, accurate morphologic diagnoses is a major pursuit of every good pathologist,
especially those who seek certification in this specialty. The formulation of a good
morphologic diagnosis is a learned skill; for those seeking additional experience in this
endeavor, I would suggest attendance at the annual AFIP Descriptive Pathology Course
in Washington D.C.
.
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Slide Organ No. 1. Condition Morphologic Diagnosis Notes INTRODUCTION 2. 3. CARDIOVASCULAR SYSTEM 4. Heart Dilatative cardiomyopathy Bilateral ventricular enlargement with pleural effusion Look for pleural effusion and chronic passive congestion in the liver. 5. Heart Hypertrophic cardiomyopathy Diffuse hypertrophy of the interventricular septum and the left ventricular free wall May be genetic or secondary to hyperthyroidism 6. Distal aorta Aortic thromboembolism Focally extensive thomboembolism of the distal aorta with multiple renal infarcts Much more common in dilatative forms of cardiomyopathy 7. Hind feet 8. Heart, right Cyanosis of distal extremeities Dirofilaria immitis
Focally extensive verminous endarteritis Microfilaremia is rarely seen and aberrant worm migration is more common. Dirofilaria immitis
Focal filarid parasite in third ventricle Aberrant migration is more common in aberrant hosts. ventricle and pulmonary artery 9. Cerebrum, third ventricle HEMATOPOIETIC SYSTEM
10. 11. Thymus Malignant lymphoma
Thymic Lymphoma, pleural effusion, and pulmonary congestion and edema. 12. Mesenteric Malignant lymphoma
Mesenteric lymph node; intestine: Malignant lymphoma Malignant lymphoma
The most common neoplasm Lymphoma has a typical in each of these systems creamy white, bulging lymph node; intestine 13. Heart, spinal cord, haired 2
Most common malignancy in the cat. High incidence in association with FeLV infection, especially FeLv‐
B. FOCMA antibodies found on membranes of FeLV‐transformed lymphocytes skin,kidney lymphoma with the exception of skin
appearance on cut surface in any organ due to the high number of cells and absence of stroma. 14. Liver, spleen Malignant lymphoma
Splenic and hepatic lymphoma May also result in generalized organ enlargement. Need to rule out mast cell tumor in this location as well (less common in liver, though). 15. Thymus Thymoma Thymoma
Inset shows thymoma‐
associated exfoliative skin disease. 16. Abdominal Feline infectious peritonitis Diffuse lymphohistocytic serosal vasculitis and exudative serositis High protein “honey‐like” exudates in abdominal cavity and fibrin strands. 17. Liver Feline infectious peritonitis Diffuse severe fibrinous perihepatitis The end result of abundant fibrin on abdominal organ suggests the existence of severe vasculitis. 18. Abdominal Feline infectious anemia (Hemobartonella felis) Generalized icterus with marked splenomegaly The most common cause of hemolytic anemia in the cat. Cytauxzoon felis
Multifocal pulmonary thrombosis with hemorrhage; hepatomegaly Cytuxzoon has two stages of schizogony – the first is in macrophages and the second in erythrocytes. However, the macrophages get so large, they sludge and thrombose capillaries, especially in the lungs. This ist he stage where most cats die. viscera viscera 19. Lung, liver 20. 21. Teeth GASTROINTESTINAL SYSTEM Osteoclastic resorptive Osteoclastic resorptive 3
Partial to full thickess dentinal pitting, often in 22. Lip, tongue lesion lesion
cheek teeth. Eosinophilic granuloma Focally extensive lymphoplasmacytic cheilitis; multifocal eosinophilic and proliferative glossitis Although a member of the “eosinophilic granuloma complex”, the chronic erosive lesions of the lips (“rodent ulcers”) rarely have any eosinophils left in them. Focally extensive eosinophilic and granulomatous stomatitis Not all “rodent ulcers” are ulcerative. Marked cellular infiltrates and granulation tissue may causea lesion which appears proliferative. 23. Sublingual gingiva 24. Tongue Feline calicivirus
Diffuse vesicular and ulcerative glossitis Virulent strain of feline calicivirus has necrosis of skin and multiple organ dysfunction 25. Palate Plasma cell stomatitis
Bilaterally symmetrical ulcerative and plasmacytic stomatitis Characteristically located at the glossopalatine arch (faucitis), rule out “kissing ulcers”, an inflammatory response to plaque. 26. Small intestine Feline panleukopenia
Diffuse necrohemorrhagic enteritis Feline parvovirus is the # most common cause of reddened intestines; virus wipes out villar crytps resulting in high mortality. 27. Jejunum String foreign body
Linear intestinal ulceration with plication “Accordion‐pleating” of the intestine is a characteristic finding. 28. Jejunum Taenia taeniaformis, Toxocara cati or Toxascaris leonina Focally extensive catarrhal and verminous enteritis 29. Jejunum Ancylostoma tubaeformae or braziliense Multifocal to coalescing ulcerative and hemorrhagic enteritis 4
Ancylostoma braziliense
may cause human infections. 30. Jejunum Histoplasma capsulatum Diffuse granulomatous enteritis Rule out diffuse systemic fungal disease, M. avium . 31. Colon Megacolon, Manx spinal cord deformity Diffuse colonic neuropathy and sacrococcygeal spinal cord dysplasia Megacolon may be the result of nerve damage, congenital nerve defects or colonic or anal atresia. Inset: Manx spinal cord dysplasia 32. Oral cavity, Squamous cell carcinoma Maxillary and lingual squamous cell carcinoma SCCA is the most common oral malignancy in cats, look under the tongue. 33. Jejunum Malignant lymphoma
Jejunal lymphoma
Rule out mast cell tumor. This tumor generally expands the intestinal call and is creamy white on incision. 34. Colon Colonic adenocarcinoma Colonic adenocarcinoma
Epithelial neoplasms are have a “napkin‐ring” effect due to desmoplasia. Proximal bowel will likely be dilated. ventral surface of tongue 35. HEPATOBILIARY AND PANCREATIC SYSTEMS 36. Liver Hepatic lipidosis
Diffuse severe hepatic lipidosis Sequelae are icterus, hepatic failure, and hepatic encephalopathy. 37. Liver Telangiectasia
Diffuse hepatic telangiectasia, multifocal nodular exocrine pancreatic hyperplasia Telangiectasia is an incidental finding in cats and cattle. Pancreatic exocrine hyperplasia is a common aging change 38. Liver Malignant lymphoma
Hepatic lymphoma
DDx include lymphocytic cholangiohepatitis and granulomatous disease. 39. Liver Biliary cystadenoma
Biliary cystadenoma
Usually affects one lobe
40. Liver Cholangiocarcinoma
Hepatic cholangiocarcinoma
Multilobular with umbilicated centers, but 5
difficult to differentiate from other metastatic neoplasms 41. Abdominal cavity 42. Mesenteric fat Pancreatic exocrine carcinoma Pancreatic exocrine carcinoma Tends to “seed” widely. In the cat, a schirrous response to explanted tumors is known as “carcinomatosis”. Necrotizing steatitis
Diffuse necrotizing steatitis
Yellow‐brown, hard, painful mesenteric and subcutaneous fat due low‐
Vit E or hi‐unsaturated fat diets. INTEGUMENTARY SYSTEM
43. 44. Haired skin, chin Feline acne Multifocal to coalescing pyogranulomatous folliculitis, furunculosis, and comedone formation 45. Haired skin, face Notoedres cati
Diffuse severe hyperkeratotic facial and auricular dermatitis Otodectes doesn’t get this bad! 46. Haired skin, face Microsporum canis
Multifocal to coalescing hyperkeratotic and proliferative dermatitis Deep dermatophyte infection will cause draining nodules 47. Haired skin, Sporothrix schenkii
Multiofocal to coalescing pyogranulomaout dermatitis and cellulitis DDx: Cutaneous hi‐
mortality calicivirus infection Feline calicivirus
Focally extensive necrotizing dermatitis A relatively new form of calicivirus, identified in shelters in California, adds necrotizing cellulitis and a 60% mortality to the many lesions that can be seen with caliciviral infections. Multifocal to coalescing C. grubii and C. gatti can cause infection in and ear pinna and head 48. Haired skin, ear 49. Haired skin, face Cryptococcus 6
neoformans
granulomatous dermatitis
immunocompetent hosts.
50. Haired skin Feline ulcerative dermatitis syndrome Focally extensive atrophic
alopecia Look for linear fibrosis across bottom of biopsy. Thought to possibly be a reaction to vaccines. 51. Haired skin Feline skin fragility syndrome Focally extensive severe atrophic dermatitis FSFS has been associated with a number of conditions, most commonly Cushing’s disease, but also diabetes mellitus and FIP. 52. Haired skin Eosinophilic plaques
Multifocal to coalescing eosinophilic and granulomatous dermatitis No trouble finding eosinophils in this lesion! 53. Haired skin Linear granuloma
Multifocal to coalescing eosinophilic and granulomatous dermatitis The back of the hindleg is a very characteristic place for this lesion. 54. Foot pad Plasmacytic pododermatitis Focally extensive plasmacytic pododermatitis May be accompanied by plasmacytic stomatitis. 50% of cases are FeLV+ 55. Haired skin, Mosquito‐bite hypersensitivity Focally extensive lymphoplasmacytic, eosinophilic, and ulcerative nasal dermatitis Type 1 hypersensitivity reaction Vaccine‐site fibrosarcoma Cutaneous fibrosarcoma
Very aggressive fibrosarcoma arising at site of previous vaccination Vaccine‐site fibrosarcoma Skeletal muscle fibrosarcoma Microscopic examination may reveal inflammatory foci containing histiocytes with vaccine material. 58. Haired skin Pigmented and cystic basal cell tumor Cutaneous pigmented and cystic basal cell tumor This is the most common skin tumor in the cat. 59. Haired skin, Feline squamous cell carcinoma Cutaneous squamous cell carcinoma Commonly seen on face,ears and other thinly nose 56. Haired skin, dorsum between shoulder blades 57. Hindlimb, quadriceps muscle preauricular 7
areas 60. Haired, skin, planum nasale 61. Haired skin, ventral abdomen 62. Haired skin haired areas of white cats
Squamous cell carcinoma Cutaneous squamous cell carcinoma Feline ventral abdominal angiosarcoma Ventral abdominal cutaneous lymphagiosarcoma This is a typical location and appearance for this unique neoplasm which leaks lymph through the skin. Giant cell tumor of soft parts Giant cell tumor of soft parts
Characteristic storiform pattern can be “seen” here grossly. May also arise in tendon sheath or bone. NERVOUS SYSTEM
63. 64. Cerebellum (normal control below) 65. Cerebrum, lateral ventricles 66. Cerebrum, telencephalon 67. Cerebrum Feline panleukopenia virus Diffuse cerebellar hypoplasia
Infection in utero
damages cells of external granular cell layer Feline infectious peritonitis Multifocal to coalescing pyogranulomatous ventriculitis with internal hydrocephalus Granulomatous inflammation obstructing CSF outflow at level of mesencephalic aqueduct Cryptococcus neoformans Multifocal granulomatous encephalitis (actually often very little inflammation) Classic soap‐bubble lesions in the brain of the cat and horse are due to ineffective immune response. Feline ischemic encephalopathy Unilateral cerebral necrosis and hemorrhage Characteristically area of middle cerebral artery – associated with Cuterebra larvae (inset), but exact mechanism not elucidated Unilateral cerebral atrophy with collapse 68. 69. Cerebellum, Cerebellar coning
Cerebellar edema and herniation through foramen magnum Results of intracranial swelling – may depress the medullary respiratory centers Meningioma
Cerebral meningioma
Most common brain vermis 70. Cerebrum 8
tumor of cat 71. Cerebrum Astrocytoma
Cerebral astrocytoma
72. Eye, iris Iridal lymphoma
Iridal lymphoma
73. Eye, iris Diffuse iridal melanoma Iridal melanoma
This lesion progresses over many years, the iris thickens, and may result in secondary glaucoma. 74. Eye, globe Post‐traumatic ocular sarcoma Diffuse ocular sarcoma with pthisis bulbi Following trauma, the posterior lens epithelium may undergo malignant transformation in the cat. 75. Eyes Feline infectious peritonitis Diffuse fibrinous and suppurative anterior uveitis Hypopyon – cells and inflammatory material generally settle to the bottom of the eye. Look for vascular lesions in orbital soft tissues outside of the globe. 76. Eyes, iris Acquired portosystemic shunts Iridal pigmentation
The “bronze eyes” of this cat are uniquely associated with PSS in the cat. 77. Middle ear Middle ear polyp
Nasopharyngeal polyp
Secondary to chronic sinusitis or eustachitis. 78. REPRODUCTIVE SYSTEM
79. 80. Uterus Uterine Torsion
Unilateral uterine torsion and venous infarction 81. Uterus Cystic endometrial hyperplasia Diffuse cystic endometrial hyperplasia 82. Uterus Pyometra Diffuse suppurative endometritis 9
Veins are thin‐walled with lower pressure and infarct well before arteries. Usually follows endometritis or endometrial hyperplasia 83. Uterus Endometrial stromal polyp Endometrial stromal polyp
True uterine tumors very uncommon in the queen. Note the lack of 84. Mammary Mammary hyperplasia
Diffuse mammary fibroepithelial hyperplasia May follow progestogen administration. Non‐
ulcerated. glands RESPIRATORY SYSTEM
85. 86. Nasal septum Feline herpesvirus infection Diffuse necrosuppurative rhinitis Usually secondary complication with P. multocida, B. bronchiseptica and M. felis 87. Thoracic cavity Pyothorax Diffuse fibrinosuppurative pleuritis (pyothorax) Mixed bacterial infections are common with Pasteurella, Bacteoides, and Fusobacterium commonly isolated. 88. Lungs Histoplasma capsulatum Multifocal to coalescing pyogranulomatous pneumonia DDx includes other systemic fundal infection and resolving T. gondii infection 89. Lung Toxoplasma gondii
Multifocal to coalescing necrotizing and proliferative pneumonia Yes, cats can be clinically affected. The pneumonia caused by this organism can resemble fungal infections grossly in the florid reparative phase. 90. Lung Paragonimus kellicotti
Focally extensive granulomatous pneumonia with intralesional flukes Most commonly found in caudal lobes. Fish or crayfish is intermediate host. 91. Lung 92. Aelurostrongylus abstrusus Diffuse histiocytic bronchointerstitial and verminous pneumonia Usually asymptomatic, but severe infections may result in clinical disease in association with bacterial infection. and turbinates 10
93. Lung 94. Lung (cross Feline asthma
Diffuse chronic and mucoid
bronchiolitis sections) Very characteristic collars of inflammatory cells “donuts” around bronchioles. Grossly, lobules associated with affected airways are atelectatic. 95. Thoracic cavity Diaphragmatic hernia
Diaphragmatic hernia with pulmonary congestion, edema and pleural effusion Most commonly resulting from trauma. 96. Thoracic cavity Metastatic mammary neoplasia Lung, pleural cavity: Mammary adenocarcinoma, metastatic. Mammary adenocarcinoma has high malignant and metastatic potential in the cat. DDX include malignant lymphoma. URINARY SYSTEM
97. 98. Kidney Polycystic kidney disease Multiple renal cysts with end‐stage renal disease Genetic predisposition in Persian cats, may be associated with cysts in biliary and pancreatic ducts 99. Kidneys in situ Chronic interstitial nephritis (end‐stage kidney Diffuse chronic interstitial nephritis (nephrosclerosis) Sequela include parathyroid hyperplasia, chronic anemia, osteoporosis 100. Kidney, cortex Renal infarcts
Multiple acute and chronic renal infarcts 101. Kidney Pyelonephritis
Diffuse suppurative and hemorrhagic pyelonephritis Radiating hemorrhage and inflammation from the pelvis 102. Kidney Renal papillary necrosis Diffuse renal papillary necrosis Any process that impairs vasa recta circulation will do this; not just NSAIDs 103. Kidney Ethylene glycol toxicosis Multifocal hemorrhagic necrosis with crystal Oxalate toxicosis. May also be seen with Vit C 11
deposition
overdosage 104. Kidney Amyloidosis
Diffuse renal amyloidosis
Abyssinian cats are predisposed; lesions mosre severe in medulla. High prevalence in cheetahs. 105. Kidneys Malignant lymphoma
Renal lymphoma
Main gross differential is feline infectious peritonitis; rule out other metastatic neoplasms 106. Kidney Feline infections peritonitis Multifocal to coalescing pyogranulomatous renal vasculitis and nephritis Differentiate from malignant lymphoma grossly based on perivascular location of cellular infiltrate. 107. Urinary bladder Hematuria Hematuria
Urinary outflow obstruction is the most common cause (feline urologic syndrome) 108. Urinary bladder Feline urologic syndrome Cystic struvite urolithiasis with diffuse polypoid cystitis Chronic bladder infection may be a cause for stone formation ENDOCRINE SYSTEM
109.
110. Thyroid gland Adenomatous thyroid hyperplasia Bilateral adenomatous thyroid hyperplasia Most common cause of hyperthyroidism in cats. Thyrotoxicity may result in hypertrophic cardiomyopathy. 111. Parathyroid Parathyroid hyperplasia Diffuse parathyroid hyperplasia May be secondary to diet or end‐stage renal disease Pituitary carcinoma
Pituitary carcinoma
gland 112. Pituitary gland MUSCULOSKELETAL SYSTEM
113.
114. Paw Polydactyly Polydactyly
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Recessive genetic mutation which has recently been seized on by cat breeders. Hemingway must have thought it was cool. 115. Rib cage Osteogenesis imperfecta 116. Hindlimbs Multiple rib fractures
Femoral and tibial fractures with callus Defect in collagen type 1 production, with concomitant osteopenia. Look for joint, tooth, sclera abnormalities. 117. Radius, ulna Porphyria Long bone porphyria
Congenital defect of uroporphyrinogen‐3‐
cosynthetase. Concomitant anemia 118. Cervical and Vit A toxicity
Vertebral bodies, cervical and thoracic: Severe diffuse hyperostosis and spodylosis Vitamin A is stimulatory to osteoblast in adult animals, but inhibitory in young animals Feline alpha mannosidosis Facial dysmorphism with frontal done dysplasia The “bossing” of the forehead isseen in association with other defects in the flat bones in kittens with a number of storage diseases. Multiple cartilaginous exostoses Cranial and scapular osteochondromas 121. Femoral head Malignant lymphoma
Femoral malignant lymphoma 122. Digits Pulmonary adenocarcinoma 123. Distal femur Osteosarcoma
thoracic vertebrae 119. Skull and frontal bone 120. Skull, scapular neck Bone is not an uncommon site for lymphoma in cats Femoral osteosarcoma
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Can occur in any species. When compared to lymphoma, is not as dense.