Armed Forces Institute of Pathology (AFIP) - Department of Veterinary PathologyY

Histological Classification of Tumors of the Alimentary System of Domestic Animals

TUMORS OF THE UPPER ALIMENTARY TRACT
1 Epithelial Tumors: 1.1 Benign; 1.1.1 Viral filiform papilloma; 1.1.2 Squamous papilloma; 1.1.3 Viral fibropapilloma; 1.1.4 Adenoma; 1.2 Malignant; 1.2.1 Squamous cell carcinoma; 1.2.2 Verrucous (squamous) carcinoma (papillary squamous cell carcinoma); 1.2.3 Adenocarcinoma; 1.2.4 Undifferentiated carcinoma; 1.2.5 Secondary carcinoma
2 Neuroendocrine Tumors: 2.1 Carcinoid (neuroendocrine carcinoma)
3 Melanocytic Tumors: 3.1 Melanocytoma; 3.2 Malignant melanoma
4 Mesenchymal Tumors: 4.1 Benign; 4.1.1 Fibroma; 4.1.2 Leiomyoma; 4.1.3 Rhabdomyoma; 4.1.4 Tumors of vascular tissue; 4.1.4.1 Hemangioma; 4.1.4.2 Hemangioendothelioma; 4.1.4.3 Systemic hemangiomatosis (disseminated cavernous hemangioma); 4.1.4.4 Lymphangioma; 4.1.5 Benign peripheral nerve sheath tumor (schwannoma, neurilemmoma, neurofibroma); 4.2 Malignant; 4.2.1 Fibrosarcoma; 4.2.2 Leiomyosarcoma; 4.2.3 Rhabdomyosarcoma; 4.2.4 Tumors of vascular tissue; 4.2.4.1 Hemangiosarcoma (malignant hemangioendothelioma); 4.2.4.2 Hemangiopericytoma; 4.2.5 Malignant peripheral nerve sheath tumor (malignant schwannoma, neurofibrosarcoma); 4.2.6 Sarcoma associated with Spirocerca lupi in dogs; 4.2.7 Undifferentiated sarcoma; 4.3 Others
5 Granular Cell Tumors: 5.1 Benign granular cell tumor; 5.2 Malignant granular cell tumor
6 Tumors of Bone: 6.1 Benign; 6.1.1 Osteoma; 6.1.2 Ossifying fibroma; 6.1.3 Myxoma; 6.1.4 Chondroma; 6.2 Malignant; 6.2.1 Osteosarcoma; 6.2.2 Chondrosarcoma; 6.2.3 Multilobular tumor of bone; 6.3 Tumorlike lesions; 6.3.1 Fibrous dysplasia; 6.3.2 Craniomandibular osteopathy
7 Tumors of Hematopoietic and Related Tissues: 7.1 Lymphoma (lymphosarcoma, malignant lymphoma); 7.2 Plasmacytoma; 7.3 Mast cell tumor
8 Tumorlike Lesions: 8.1 Lymphoid hyperplasia; 8.2 Nasopharyngeal polyp; 8.3 Eosinophilic granuloma; 8.4 Calcinosis circumscripta
TUMORS OF ODONTOGENIC ORIGIN
1 Tumors of Odontogenic Epithelium without Odontogenic Mesenchyme: 1.1 Ameloblastoma; 1.2 Amyloid-producing odontogenic tumor; 1.3 Canine acanthomatous ameloblastoma (acanthomatous epulis)
2 Tumors of Odontogenic Epithelium with Odontogenic Mesenchyme: 2.1 Ameloblastic fibroma; 2.1.1 Ameloblastic fibro-odontoma; 2.2 Feline inductive odontogenic tumor; 2.3 Complex odontoma; 2.4 Compound odontoma
3 Tumors Composed Primarily of Odontogenic Ectomesenchyme: 3.1 Cementoma; 3.2 Cementifying fibroma
4 Tumors Derived from the Tissues of the Periodontal Ligament: 4.1 Fibromatous epulis of periodontal ligament origin
5 Cysts of the Jaw: 5.1 Dentigerous cyst; 5.2 Radicular cyst; 5.3 Ovine odontogenic cyst; 5.4 Temporal teratoma in horses
6 Tumorlike Lesions: 6.1 Odontogenic dysplasia in aging rodents and lagomorphs; 6.2 Inflammation of odontogenic structures and periodontal tissues; 6.3 Peripheral giant cell granuloma (giant cell epulis); 6.4 Gingival hyperplasia
SALIVARY GLAND TUMORS
1 Epithelial Tumors: 1.1 Benign; 1.1.1 Pleomorphic adenoma (mixed tumor); 1.1.2 Oncocytoma (oxyphil or oncocytic adenoma); 1.1.3 Canalicular adenoma; 1.1.4 Sebaceous adenoma; 1.1.5 Ductal papilloma; 1.1.6 Cystadenoma; 1.2 Malignant; 1.2.1 Acinic cell carcinoma; 1.2.2 Mucoepidermoid carcinoma; 1.2.3 Cystadenocarcinoma; 1.2.4 Adenocarcinoma; 1.2.5 Malignant myoepithelioma (myoepithelial carcinoma); 1.2.6 Carcinoma or sarcoma in pleomorphic adenoma (malignant mixed tumor); 1.2.7 Squamous cell carcinoma; 1.2.8 Undifferentiated carcinoma
2 Nonepithelial Tumors: 2.1 Lymphoma; 2.3 Mast cell tumor; 2.3 Melanocytic tumors
3 Secondary Tumors
4 Unclassified Tumors
5 Tumorlike Lesions: 5.1 Sialadenosis; 5.2 Hyperplastic masses; 5.3 Salivary gland infarction (necrotizing sialometaplasia); 5.4 Lipomatosis (fatty infiltration or lipomatous infiltration); 5.5 Postinflammatory lipomatosis (parenchymatous atrophy); 5.6 Salivary gland cysts; 5.6.1 Extravasated pseudocyst (sialocele, serocele, mucocele); 5.6.2 True salivary cyst; 5.6.3 Branchial cyst
GASTRIC TUMORS
1 Epithelial Tumors: 1.1 Adenoma; 1.1.1 Tubular adenoma; 1.1.2 Papillary (villous) adenoma; 1.1.3 Tubulopapillary (tubulovillous) adenoma; 1.2 Adenocarcinoma; 1.2.1 Tubular adenocarcinoma; 1.2.2 Papillary adenocarcinoma; 1.2.3 Tubulopapillary adenocarcinoma; 1.2.4 Mucinous adenocarcinoma; 1.2.5 Signet-ring cell carcinoma; 1.3 Squamous cell carcinoma; 1.4 Undifferentiated carcinoma
2 Neuroendocrine Tumors: 2.1 Carcinoid (neuroendocrine carcinoma)
3 Mesenchymal Tumors: 3.1 Tumors of smooth muscle; 3.1.1 Leiomyoma; 3.1.2 Leiomyosarcoma; 3.2 Nervous tissue tumors; 3.2.1 Peripheral nerve sheath tumor (neurofibroma, schwannoma); 3.2.2 Ganglioneuroma; 3.3 Tumors of fibrous tissue; 3.4 Gastrointestinal stromal tumor; 3.5 Tumors of vascular tissue; 3.6 Tumors of adipose tissue
4 Tumors of Hematopoietic and Related Tissues: 4.1 Lymphoma (lymphosarcoma, malignant lymphoma); 4.2 Plasmacytoma; 4.3 Mast cell tumor
5 Mesothelioma
6 Secondary Tumors
7 Unclassified Tumors
8 Tumorlike Lesions: 8.1 Polyps; 8.1.1 Hyperplastic polyp (regenerative polyp); 8.1.2 Inflammatory polyp (benign lymphoid polyp); 8.2 Giant rugal hypertrophy (Ménétrier disease); 8.3 Chronic idiopathic inflammatory gastritis; 8.3.1 Scirrhous eosinophilic gastritis; 8.3.2 Lymphoplasmacytic gastritis; 8.4 Pyloric stenosis
TUMORS OF THE INTESTINES
1 Epithelial Tumors: 1.1 Benign; 1.1.1 Adenoma; 1.2 Malignant; 1.2.1 Acinar adenocarcinoma; 1.2.2 Papillary adenocarcinoma; 1.2.3 Mucinous adenocarcinoma; 1.2.4 Signet-ring cell carcinoma; 1.2.5 Undifferentiated carcinoma; 1.2.6 Adenosquamous carcinoma
2 Neuroendocrine Tumors: 2.1 Carcinoid (neuroendocrine carcinoma); 2.2 Adenocarcinoid
3 Tumors of Hematopoietic and Related Tissues: 3.1 Lymphoma (lymphosarcoma, malignant lymphoma); 3.1.1 Extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma); 3.1.2 Large granular lymphoproliferative disorder (granular cell lymphoma, globular lymphocyte tumor, granulated round cell tumor); 3.1.3 Intestinal T-cell lymphoma; 3.2 Plasmacytoma; 3.3 Mast cell tumor
4 Mesenchymal Tumors: 4.1 Benign; 4.1.1 Leiomyoma; 4.1.2 Benign peripheral nerve sheath tumor (neurofibroma, schwannoma); 4.1.3 Ganglioneuroma; 4.1.3.1 Ganglioneuromatosis; 4.1.4 Hemangioma; 4.1.5 Lipoma; 4.2 Malignant; 4.2.1 Hemangiosarcoma; 4.2.2 Leiomyosarcoma; 4.2.3 Gastrointestinal stromal tumor; 4.2.4 Malignant peripheral nerve sheath tumor; 4.2.5 Osteosarcoma; 4.2.6 Chondrosarcoma; 4.2.7 Liposarcoma
5 Secondary Tumors
6 Unclassified Tumors
7 Tumorlike Lesions: 7.1 Polyps; 7.1.1 Adenomatous polyp; 7.1.2 Papillary (villous) polyp; 7.1.3 Hamartomatous polyp; 7.1.4 Inflammatory polyp; 7.1.5 Juvenile polyposis; 7.2 Porcine proliferative enteritis; 7.3 Malformations; 7.3.1 Diverticulum; 7.3.1.1 Meckel's diverticulum; 7.3.2 Intestinal duplication; 7.4 Heterotopia; 7.4.1 Heterotopic gastric mucosa; 7.4.2 Heterotopic pancreas; 7.5 Inflammatory bowel disease; 7.5.1 Lymphoplasmacytic enteritis; 7.5.2 Scirrhous eosinophilic enteritis
TUMORS OF THE PANCREAS
1 Exocrine Epithelial Tumors: 1.1 Benign; 1.1.1 Ductal (tubular) adenoma; 1.1.2 Acinar adenoma; 1.2 Malignant; 1.2.1 Ductal (tubular) adenocarcinoma; 1.2.2 Acinar cell carcinoma; 1.2.3 Undifferentiated (anaplastic) carcinoma
2 Endocrine Tumors (Neuroendocrine Tumors): 2.1 Islet cell adenoma; 2.2 Islet cell carcinoma
3 Nonepithelial Tumors
4 Secondary Tumors
5 Unclassified Tumors
6 Tumorlike Lesions: 6.1 Nodular hyperplasia of acinar cells; 6.2 Ductal hyperplasia; 6.3 Chronic pancreatitis; 6.4 Heterotopic pancreas (ectopic pancreas); 6.5 Pancreatic steatitis; 6.6 Cysts; 6.6.1 Congenital cysts; 6.6.2 Acquired retention cyst; 6.6.3 Pseudocyst; 6.7 Nesidioblastosis
TUMORS OF THE LIVER AND GALLBLADDER
Tumors of the Liver
1 Epithelial Tumors: 1.1 Benign; 1.1.1 Hepatocellular adenoma; 1.1.2 Biliary adenoma (cholangioma); 1.1.2.1 Biliary cystadenoma; 1.2 Malignant; 1.2.1 Hepatocellular carcinoma; 1.2.2 Cholangiocarcinoma (biliary carcinoma, cholangiocellular carcinoma); 1.2.2.1 Biliary cystadenocarcinoma; 1.2.3 Hepatocholangiocarcinoma; 1.2.4 Hepatoblastoma
2 Neuroendocrine Tumors: 2.1 Carcinoid (neuroendocrine carcinoma)
3 Mesenchymal Tumors: 3.1 Benign; 3.1.1 Myelolipoma; 3.1.2 Hemangioma; 3.2 Malignant; 3.2.1 Hemangiosarcoma; 3.2.2 Others
4 Tumors of Hematopoietic and Related Tissues: 4.1 Lymphoma; 4.2 Myeloid neoplasms; 4.2.1 Histiocytic sarcoma/malignant histiocytosis; 4.3 Mast cell tumor
5 Unclassified Tumors
6 Secondary Tumors
7 Tumorlike Lesions: 7.1 Nodular hepatocellular hyperplasia; 7.2 Regenerative hepatocellular hyperplasia; 7.3 Vascular hamartoma; 7.4 Telangiectasis (peliosis hepatis); 7.5 Biliary hamartoma
Tumors of the Gallbladder
1 Epithelial Tumors: 1.1 Benign; 1.1.1 Gallbladder adenoma; 1.1.2 Leiomyoma; 1.2 Malignant; 1.2.1 Gallbladder adenocarcinoma
2 Tumorlike Lesions: 2.1 Cystic hyperplasia of the gallbladder (adenomatosis, adenomatous polyposis)
ANAL AND PERIANAL TUMORS
1 Epithelial Tumors: 1.1 Benign; 1.1.1 Squamous papilloma; 1.1.2 Adenoma of rectal type; 1.1.3 Hepatoid (perianal or circumanal) gland adenoma; 1.1.4 Anal sac gland adenoma (adenoma of the apocrine glands of the anal sac); 1.1.5 Sebaceous adenoma; 1.1.6 Apocrine adenoma; 1.2 Malignant; 1.2.1 Squamous cell carcinoma; 1.2.2 Mucoepidermoid carcinoma; 1.2.3 Adenocarcinoma of rectal type; 1.2.4 Hepatoid (perianal or circumanal) gland epithelioma; 1.2.5 Hepatoid (perianal or circumanal) gland carcinoma; 1.2.6 Anal sac gland carcinoma (carcinoma of the apocrine glands of the anal sac); 1.2.7 Sebaceous carcinoma; 1.2.8 Apocrine carcinoma; 1.2.9 Undifferentiated carcinoma
2 Mesenchymal Tumors
3 Melanocytic Tumors
4 Tumors of Hematopoietic and Related Tissues
5 Transmissible Venereal Tumor
6 Unclassified Tumors
7 Secondary Tumors
8 Tumorlike Lesions: 8.1 Hyperplasia of perianal glands; 8.2 Hyperplasia of rectal-type glands (colorectal polyp)
TUMORS OF SEROSAL SURFACES (PLEURA, PERICARDIUM, PERITONEUM, AND TUNICA VAGINALIS)
1 Tumors of Mesothelium: 1.1 Benign mesothelioma; 1.1.1 Predominantly epithelioid benign mesothelioma; 1.1.2 Predominantly fibrous (spindle cell) benign mesothelioma; 1.1.3 Biphasic (mixed) benign mesothelioma; 1.2 Malignant mesothelioma; 1.2.1 Predominantly epithelioid malignant mesothelioma; 1.2.2 Predominantly fibrous (spindle cell) malignant mesothelioma; 1.2.3 Biphasic (mixed) malignant mesothelioma
2 Other Primary Tumors
3 Unclassified Tumors
4 Secondary Tumors
5 Tumorlike Lesions: 5.1 Tumorlike activated mesothelium