WHO classification of head and neck tumors

The World Health Organizatiοn (WHO) classification of head and neck tumors is the most widely used pathologic classification system for such disorders. The current revision, part of the 4^th edition of the WHO series, was published in 2017 and is reflected in the article below ¹.

Classification

Tumors of the nasal cavity, paranasal sinuses, and skull base

• carcinomas

  • keratinizing squamous cell carcinoma

  • non-keratinizing squamous cell carcinoma

  • spindle cell (sarcomatoid) squamous cell carcinoma

  • lymphoepithelial carcinoma

  • sinonasal undifferentiated carcinoma

  • NUT carcinoma

  • neuroendocrine carcinoma

  • adenocarcinoma

    • intestinal-type adenocarcinoma

    • non-intestinal-type adenocarcinoma

• teratocarcinosarcoma

• sinonasal papillomas

  • sinonasal papilloma, inverted type

  • sinonasal papilloma, oncocytic type

  • sinonasal papilloma, exophytic type

• respiratory epithelial lesions

  • respiratory epithelial adenomatoid hamartoma

  • seromucinous hamartoma

• salivary gland tumors

  • pleomorphic adenoma

• malignant soft tissue tumors

  • fibrosarcoma

  • undifferentiated pleomorphic sarcoma

  • leiomyosarcoma

  • rhabdomyosarcoma

  • angiosarcoma

  • malignant peripheral nerve sheath tumor

  • biphenotypic sinonasal sarcoma

  • synovial sarcoma

• borderline/low-grade malignant soft tissue tumors

  • desmoid-type fibromatosis

  • sinonasal glomangiopericytoma

  • solitary fibrous tumor

  • epithelioid hemangioendothelioma

• benign soft tissue tumors

  • leiomyoma

  • hemangioma

  • schwannoma

  • neurofibroma

• other tumors

  • meningioma

  • sinonasal ameloblastoma

  • chondromesenchymal hamartoma

• hematolymphoid tumors

  • extranodal NK/T-cell lymphoma

  • extraosseous plasmacytoma

• neuroectodermal/melanocytic tumors

  • Ewing sarcoma/primitive neuroectodermal tumors

  • olfactory neuroblastoma

  • mucosal melanoma

Tumors of the nasopharynx

• nasopharyngeal carcinoma

• nasopharyngeal papillary adenocarcinoma

• salivary gland tumors

  • adenoid cystic carcinoma

  • salivary gland anlage tumor

• benign and borderline lesions

  • hairy polyp

  • ectopic pituitary adenoma

  • craniopharyngioma

• soft tissue tumors

  • nasopharyngeal angiofibroma

• hematolymphoid tumors

• notochordal tumors

  • chordoma

Tumors of the hypopharynx, larynx, trachea, and parapharyngeal space

• malignant surface epithelial tumors

  • conventional squamous cell carcinoma

  • verrucous squamous cell carcinoma

  • basaloid squamous cell carcinoma

  • papillary squamous cell carcinoma

  • spindle cell squamous cell carcinoma

  • adenosquamous carcinoma

  • lymphoepithelial carcinoma

• precursor lesions

  • dysplasia

  • squamous cell papilloma and squamous cell papillomatosis

• neuroendocrine tumors

  • well-differentiated neuroendocrine carcinoma

  • moderately differentiated neuroendocrine carcinoma

  • poorly differentiated neuroendocrine carcinoma

• salivary gland tumors

  • adenoid cystic carcinoma

  • pleomorphic adenoma

  • oncocytic papillary cystadenoma

• soft tissue tumors

  • granular cell tumor

  • liposarcoma

  • inflammatory myofibroblastic tumor

• cartilage tumors

  • chondroma and chondrosarcoma

• hematolymphoid tumors

Tumors of the oral cavity and mobile tongue

• malignant surface epithelial tumors

  • squamous cell carcinoma

• oral potentially malignant disorders and oral epithelial dysplasia

  • oral potentially malignant disorders

  • oral epithelial dysplasia

  • proliferative verrucous leukoplakia

• papillomas

  • squamous cell papilloma

  • condyloma acuminatum

  • verruca vulgaris

  • multifocal epithelial hyperplasia

• tumors of uncertain histogenesis

  • congenital granular cell epulis

  • ectomesenchymal chondromyxoid tumor

• soft tissue and neural tumors

  • granular cell tumor

  • rhabdomyoma

  • lymphangioma

  • hemangioma

  • schwannoma and neurofibroma

  • Kaposi sarcoma

  • myofibroblastic sarcoma

• oral mucosal melanoma

• salivary type tumors

  • mucoepidermoid carcinoma

  • pleomorphic adenoma

• hematolymphoid tumors

  • CD30-positive T-cell lymphoproliferative disorder

  • plasmablastic lymphoma

  • Langerhans cell histiocytosis

  • extramedullary myeloid sarcoma

Tumors of the oropharynx (base of tongue, tonsils, adenoids)

• squamous cell carcinoma

  • squamous cell carcinoma, HPV-positive

  • squamous cell carcinoma, HPV-negative

• salivary gland tumors

  • pleomorphic adenoma

  • adenoid cystic carcinoma

  • polymorphous adenocarcinoma

• hematolymphoid tumors

  • Hodgkin lymphoma

  • Burkitt lymphoma

  • follicular lymphoma

  • mantle cell lymphoma

  • T-lymphoblastic leukemia/lymphoma

  • follicular dendritic cell sarcoma

Tumors and tumor-like lesions of the neck and lymph nodes

• tumors of unknown origin

  • carcinoma of unknown primary

  • Merkel cell carcinoma

  • heterotopia-associated carcinoma

• hematolymphoid tumors

• cysts and cyst-like lesions

  • branchial cleft cyst

  • thyroglossal duct cyst

  • ranula

  • dermoid and teratoid cysts

Tumors of salivary glands

• malignant tumors

  • mucoepidermoid carcinoma

  • adenoid cystic carcinoma

  • acinic cell carcinoma

  • polymorphous adenocarcinoma

  • clear cell carcinoma

  • basal cell adenocarcinoma

  • intraductal carcinoma

  • adenocarcinoma, not otherwise specified

  • salivary duct carcinoma

  • myoepithelial carcinoma

  • epithelial-myoepithelial carcinoma

  • carcinoma ex pleomorphic adenoma

  • secretory carcinoma

  • sebaceous adenocarcinoma

  • carcinosarcoma

  • poorly differentiated carcinoma

  • lymphoepithelial carcinoma

  • squamous cell carcinoma

  • oncocytic carcinoma

  • sialoblastoma

• benign tumors

  • pleomorphic adenoma

  • myoepithelioma

  • basal cell adenoma

  • Warthin tumor

  • oncocytoma

  • lymphadenoma

  • cystadenoma

  • sialadenoma papilliferum

  • ductal papillomas

  • sebaceous adenoma

  • canalicular adenoma and other ductal adenomas

• non-neoplastic epithelial lesions

  • sclerosing polycystic adenosis

  • nodular oncocytic hyperplasia

  • lymphoepithelial sialadenitis

  • intercalated duct hyperplasia

• benign soft tissue lesions

  • hemangioma

  • lipoma/sialolipoma

  • nodular fasciitis

• hematolymphoid tumors

  • extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma)

Odontogenic and maxillofacial bone tumors

• odontogenic carcinomas

  • ameloblastic carcinoma

  • primary intraosseous carcinoma, not otherwise specified

  • sclerosing odontogenic carcinoma

  • clear cell odontogenic carcinoma

  • ghost cell odontogenic carcinoma

• odontogenic carcinosarcoma

• odontogenic sarcomas

• benign epithelial odontogenic tumors

  • ameloblastoma

    • ameloblastoma, unicystic type

    • ameloblastoma, extraosseous/peripheral type

    • metastasizing ameloblastoma

  • squamous odontogenic tumor

  • calcifying epithelial odontogenic tumor

  • adenomatoid odontogenic tumor

• benign mixed epithelial and mesenchymal odontogenic tumors

  • ameloblastic fibroma

  • primordial odontogenic tumor

  • odontoma

  • dentinogenic ghost cell tumor

• benign mesenchymal odontogenic tumors

  • odontogenic fibroma

  • odontogenic myxoma/myxofibroma

  • cementoblastoma

  • cemento-ossifying fibroma

• odontogenic cysts of inflammatory origin

  • radicular cyst

  • inflammatory collateral cysts

• odontogenic and non-odontogenic developmental cysts

  • dentigerous cyst

  • odontogenic keratocyst

  • lateral periodontal cyst and botryoid odontogenic cyst

  • gingival cysts

  • glandular odontogenic cyst

  • calcifying odontogenic cyst

  • orthokeratinized odontogenic cyst

  • nasopalatine duct cyst

• malignant maxillofacial bone and cartilage tumors

  • chondrosarcoma

  • mesenchymal chondrosarcoma

  • osteosarcoma

• benign maxillofacial bone and cartilage tumors

  • chondroma

  • osteoma

  • melanotic neuroectodermal tumor of infancy

  • chondroblastoma

  • chondromyxoid fibroma

  • osteoid osteoma

  • osteoblastoma

  • desmoplastic fibroma

• fibro-osseous and osteochondromatous lesions

  • ossifying fibroma

  • familial gigantiform cementoma

  • fibrous dysplasia

  • cemento-osseous dysplasia

  • osteochondroma

• giant cell lesions and simple bone cyst

  • central giant cell granuloma

  • peripheral giant cell granuloma

  • cherubism

  • aneurysmal bone cyst

  • simple bone cyst

• hematolymphoid tumors

  • solitary plasmacytoma of bone

Tumors of the ear

• tumors of the external auditory canal

  • squamous cell carcinoma

  • ceruminous adenocarcinoma

  • ceruminous adenoma

• tumors of the middle and inner ear

  • squamous cell carcinoma

  • aggressive papillary tumor

  • endolymphatic sac tumor

  • otosclerosis

  • cholesteatoma

  • vestibular schwannoma

  • meningioma

  • middle ear adenoma

Paraganglion tumors

• carotid body paraganglioma

• laryngeal paraganglioma

• middle ear paraganglioma

• vagal paraganglioma