The World Health Organizatiοn (WHO) classification of head and neck tumours 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

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

• carcinomas

  • keratinising squamous cell carcinoma

  • non-keratinising 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 tumours

  • pleomorphic adenoma

• malignant soft tissue tumours

  • fibrosarcoma

  • undifferentiated pleomorphic sarcoma

  • leiomyosarcoma

  • rhabdomyosarcoma

  • angiosarcoma

  • malignant peripheral nerve sheath tumour

  • biphenotypic sinonasal sarcoma

  • synovial sarcoma

• borderline/low-grade malignant soft tissue tumours

  • desmoid-type fibromatosis

  • sinonasal glomangiopericytoma

  • solitary fibrous tumour

  • epithelioid haemangioendothelioma

• benign soft tissue tumours

  • leiomyoma

  • haemangioma

  • schwannoma

  • neurofibroma

• other tumours

  • meningioma

  • sinonasal ameloblastoma

  • chondromesenchymal hamartoma

• hematolymphoid tumours

  • extranodal NK/T-cell lymphoma

  • extraosseous plasmacytoma

• neuroectodermal/melanocytic tumours

  • Ewing sarcoma/primitive neuroectodermal tumours

  • olfactory neuroblastoma

  • mucosal melanoma

Tumours of the nasopharynx

• nasopharyngeal carcinoma

• nasopharyngeal papillary adenocarcinoma

• salivary gland tumours

  • adenoid cystic carcinoma

  • salivary gland anlage tumour

• benign and borderline lesions

  • hairy polyp

  • ectopic pituitary adenoma

  • craniopharyngioma

• soft tissue tumours

  • nasopharyngeal angiofibroma

• hematolymphoid tumours

• notochordal tumours

  • chordoma

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

• malignant surface epithelial tumours

  • 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 tumours

  • well-differentiated neuroendocrine carcinoma

  • moderately differentiated neuroendocrine carcinoma

  • poorly differentiated neuroendocrine carcinoma

• salivary gland tumours

  • adenoid cystic carcinoma

  • pleomorphic adenoma

  • oncocytic papillary cystadenoma

• soft tissue tumours

  • granular cell tumour

  • liposarcoma

  • inflammatory myofibroblastic tumour

• cartilage tumours

  • chondroma and chondrosarcoma

• hematolymphoid tumours

Tumours of the oral cavity and mobile tongue

• malignant surface epithelial tumours

  • 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

• tumours of uncertain histogenesis

  • congenital granular cell epulis

  • ectomesenchymal chondromyxoid tumour

• soft tissue and neural tumours

  • granular cell tumour

  • rhabdomyoma

  • lymphangioma

  • haemangioma

  • schwannoma and neurofibroma

  • Kaposi sarcoma

  • myofibroblastic sarcoma

• oral mucosal melanoma

• salivary type tumours

  • mucoepidermoid carcinoma

  • pleomorphic adenoma

• hematolymphoid tumours

  • CD30-positive T-cell lymphoproliferative disorder

  • plasmablastic lymphoma

  • Langerhans cell histiocytosis

  • extramedullary myeloid sarcoma

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

• squamous cell carcinoma

  • squamous cell carcinoma, HPV-positive

  • squamous cell carcinoma, HPV-negative

• salivary gland tumours

  • pleomorphic adenoma

  • adenoid cystic carcinoma

  • polymorphous adenocarcinoma

• hematolymphoid tumours

  • Hodgkin lymphoma

  • Burkitt lymphoma

  • follicular lymphoma

  • mantle cell lymphoma

  • T-lymphoblastic leukaemia/lymphoma

  • follicular dendritic cell sarcoma

Tumours and tumour-like lesions of the neck and lymph nodes

• tumours of unknown origin

  • carcinoma of unknown primary

  • Merkel cell carcinoma

  • heterotopia-associated carcinoma

• hematolymphoid tumours

• cysts and cyst-like lesions

  • branchial cleft cyst

  • thyroglossal duct cyst

  • ranula

  • dermoid and teratoid cysts

Tumours of salivary glands

• malignant tumours

  • 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 tumours

  • pleomorphic adenoma

  • myoepithelioma

  • basal cell adenoma

  • Warthin tumour

  • 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

  • haemangioma

  • lipoma/sialolipoma

  • nodular fasciitis

• hematolymphoid tumours

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

Odontogenic and maxillofacial bone tumours

• 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 tumours

  • ameloblastoma

    • ameloblastoma, unicystic type

    • ameloblastoma, extraosseous/peripheral type

    • metastasising ameloblastoma

  • squamous odontogenic tumour

  • calcifying epithelial odontogenic tumour

  • adenomatoid odontogenic tumour

• benign mixed epithelial and mesenchymal odontogenic tumours

  • ameloblastic fibroma

  • primordial odontogenic tumour

  • odontoma

  • dentinogenic ghost cell tumour

• benign mesenchymal odontogenic tumours

  • 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 tumours

  • chondrosarcoma

  • mesenchymal chondrosarcoma

  • osteosarcoma

• benign maxillofacial bone and cartilage tumours

  • chondroma

  • osteoma

  • melanotic neuroectodermal tumour 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 tumours

  • solitary plasmacytoma of bone

Tumours of the ear

• tumours of the external auditory canal

  • squamous cell carcinoma

  • ceruminous adenocarcinoma

  • ceruminous adenoma

• tumours of the middle and inner ear

  • squamous cell carcinoma

  • aggressive papillary tumour

  • endolymphatic sac tumour

  • otosclerosis

  • cholesteatoma

  • vestibular schwannoma

  • meningioma

  • middle ear adenoma

Paraganglion tumours

• carotid body paraganglioma

• laryngeal paraganglioma

• middle ear paraganglioma

• vagal paraganglioma