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The clivus is a midline bone structure formed by the basisphenoid and basiocciput, forming part of the skull base posterior to the sphenoid sinus and anterior to the brainstem.

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Lesions of the clivus can arise from bone, adjacent structures, or notochordal remnants and include a wide range of benign and malignant conditions.

![Illustration of the Clival Classification and its relationship to the nasal cavity, sphenoid sinus and sella turcica. Each segment of the clivus is associated with specific cranial nerves and vasculature and therefore respective tumor involvement and risk of surgery to these structures

Rao D, Stein R, Jenson M, Patel J, Fiester P. Imaging Review of the Endoscopic Operative Corridor for Clivus Lesions. Current Problems in Diagnostic Radiology. 2023;52(1):66-76. doi:10.1067/j.cpradiol.2022.07.005](attachment:1429f2b8-43d7-4f49-b156-cb423244fdfe:1-s2.0-S0363018822001062-gr10.jpg)

Illustration of the Clival Classification and its relationship to the nasal cavity, sphenoid sinus and sella turcica. Each segment of the clivus is associated with specific cranial nerves and vasculature and therefore respective tumor involvement and risk of surgery to these structures

Classification

A. Congenital / Developmental

Lesion	Characteristics
‣	Benign notochordal remnant; intradural, non-enhancing
Benign notochordal cell tumor (BNCT)	Intraosseous, benign, midline vertebral lesion; stable on follow-up

B. Neoplastic

Lesion	Key Features
Chordoma	Malignant, destructive midline tumor from notochord
Chondrosarcoma	Off-midline, lytic lesion; often involves petroclival synchondrosis
Metastases	Variable; common in adults; multiple, destructive
Multiple myeloma / Plasmacytoma	Lytic, expansile lesion; “punched-out” appearance
Lymphoma	Soft tissue mass; minimal bone destruction, homogeneous enhancement
Pituitary macroadenoma (invasive)	Can extend inferiorly to clivus from sella
‣	Can invade clivus via direct extension from nasopharynx

C. Infectious / Inflammatory

Lesion	Features
Clival osteomyelitis	Often secondary to skull base infection (e.g., malignant otitis externa); marrow edema, enhancement
Tuberculous osteitis	Destructive lesion with soft tissue abscess and clival involvement

Clinical Features

Headache, cranial neuropathies (CN VI most common)
Diplopia, facial numbness, dysphagia (if large)
Signs of brainstem compression in large lesions
Recurrent sinusitis or nasal obstruction if adjacent invasion

Radiology

Characteristic Imaging Appearances