A Case of Dorsal Midbrain Syndrome in a Patient with Brain Metastases from Small Cell Lung Cancer

Background

Dorsal midbrain (Parinaud) syndrome is a neuro-ophthalmic syndrome caused by injury to or compression of the dorsal midbrain–especially the pretectal region, posterior commissure, and vertical gaze centers [1], [3]. This condition was first described by the French ophthalmologist Henri Parinaud in the late 19th century [1]. He reported a series of cases with disturbances of associated eye movements and vertical gaze paralysis and attributed the condition to lesions of the quadrigeminal (tectal) region [1]. The syndrome is also known as Sylvian aqueduct syndrome, dorsal midbrain syndrome, pretectal syndrome, and Koerber-Salus-Elschnig syndrome [1], [2].

Clinically, Parinaudʼs syndrome is characterized by a typical triad: limitation of upgaze (often with a downward gaze preference), convergence-retraction nystagmus on attempted upgaze, and pupillary light–near dissociation (poor light reaction with preserved near response) [1], [2], [3]. Lid retraction (Collier sign) is common [1], [2] ([Fig. 1]). Additional findings may include skew deviation, impaired convergence or accommodation, and occasionally downgaze limitation; vertical saccades are usually more affected than smooth pursuit due to disruption of fibers crossing the posterior commissure [3], [4].

Fig. 1 Typical signs of Dorsal Midbrain Syndrome and their frequency [1], [2].

Pathophysiologically, mass effect or intrinsic lesions interrupt the vertical saccade network–including the rostral interstitial nucleus of the medial longitudinal fasciculus–and pretectal pupillary pathways, explaining vertical gaze paresis, paradoxical convergence-retraction movements, and pupillary abnormalities [3], [4]. Obstructive hydrocephalus can exacerbate signs via compression of the tectal plate [1], [3].

Etiologies vary with age. In children and young adults, pineal-region tumors and tectal gliomas predominate [1], [2], [3]. In adults, ischemic or hemorrhagic midbrain strokes, demyelinating disease, compressive lesions (pineal or thalamic masses), obstructive hydrocephalus (e.g., aqueductal stenosis or shunt malfunction), arteriovenous malformations, inflammatory/infectious processes, trauma, and metastatic disease are reported causes [1] – [4]. Thalamic or pineal metastases can produce the syndrome by deforming the dorsal midbrain, as in the present case [1], [3], [4].

Recognition of this pattern should prompt urgent neuroimaging to identify reversible compression, ventricular enlargement, or intrinsic brainstem disease and to guide neurosurgical, oncologic, and medical management [1], [2], [3]. Partial improvement is often possible after treatment of the underlying process and relief of dorsal midbrain compression [1], [3].

Publication History

Received: 02 November 2025

Accepted: 19 November 2025

Article published online:
21 January 2026

• References

• 1 Feroze KB, Arain AM. Parinaud Syndrome. In: StatPearls [Internet] Treasure Island FL: StatPearls Publishing; 2023
• 2 Kini A. Parinaud Syndrome. EyeWiki [Internet]. American Academy of Ophthalmology. Accessed 08.12.2025 at: https://eyewiki.org/Parinaud_Syndrome
• 3 Prakash E, Kuht HJ, Harieaswar S. et al. Dorsal midbrain (Parinaud) syndrome. Pract Neurol 2021; 21: 550-551
• 4 Ortiz JF, Eissa-Garces A, Ruxmohan S. et al. Understanding Parinaudʼs Syndrome. Brain Sci 2021; 11: 1469
• 5 Shields M, Sinkar S, Chan W. et al. Parinaud syndrome: a 25-year (1991–2016) review of 40 consecutive adult cases. Acta Ophthalmol 2017; 95: e792-e793
• 6 Le Rhun E, Guckenberger M, Smits M. et al. EANO–ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up of patients with brain metastasis from solid tumours. Ann Oncol 2021; 32: 1332-1347