Irresistible Laughter—A Rare Presentation of Intracranial Tumor: Irony of Neurocircuitry

Pseudobulbar affect (PBA) is defined as episodes of unprovoked uncontrollable laughter or crying not relatable to an emotional or environmental stimulus. PBA has been associated with various neurological diseases, drugs, movement disorders, stroke, posttraumatic brain injury, and intracranial lesions including cerebellopontine angle (CPA) tumors.[1]

A 29-year-old female presented with holo-cranial headaches and outbursts of uncontrolled laughs. Magnetic resonance imaging findings were suggestive of a 5.5 × 4.9 × 3.7 cm solid and cystic lesion in the right CPA compressing on the brainstem ([Fig. 1A]). Preoperative investigations were normal. A standard anesthetic technique for intraoperative neuromonitoring was used to facilitate electromyography of lower cranial nerves. Through a right frontotemporoorbitozygomatic craniotomy a yellowish-grey suckable tumor was seen between maxillary and mandibular divisions of cranial nerve V. Posterior fossa was entered and gross total excision of tumor extending to ventral part of brainstem was done ([Fig. 1B]). Histopathological examination of the resected tumor confirmed the trigeminal schwannoma. In the postoperative period, there was complete resolution of her psychiatric symptoms.

Fig. 1 (A) MRI with contrast showed a dumbbell-shaped extra-axial mass in the middle and posterior cranial fossa extending from the right cerebellopontine angle having cystic and hemorrhagic components. (B) NCCT head in the axial cut in the immediate postoperative period. MRI, magnetic resonance imaging; NCCT, noncontrast computed tomography.

Large intracranial lesions are thought to be responsible for the “release phenomenon” causing loss of control of the lower brainstem from the higher centers manifesting as psychiatric mimics.[2] Why not all patients have PBA remains elusive?[3] Not one particular area has been ascribed to the presentation, but various areas postulated to be involved are the periaqueductal region, and lateral pons with anatomical relations to the frontal, basal temporal, hypothalamus, basal ganglia, thalamus, cerebellum, and upper cervical spinal cord. Awareness of such odd presentations can help in prompt management, avoiding unwanted consultations, and additional preoperative anxiolytics, considering it a manifestation of higher levels of anxiety.

Thus, behind this reversible psychiatric presentation, there may be a large intracranial pathology requiring early management by tumor resection. Neuroanesthesiologists should be well versed in this rare exposition that mimics psychiatric symptomatology.

Conflict of Interest

None declared.

Patients' Consent

Patient consent was obtained for the publication of clinical information and images to enhance medical knowledge.

Authors' Contributions

K.K. helped review the literature and prepare the manuscript. N.B.P. helped review and approve the final version of the manuscript. S.M. helped design, review the literature, and prepare the manuscript. T.R. helped review and approve the final manuscript.

• References

• 1 Wortzel HS, Oster TJ, Anderson CA, Arciniegas DB. Pathological laughing and crying : epidemiology, pathophysiology and treatment. CNS Drugs 2008; 22 (07) 531-545
• 2 Wild B, Rodden FA, Grodd W, Ruch W. Neural correlates of laughter and humour. Brain 2003; 126 (Pt 10): 2121-2138
• 3 Gosal JS, Pandey S, Das KK. et al. Pathologic laughter as an early and unusual presenting symptom of petroclival meningioma: a case report and review of the literature. World Neurosurg 2019; 123: 161-164

Publication History

Article published online:
27 May 2024