Clinical Reasoning: An unusual case of auditory hallucinations in a middle-aged man

Symptomatic perianeursymal cyst development 20 years after endovascular treatment of a ruptured giant aneurysm: Case report and updated review

Perianeurysmal cysts are a rare and poorly understood finding in patients both with treated and untreated aneurysms. While the prior literature suggests that a minority of perianeurysmal cysts develop 1-4 years following endovascular aneurysm treatment, this updated review demonstrates that nearly half of perianeurysmal cysts were diagnosed following aneurysm coiling, with the other half diagnosed concurrently with an associated aneurysm prior to treatment. 64% of perianeurysmal cysts were surgically decompressed, with a 39% rate of recurrence requiring re-operation. We report a case of a 71-year-old woman who presented with vertigo and nausea and was found to have a 3.4 cm perianeurysmal cyst 20 years after initial endovascular coiling of a ruptured giant ophthalmic aneurysm. The cyst was treated with endoscopic fenestration followed by open fenestration upon recurrence. The case represents the longest latency from initial aneurysm treatment to cyst diagnosis reported in the literature and indicates that the diagnosis of perianeurysmal cyst should remain on the differential even decades after treatment. Based on a case discussion and updated literature review, this report highlights proposed etiologies of development and management strategies for a challenging lesion.

[Auditory phenomena as differential diagnostics to tinnitus]

INTRODUCTION

In the auditory system, subjective tinnitus is known as phantom perception. Humans also report illusionary misperceptions of real listening impressions and complex scene-like acoustic fantasies without external hearing stimulus. The exact pathophysiological relationships of the auditory phenomena are still unclear. Important comorbidities include hearing loss, brain disease and mental disorders.

METHODS

In a literature search in the PubMed database, publications were evaluated until March 2021 on the search terms tinnitus, palinacousis, pareidolia, synesthesia, aura, acoustic hallucination with regard to similarities and differences to subjective tinnitus.

RESULTS

Subjective tinnitus can occur together with other auditory phenomena in an individual. Diagnostically important is the relationship between hearing loss and tinnitus as well as between tinnitus and hearing loss in the corresponding frequency range. With hearing loss, other auditory phenomena may occur.

CONCLUSION

The occurrence of various auditory phenomena simultaneously in a person suggests an auditory perceptual continuum with common physiological processing structures. People with hearing loss should be asked about the various auditory phenomena. For all auditory phenomena, audiometric examination should be part of the diagnostic standard.

Intracranial perianeurysmal cysts: case series and review of the literature

BACKGROUND

Intracranial perianeurysmal cysts are a rare finding associated with cerebral aneurysms. Patients may present with symptoms secondary to mass effect from perianeurysmal cysts requiring drainage. These lesions can masquerade as neoplasms if dedicated vascular imaging is not performed, leading to misdiagnosis.

METHOD

A retrospective search of our database was done for intracranial aneurysms that have been treated between 1998 and 2020. A literature search was then performed on PubMed and Google Scholar with the search terms 'aneurysm', 'intracranial/intracerebral', 'cyst', and 'perianeurysmal cyst'. Patient demographics, aneurysms and cysts characteristics were then summarized as a table and in the discussion.

RESULTS

Three cases where intracranial aneurysm had associated perianeurysmal cysts were found in our database. Combined with the available literature a total of 19 cases of perianeurysmal cysts have thus far been reported since this entity was first described in 2002. A significant number of perianeurysmal cysts (5/19) required intervention. In 5/19 cases the patient presented with a perianeurysmal cyst without a history of subarachnoid hemorrhage. Of the 10 cases where aneurysm follow-up was reported there were 5 cases where there was aneurysm recurrence necessitating re-treatment.

CONCLUSION

Significant variability exists in the patient demographics, aneurysm and cyst characteristics of perianeurysmal cysts. This suggests that there is no single unified etiology and pathogenesis. These lesions are a rare finding and at present do not appear to carry diagnostic or prognostic significance. Management of perianeurysmal cysts is case-dependent and intervention should be considered when treating the related aneurysm, especially in patients with secondary symptoms.