Natural History and Management Options of Colloid Cysts

5 Natural History and Management Options of Colloid Cysts

Anthea H. O’Neill, Cristian Gragnaniello, and Leon T. Lai

Abstract

Colloid cysts are benign epithelial lined cysts and are generally located in the anterior third ventricle, in the region of the foramen of Monroe. Understanding the natural history of colloid cysts has been challenging, given their low incidence and the small number of cases in most reported series. Published data suggest that while the majority of colloid cysts will remain stable over time, and a small percentage will regress, there is a significant risk of progression necessitating operative intervention. The risk of acute deterioration and cyst-related mortality is low. The literature supports the need for surveillance of asymptomatic colloid cysts. Operative intervention is recommended for symptomatic patients, or those with cysts ≥ 10 mm, or those with hydrocephalus. When intervention is deemed appropriate, microsurgical resection via a transcallosal or transcortical approach should be considered.

Keywords: colloid cyst natural history intraventricular tumor microsurgery endoscopic surgery stereotactic aspiration

5.1 Introduction

Colloid cysts are benign epithelial lined cysts, and are generally located in the anterior third ventricle, in the region of the foramen of Monroe.1 They account for 0.5 to 2% of intracranial tumors¹^, ² correlating to an incidence of 3.2 per million population per year.²^, ³ The true prevalence is unknown but has been estimated at approximately 1 in 8,500 people.⁴ Typical age of presentation is between 20 and 50 years, with a possible familial predisposition,¹^, ⁵^, ⁶ and a slight male preponderance.⁷

Prior to the availability of modern neuroimaging, most colloid cysts encountered in the clinical setting were symptomatic. With increased use of neuroradiology, asymptomatic colloid cysts are readily discovered following cranial imaging for unrelated indications. Symptomatic colloid cysts present with headache, which may be postural, associated with nausea and vomiting, blurred vision, gait ataxia, and altered cognition.²^, ⁸^, ⁹ Incontinence, tinnitus, seizures, syncope, psychological manifestations, and dizziness have also been reported.¹^, ² Because of their location (Fig. 5.1), an enlarging cyst may cause obstructive hydrocephalus, resulting in acute rapid neurological deterioration and sudden death.

Fig. 5.1 Coronal section demonstrating a large colloid cyst in the roof of the third ventricle.

5.2 Selected Papers on the Natural History of Colloid Cysts

Beaumont TL, Limbrick DD Jr, Rich KM, Wippold FJ II, Dacey RG Jr. Natural history of colloid cysts of the third ventricle. J Neurosurg 2016;125(6):1420–1430

Pollock BE, Huston J III. Natural history of asymptomatic colloid cysts of the third ventricle. J Neurosurg 1999;91(3):364–369

5.3 Natural History of Colloid Cysts

Understanding the natural history of colloid cysts has been challenging given their low incidence and the small number of cases in most reported series. An overview of currently published case series regarding presenting clinical features and the natural history of colloid cysts is presented in Table 5.1.²^, ⁷^, ¹⁰^, ¹¹^, ¹²^, ¹³

Table 5.1 General demographics and clinical features of asymptomatic colloid cysts of the third ventricle

Studies	No. of patients	Mean age (y) (range)	Mean size (mm) (range)	Mean follow-up (mo) (range)	Radiologically stable, n (%, 95% CI)	Radiological progression, n (%, 95% CI)	Radiological regression, n (%, 95% CI)	Surgical intervention required, n (%; 95% CI)	Acute neurological deterioration, n (%; 95% CI)	Sudden death (%)	Cyst-related mortality, n (%; 95% CI)
Camacho et al¹⁰	24	52.0 (NR)	NR	19.3 (1.0–89.0)	NR	NR	NR	0	0	0	0
Kondziolka and Lunsford¹¹	6	NR	< 7.0^a	NR (36.0–84.0)	NR	NR	NR	0	0	0	0
Mathiesen et al⁷	7	47.9 (9.0–78.0)	15.9 (3.0–16.0)	22.0 (6.0–37.0)	3	4	0	4	0	0	0
Pollock and Huston¹²	58	57.0 (7.0–88.0)	8.0 (4.0–18.0)	79.0 (7.0–268.0)	32	2	0	2	1	0	1
Beaumont et al²	57	54.2 (NR)	7.0 (NR)	61.2 (6.0–276.0)	50	5	2	5	0	0	0
Roth et al¹³	13	35.0 (27.0–58.5)	6.9 (6.0–9.1)	33.0 (12.6–67.0)	13	0	0	0	0	0	0
	213	52.0^b (7.0–88.0)	7.0^b (3.0–18.0)	33.0^b (1.0–276.0)	98 (88.3; 95% CI 80.9–93.2)	11 (9.9; 95% CI 5.5–17.0)	2 (1.8; 95% CI 0.1–6.7)	11 (6.7, 95% CI 3.6–11.7)	1 (0.6, 95% CI –0.2–3.7)	0	1 (0.6, 95% CI –0.2–3.7)
Abbreviations: CI, confidence interval; mo, months; NR, not reported; y, years. ^aSize reported as less than the cutoff value. ^bMedian.

In general, colloid cysts may remain stable (88.3%), progress (9.9%), or regress in size (1.8%) during a median follow-up of 33.0 months (range: 1.0–276.0) from the time of diagnosis. Acute clinical deterioration occurred in 0.6% of cases. The risk of cyst-related mortality for asymptomatic colloid is estimated at 0.2% per year.

Most cysts less than 10 mm in diameter size do not cause hydrocephalus and are asymptomatic.¹ However, data indicate that most cysts will progress to some extent over time, as many patients with incidental colloid cysts nevertheless have some degree of hydrocephalus, indicating gradually enlarging cysts causing compromise of cerebrospinal fluid (CSF) flow during the patient’s lifetime.¹²^, ¹⁴ One-third of asymptomatic patients will have hydrocephalus at diagnosis. The rate of cyst progression necessitating surgical intervention was 6.7% (95% confidence interval [CI]: 3.6–11.7) during a median follow-up interval of 3 years following diagnosis. Approximately half of these patients required surgery due to development of symptoms related to their colloid cyst, and the other half due to growth of the cyst on follow-up radiological imaging. It is believed that younger patients with incidentally diagnosed colloid cysts are more likely to become symptomatic in the future than older patients with equivalent lesions.⁷^, ¹⁵

The most concerning presentation of a colloid cyst is an acute neurological deterioration, which has been reported in between 3 and 45% of patients, with an associated 5 to 38% risk of death.¹^, ²^, ⁴^, ⁹^, ¹⁶^, ¹⁷ In most cases, it is thought to be caused by rapid cyst enlargement leading to acute obstruction of the foramen of Monroe, and subsequent acute hydrocephalus and cerebral herniation (Fig. 5.2).⁴^, ¹²^, ¹⁴ However, alternative proposed mechanisms include disturbance of hypothalamic-mediated cardiovascular reflex control, venous infarction, spinal cord infarction, neurogenic pulmonary edema, and intracystic haemorrhage.¹^, ²^, ⁷^, ¹⁶^, ¹⁸^, ¹⁹^, ²⁰^, ²¹^, ²² Finally, several deaths have been precipitated by performing lumbar punctures in patients with colloid cysts.³^, ⁹

Fig. 5.2 An intraoperative image of a colloid cyst, (a) occluding the foramen of Monro and (b) following cyst removal.

In rare cases, colloid cysts have also been reported to spontaneously regress in size.2^, ⁶^, ²³ The mechanism by which the regression occurred is unclear; however, it has been postulated to be the result of asymptomatic cyst rupture.⁵^, ²⁴

5.4 Predicting the Risk of Sudden Death

There is considerable variation in the literature regarding the prognostic features of patients with colloid cysts who are at risk of sudden death. Acute hydrocephalus, with neurological deterioration and death, has been reported to be more likely in patients who are young, with ventriculomegaly, with cysts greater than 10 mm in diameter size, or T2 hyperintense lesions.²^, ⁷^, ¹²^, ¹⁴^, ¹⁶ It has been variably reported that both long-standing and acute onset of symptoms increase the likelihood of an acute deterioration.²^, ⁴^, ¹²^, ¹⁴ However, multiple studies have concluded that neither clinical nor neuroimaging features can be reliably used to estimate the risk of acute deterioration.⁴^, ¹⁶^, ²⁵

5.5 Selected Papers on the Treatment Outcomes of Colloid Cysts

Mathiesen T, Grane P, Lindquist C, von Holst H. High recurrence rate following aspiration of colloid cysts in the third ventricle. J Neurosurg 1993;78(5):748–752

Konovalov AN, Pitskhelauri DI, Shkarubo M, Buklina SB, Poddubskaya AA, Kolycheva M. Microsurgical treatment of colloid cysts of the third ventricle. World Neurosurg 2017;105:678–688

Samadian M, Ebrahimzadeh K, Maloumeh EN, et al. Colloid cyst of the third ventricle: long-term results of endoscopic management in a series of 112 cases. World Neurosurg 2018;111:e440–e448

5.6 Treatment Options

Management options for colloid cysts include observation or surgery. Asymptomatic colloid cysts can be conservatively managed with serial neuroimaging to assess for radiological progression.²^, ⁵^, ¹²^, ¹⁷ However, prompt neurosurgical intervention is indicated should the patient develop symptoms, when the cyst enlarges, or when CSF flow is compromised. Prevention of sudden death is not a surgical indication in asymptomatic patients with small cysts and no hydrocephalus. Lumbar puncture should be avoided in patients with colloid cysts prior to definitive management or ventriculoperitoneal shunt (VPS) insertion due to the risk of herniation.

In patients with acute hydrocephalus, immediate CSF diversion strategies with bilateral external ventricular drains or a VPS may be considered. The rationale for definitive surgery is to restore CSF drainage. In general, the entire cyst capsule should be removed to prevent recurrence.²⁶ Direct operative options include stereotactic cyst aspiration, endoscopic cyst removal, and microsurgical resection (transcallosal or transcortical). An overview of the outcomes of the available operative treatment options published between 1974 and 2020 is presented in Table 5.2.⁷^, ⁹^, ¹⁰^, ¹¹^, ¹³^, ²²^, ²⁶^, ²⁷^, ²⁸^, ²⁹^, ³⁰^, ³¹^, ³²^, ³³^, ³⁴^, ³⁵^, ³⁶^, ³⁷^, ³⁸^,