Figure 1
Axial pre-contrast brain CT examination
A well circumscribed, homogenous fluid filled mass within the pineal gland with nodular calcification in the cyst wall.
Pineal cyst
SectionNeuroradiology
Case TypeClinical Cases
Authors
Koutsokosta E, Anastasiadou K, Voultsinou D, Papapostolou I, Doula D, Palladas P
CT and MRI Department, General Hospital ‘G.Papanikolaou’, Thessaloniki, Greece
Connected authors
18 years, male
Clinical History
An 18-year-old boy was referred to the radiology department because of headache.
Imaging Findings
An 18-year-old boy was referred to the radiology department for evaluation of headache.
A non-enhanced CT brain examination and a pre and post-contrast brain MRI examination were performed.
Brain CT examination revealed a well circumscribed, homogenous fluid filled lesion within the pineal gland with nodular calcification in the wall.
Brain MRI examination revealed a lesion in the area of pineal gland which was slightly hypodense on T1, hyperdense on T2 and did not attenuate fully on Flair. DWI demonstrated low signal intensity with increased ADC values. No restriction of diffusion was observed. After intravenous administration of gadopentetate dimeglumine the cystic lesion had a thin, smooth rim of enhancement of the cyst wall.
Findings were compatible with pineal cyst and atypical pineocytoma with cystic necrosis. We suggest a new MRI examination after 6 months, which showed the same findings with no change of size of the cystic lesion. The cystic appearance of the lesion with no restricted diffusion and the same size of it, after the new examination, were compatible with pineal cyst.
A non-enhanced CT brain examination and a pre and post-contrast brain MRI examination were performed.
Brain CT examination revealed a well circumscribed, homogenous fluid filled lesion within the pineal gland with nodular calcification in the wall.
Brain MRI examination revealed a lesion in the area of pineal gland which was slightly hypodense on T1, hyperdense on T2 and did not attenuate fully on Flair. DWI demonstrated low signal intensity with increased ADC values. No restriction of diffusion was observed. After intravenous administration of gadopentetate dimeglumine the cystic lesion had a thin, smooth rim of enhancement of the cyst wall.
Findings were compatible with pineal cyst and atypical pineocytoma with cystic necrosis. We suggest a new MRI examination after 6 months, which showed the same findings with no change of size of the cystic lesion. The cystic appearance of the lesion with no restricted diffusion and the same size of it, after the new examination, were compatible with pineal cyst.
Discussion
Pineal cysts are common lesions. They are seen in up to 10% of cases at routine imaging and they may be seen as many as 40% of autopsy specimens. Microscopically, benign pineal cysts exhibit three distinct layers. The outer layer consists of a thin layer of fibrous connective tissue. The middle layer is composed of pineal parenchyma with or without calcium and the inner layer is composed of finely fibrillar glial tissue which often contains haemosiderin deposits.
There are three theories about the origin of pineal cysts and cystic degeneration of the pineal gland: a) ischemic glial degeneration with or without haemorrhagic expansion, b) preexisting cysts that enlarge under hormone influence and c) enlargement of the embryonic pineal cavity.
Pineal cysts are almost always asymptomatic. Rarely, they produce symptoms, and these usually result from mass effect or haemorrhage. Compression of the midbrain tectum may produce Parinaud syndrome.
Hydrocephalus with signs and symptoms of raised intracranial pressure may be produced of aqueductal compression.
The diagnosis can be confirmed with CT and MRI images of the brain.
On non enhanced CT examination they can be appeared as unilocular well-circumscribed, homogenous fluid filled masses within the pineal gland behind the III ventricle. One fourth of them have a rim or nodular calcium in the cyst wall. Rim or nodular enhancement is also common.
On T1-weighted images they are only slightly hyperintense relative to the cerebrospinal fluid (CSF).
On T2-weighted images and proton density-weighted images they are hyperintense relative to CSF.
On diffusion–weighted images the pineal cyst demonstrates no restricted diffusion.
After intravenous administration of gadopentetate dimeglumine they can have a thin, smooth rim of enhancement of the cyst wall. Diffusion of contrast material into the cyst may cause more generalised enhancement if imaging is delayed.
The imaging features of atypical pineal cysts include irregular nodular enhancement and haemorrhage into a typical pineal cyst.
Differential diagnosis includes: i) pineocytoma, ii) other cysts in the quadrigeminal cistern that mimic pineal cyst like arachnoid cysts and epidermoid cysts. Pineocytoma is a benign pineal neoplasm. Usually it has solid components but there are cases where pineocytoma is only cystic and is impossible to distinguish the two lesions with imaging studies alone. They both grow extremely slowly and in some cases CT or MR-guided stereotactic biopsy are the only way to identify the right diagnosis. 80% of pineal cysts are smaller than 10 mm but cysts with diameter > 4, 5 cm have also been reported, so the size of the cyst is not pathognomonic for the diagnosis.
Additionally, there are some neoplasmatic lesions which may arise in the pineal region, such as germ cell tumours (germinoma, embryonal carcinoma, choriocarcinoma, teratoma), pineoblastoma and metastases. These tumours may contain cystic elements and several are highly malignant, maling follow up of a large or atypical cyst necessary.
There are three theories about the origin of pineal cysts and cystic degeneration of the pineal gland: a) ischemic glial degeneration with or without haemorrhagic expansion, b) preexisting cysts that enlarge under hormone influence and c) enlargement of the embryonic pineal cavity.
Pineal cysts are almost always asymptomatic. Rarely, they produce symptoms, and these usually result from mass effect or haemorrhage. Compression of the midbrain tectum may produce Parinaud syndrome.
Hydrocephalus with signs and symptoms of raised intracranial pressure may be produced of aqueductal compression.
The diagnosis can be confirmed with CT and MRI images of the brain.
On non enhanced CT examination they can be appeared as unilocular well-circumscribed, homogenous fluid filled masses within the pineal gland behind the III ventricle. One fourth of them have a rim or nodular calcium in the cyst wall. Rim or nodular enhancement is also common.
On T1-weighted images they are only slightly hyperintense relative to the cerebrospinal fluid (CSF).
On T2-weighted images and proton density-weighted images they are hyperintense relative to CSF.
On diffusion–weighted images the pineal cyst demonstrates no restricted diffusion.
After intravenous administration of gadopentetate dimeglumine they can have a thin, smooth rim of enhancement of the cyst wall. Diffusion of contrast material into the cyst may cause more generalised enhancement if imaging is delayed.
The imaging features of atypical pineal cysts include irregular nodular enhancement and haemorrhage into a typical pineal cyst.
Differential diagnosis includes: i) pineocytoma, ii) other cysts in the quadrigeminal cistern that mimic pineal cyst like arachnoid cysts and epidermoid cysts. Pineocytoma is a benign pineal neoplasm. Usually it has solid components but there are cases where pineocytoma is only cystic and is impossible to distinguish the two lesions with imaging studies alone. They both grow extremely slowly and in some cases CT or MR-guided stereotactic biopsy are the only way to identify the right diagnosis. 80% of pineal cysts are smaller than 10 mm but cysts with diameter > 4, 5 cm have also been reported, so the size of the cyst is not pathognomonic for the diagnosis.
Additionally, there are some neoplasmatic lesions which may arise in the pineal region, such as germ cell tumours (germinoma, embryonal carcinoma, choriocarcinoma, teratoma), pineoblastoma and metastases. These tumours may contain cystic elements and several are highly malignant, maling follow up of a large or atypical cyst necessary.
Differential Diagnosis List
Pineal cyst.
Final Diagnosis
Pineal cyst.
References
[1] Osborn AG, Preece MT (2006) Intracranial cysts: radiologic-pathologic correlation and imaging approach. Radiology 239:650-64 (PMID: 16714456)
[2] Steven DA, McGinn GJ, McClarty BM (1996) A choroid plexus papilloma arising from an incidental pineal cyst. AJNR 17:939-42 (PMID: 8733971)
[3] Fakhran S, Escott EJ (2008) Pineocytoma mimicking a pineal cyst on imaging: true diagnostic dilemma or a case of incomplete imaging?. AJNR Am J Neuroradiol 29:159-63 (PMID: 17925371)
[4] Arai Masayuki, Taguchi Motohiro (2003) Cystic lesions of the pineal region; report of two cases,. Japanese Journal of Clinical Radiology 48:775-779
[5] Osborn Diagnostic Imaging Brain I 7-26 to7-29, 6-88 to 6-91.
Case information
| URL: | https://eurorad.org/case/8414 |
| DOI: | 10.1594/EURORAD/CASE.8414 |
| ISSN: | 1563-4086 |
Figure 2
Axial pre-contrast brain MRI examination T1 sequence ( T1W1)
A hypodensity lesion within the pineal gland.
Figure 3
Post-contrast brain MRI examination T1 sequence (T1W1)
Axial post-contrast brain MRI scan T1 sequence (T1W1):
Smooth rim enhancement of the cystic wall of the pineal lesion.
Sagital post-contrast brain MRI scan T1 sequence (T1W1): Smooth rim of enhancement of the wall of the pineal lesion.
Coronal post-contrast brain MRI scan T1 sequence (T1W1): Smooth rim of enhancement of the wall of the pineal lesion.
Figure 4
Axial brain MRI examination T2 sequence (T2W2)
A hyperdensity lesion within the pineal gland.
Figure 5
Axial pre-contrast brain MRI scan FLAIR sequence
The cyst is not fully attenuated.
Axial pre-contrast brain CT examination
A well circumscribed, homogenous fluid filled mass within the pineal gland with nodular calcification in the cyst wall.
Axial pre-contrast brain MRI examination T1 sequence ( T1W1)
A hypodensity lesion within the pineal gland.
Post-contrast brain MRI examination T1 sequence (T1W1)
Axial post-contrast brain MRI scan T1 sequence (T1W1):
Smooth rim enhancement of the cystic wall of the pineal lesion.
Sagital post-contrast brain MRI scan T1 sequence (T1W1): Smooth rim of enhancement of the wall of the pineal lesion.
Coronal post-contrast brain MRI scan T1 sequence (T1W1): Smooth rim of enhancement of the wall of the pineal lesion.
Axial brain MRI examination T2 sequence (T2W2)
A hyperdensity lesion within the pineal gland.
Axial pre-contrast brain MRI scan FLAIR sequence
The cyst is not fully attenuated.
