Dermoid Cyst of the Prepontine Cistern and Meckel's Cave: Illustrative Case and Systematic Review

A dermoid cyst misdiagnosed as a lipoma due to atypical magnetic resonance images: a case report

Background

Dermoid cysts are well-known lesions that manifest as subcutaneous tumors around the lateral sides of the eyebrows in young patients. Computed tomography or magnetic resonance imaging (MRI) is often performed to confirm the diagnosis. On the other hand, a lipoma is usually a circular lesion, which is sometimes observed in the upper part of the face. The signals of both T1-weighted and T2-weighted images of MRI of a lipoma are, in general, relatively highly homogenous, and the signals decrease in fat-suppressed images. Therefore, differential diagnosis between a dermoid cyst and a lipoma is usually made with MRI, especially based on fat-suppressed images. Here, we present a case of misdiagnosis of a dermoid cyst as a lipoma because of atypical magnetic resonance images.

Case presentation

We report a case of a 24-year-old Japanese woman with a dermoid cyst around the lateral edge of the eyebrow. The cyst had been gradually increasing in size for the past 2 years. On MRI, it showed high internal signals on T1- and T2-weighted images. However, the signal intensity decreased homogeneously in the fat-suppressed T2-weighted images. The observed tumor had a yellowish appearance under the endoscope. On the basis of these findings, the lesion was considered a lipoma until it ruptured intraoperatively. The pathological diagnosis confirmed it to be a dermoid cyst.

Conclusion

Some dermoid cysts contain lipid-rich liquid, and these may be misdiagnosed as lipomas by MRI. When a tumor is located at a common site for a dermoid cyst, the MRI images should be validated carefully if it appears like a lipoma, and the differential diagnosis should be considered carefully.

Ruptured dermoid cyst in the Meckel's cave presenting with trigeminal neuralgia in a pediatric patient: a case report

Intracranial dermoid cysts are benign congenital slow growing masses. They account for less than 1% of all primary intracranial lesions. They can be asymptomatic and appear incidentally on brain images. However, there are some dermoid cysts that, depending on the location, can cause a variety of symptoms, especially if they compress vital structures. Rupture of intracranial dermoid cysts is relatively uncommon; the incidence is 0.18%. Dermoid cyst in children appears in the posterior fossa, while in adults is more common to find them in the sellar, temporal, and frontobasal region. The Meckel's cave is not a frequent location for these lesions and there are only a few cases in the adult population reported in the literature. We presented a 12-year-old patient with a dermoid cyst in the Meckel's cave who first presented with symptoms of a ruptured cyst but eventually evolved with a trigeminal neuralgia. We decided to do a transzygomatic approach and a middle fossa pealing to locate and excise the lesion. After surgery, the patient resolved the symptoms. Surgery is recommended in symptomatic lesions although surgical decision-making should consider the region where the cyst is located to achieve a safe, maximal resection without adding any further damage.

Rare Case of Giant Supratentorial Dermoid Cyst

BACKGROUND

Dermoid cysts are benign, congenital rare lesions, frequently occurring in or near the midline. Rare localizations and variable radiologic findings have been described but remain exceptional.

CASE DESCRIPTION

The authors present a rare case of a giant temporoparietal dermoid cyst in an adult female who was paucisymptomatic. No sign of rupture was identified, with a clinical presentation suggesting a slow-growing lesion. Gross total excision was performed with a favorable clinical and radiologic outcome.

CONCLUSIONS

Rare localizations previously published in the literature are discussed for dermoid cysts. To our best knowledge, this is the first giant dermoid cyst presenting with this localization.