Tectal Plate Lipoma

Case History: We report the case of a rare lipoma in the quadrigeminal cistern in a 37-year-old female presenting with headache. She was referred to our diagnostic center by a local physician. Neurological and systemic examination were normal.

Blood analysis was within normal limits and EEG did not show abnormal discharges. Cranial NECT revealed a mass (10 x 7 mm in size) in the quadrigeminal plate cistern which had very sharply demarcated homogeneous low fatty density indicative of a lipoma (Figure 1).

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Figure 1. Axial, coronal and sagittal NECT image shows a small well-defined ovoid hypodense lesion having fat attenuation (- 74 to 96 HU) at quadrigeminal plate cistern.

Diagnosis: Quadrigeminal plate cistern lipoma/tectal plate lipoma

Discussion

• Intracranial lipomas are rare, slow-growing, benign congenital lesions accounting for 0.1-0.5 percent of all primary brain tumors and are usually detected as incidental findings.¹
• Lipoma in the quadrigeminal region has previously been reported as lipoma in the quadrigeminal cistern, the quadrigeminal plate, the ambient cistern, the superior vermis or the superior medullary velum^.1
• Lipomas of the quadrigeminal plate/ambient cistern produce symptoms in 20 percent of patients.³ We reported a patient with incidental lipoma of the quadrigeminal region.
• Diagnosis of quadrigeminal cistern lipoma is always certain on imaging, and therefore histopathological confirmation is never practically required.
• The differential diagnoses of lipomas in the quadrigeminal cistern include: arachnoid cysts, tectal plate cyst, tectal masses (gliomas), supracerebellar abscess, dermoid and epidermoid cysts, ruptured P4 segment aneurysm of the posterior cerebral artery and, rarely, pineal region mass.^4,5 The lipoma can be differentiated with other negative attenuation value lesions (epidermoid or dermoid tumors) that two tumors will demonstrate heterogeneous attenuation values.⁶
• Treatment of intracranial lipomas very rarely requires a direct surgical approach, because these tumors rarely reach a size sufficient to cause a mass effect or intracranial hypertension.¹

Learning Points

• Quadrigeminal plate cistern lipoma is rare.
• They are usually asymptomatic, but may cause significant symptoms of mass effect.
• Diagnosis of quadrigeminal cistern lipoma is always definitive on imaging, and therefore

histopathological confirmation is practically never required.

References
1. Nikaido Y, Imanishi M, Monobe T. Lipoma in the quadrigeminal cistern – case report. Neurol Med Chir (Tokyo). 1995;35:175–178.
2. Yilmaz N, Unal O, Kiymaz N, Yilmaz C, Etlik O. Intracranial lipomas--a clinical study. Clin Neurol Neurosurg. 2006;108:363-368.
3. Ono J, Ikeda T, Imai K, et al. Intracranial lipoma of the quadrigeminal region associated with complex partial seizures. Pediatr Radiol. 1998;28:729–731.
4. Nikaido Y, Imanishi M, Monobe T. Lipoma in the quadrigeminal cistern-case report. Neurol Med Chir (Tokyo). 1995;35:175-178.
5. Ogbole G, Kazaure I, Anas I. Quadrigeminal plate cistern lipoma. BMJ Case Rep. 2009;2009.
6. Kazner E, Stochdorph O, Wende S, Grumme T. Intracranial lipoma. Diagnostic and therapeutic considerations. J Neurosurg. 1980;52:234-245.