Synchronous Diagnosis of Intradiploic Epidermoid Cyst and Anatomically Close Associated Chronic Epidural Hematoma.

Background: Intradiploic epidermoid cyst (IEC) concurrent with chronic epidural hematoma (CEDH) has never been reported in the literature. We report a unique case of IEC concurrent with anatomically close associated CEDH.

Methods: A 54-year-old man presented with a 1-week history of headache, confusion, and drowsiness. Computed tomography exposed large, extraaxial, mixed-density lesions with bone destruction and substantial mass effect in the left frontotemporal region. Magnetic resonance imaging revealed 2 adjacent extraaxial lesions. The frontal lesion was predominantly hyperintense on both T1-weighted imaging (T1WI) and T2-weighted imaging (T2WI), with an enhancement rim of the thickened dura mater. The frontotemporal lesion was mainly hyperintense on both TlWI and T2WI, with some areas of hypointensity on both T1WI and T2WI. No enhancement in the lesion was found. The patient underwent left frontotemporal craniotomy for resection of the lesion. At the time of the craniotomy, a copious amount of yellow liquid outflowed. After the bone flap was removed, an irregular tumor was found epidurally located and composed of fragile and laminated yellow materials. The tumor was totally removed. Histologic examination revealed an epidermoid cyst. Postoperative computed tomography showed mild bleeding in the operation area. His symptoms improved significantly after surgery, and he was discharged 1 week later. At 2 weeks' follow-up, the patient was well without neurologic deficits.

Conclusions: Intradiploic epidermoid cyst concurrent with chronic epidural hematoma is extremely rare. We present the first case of intradiploic epidermoid cyst concurrent with anatomically close associated chronic epidural hematoma.