Vol.97 No.11
contentsPRACTICA OTO-RHINO-LARYNGOLOGICA
Vol. 97 No.11 November 2004
A
Case of Large Preauricular Epidermoid Cyst
Expanded into the Skull Base
Masayuki
Kabeya, Toshiyuki Fujisaki, Katsuro Sato,
Hajime Umezu and Sugata Takahashi
(Niigata University Faculty of Medicine)
Masahiro Kawana
(Kawana Ear, Nose and Throat Clinic, Niigata)
The patient was a 73-year-old male, complaining of progressive right otalgia and right facial palsy. A radical mastoidectomy on the right ear was performed, and the histopathological diagnosis was only granulous tissue. A small subcutaneous mass at the right preauricle appeared just after the operation, and an open biopsy was performed. The histopathological diagnosis was epidermoid cyst.
MRI showed a high intensity area from the right preauricle to around the medial pterygoid muscle. The symptoms were not improved by the administration of antibiotics and drainage. CT and MRI after about two months revealed that the epidermoid cyst and its infection had expanded from the infratemporal fossa to the pterygopalatine
fossa, but they were not detected as an apparent invading lesion of the skull base, so surgical treatment was selected. Although skull base surgery was performed, the cyst and its infection could not be extirpated completely, because they had expanded deeply into the skull base beyond the
clivus, against preoperative assessment. Disturbances of the central nervous system appeared and gradually increased. Finally, the patient died of respiratory failure.
We treated a rare case of preauricular epidermoid cyst invading the skull base. It was considered that the lesion was possibly more enlarged than was detected in the CT and MRI findings, due to the skull base infection.
Key words : epidermoid cyst, skull base, infection