Aims and objectives
Although intracranial epidermoid cyst is a remnant of ectodermal epithelial tissue from fetal development  while middle ear cholesteatoma is mostly acquired by the retraction of the tympanic membrane,
 they are histologically identical.
The cystic masses consist of a stratified squamous epithelial capsule filled with a waxy-appearing desquamated keratin debris and cholesterol crystals.
Differential diagnosis of both entities is challenging.
Epidermoid cyst is...
Methods and materials
Patients and study outline
Our prospective study was conducted between December 2009 and November 2013.
Patients with clinically suspected middle ear cholesteatoma and epidermoid cyst with no previous treatment underwent HASTE-DW,
T1 and T2 mapping MR examination prior to surgery.
Informed consent was signed by all patients.
The MRI findings were blinded to the surgeon.
Since the study aimed to validate our method,
it was important to investigate patients who definitely had...
2 patients with epidermoid cyst and 11 patients with middle ear cholesteatoma met the inclusion criteria and were recruited into our study.
10 patients were subsequently excluded due to MRI negativity.
In one of the patient with epidermoid cyst,
the lesion occupied the entire fourth ventricle extending into the cisterna magna.
Fig. 5 In the other patient,
the epidermoid was located in the cerebellopontine angle. Fig. 6
Among the patients with middle...
HASTE-DW is now widely used in the diagnosis of middle ear cholesteatoma due to its high sensitivity and specificity.
Restricted diffusion is one possible reason for the characteristic high signal in cholesteatoma and epidermoids on both DWI and HASTE-DWI sequences.
the diffusion of water molecules is less restricted in postsurgical conditions such as inflammated tissue,
granulation tissue or fibrous tissue resulting in a hypointense signal.
This enables differentiation.
1. Liu P,
Mr imaging of epidermoids at the cerebellopontine angle.
Magnetic resonance in medical sciences : MRMS : an official journal of Japan Society of Magnetic Resonance in Medicine 2003;2:109-115.
2. Olszewska E,
Etiopathogenesis of cholesteatoma.
Eur Arch Otorhinolaryngol...