Diagnosis of epidermoid tumor by computed tomography. Analysis and evaluation of findings

Dense cerebellopontine epidermoid cyst

A diffuse, bubblelike, high-density epidermoid cyst of the cerebellopontine angle is described as seen on CT scanning. The high density was attributed to high protein concentration of the cystic fluid due to a proliferative and exudative defense reaction to a "minor leak" of the lipidic material through the capsule, verified by Sudan black B stain. A description of the appearance of the tumor on computerized tomography, based on 42 cases of intracranial epidermoids reported in the literature, is discussed. To our knowledge this is the first morphological documentation of spontaneous leakage of cyst contents, and the second report in the English literature of a dense intracranial epidermoid.

Unusual CT-dense posterior fossa epidermoid cyst: case report

✓ A posterior fossa epidermoid cyst with high computerized tomographic attenuation is reported. The pathological and radiological features of this unusual case are presented.

Computed tomography of intracranial epidermoid tumours with special reference to atypical features

Intracranial intradural epidermoid tumours have been known to show characteristic CT features consisting of non-enhancing lucent lesions with sharply defined margins that are often irregular and scalloped. Since the epidermoid tumours are benign, potentially curable lesions, it should be also noted that they may occasionally show atypical CT features such as dense lesion, definite marginal enhancement following contrast medium injection, or tumour associated with large, heavy calcifications. Four such atypical cases are reported, and the literature is reviewed.

Intracranial epidermoid mimicking meningioma

A case of an epidermoid cyst in the frontal base which showed homogeneous high density in noncontrast computed tomography, simulating a meningioma with calcification, is reported. Operative findings and histological examination suggested that this high density was caused by spontaneous hemorrhage into the cyst.

Neuroradiological manifestations of suprasellar pituitary adenomas, meningiomas and craniopharyngiomas

The radiological manifestations of 16 pituitary adenomas, six meningiomas and 14 craniopharyngiomas were reviewed. The differential diagnosis of these tumors is possible with a few exceptions when skull radiography, CT, angiography and metrizamide cisternography are carefully evaluated. Prolonged injection angiography (PIA) is particularly important for demonstrating the contours of pituitary adenomas and meningiomas. Metrizamide cisternography is indicated when the tumor contours are obscure using PIA, or when the differential diagnosis is uncertain.

Parasellar epidermoid tumor presenting as painful ophthalmoplegia

In 1964, a 51-year-old man experienced a right abducens nerve palsy, which resolved spontaneously. In 1978, he developed painful ophthalmoplegia on the right with paresis of the right oculomotor and trigeminal nerves. Neuroradiographic evaluation was reported unremarkable, and the painful ophthalmoplegia was attributed to the Tolosa-Hunt syndrome. High-dose corticosteroids were administered with transient improvement of signs and symptoms. In 1979, cranial computerized tomography demonstrated a low-density lesion adjacent to the right cavernous sinus, which at operation proved to be an epidermoid tumor.

Intracranial intradural epidermoids and dermoids. Surgical results of 38 cases

This report covers 38 Cases of intradural dermoids (4 cases) and epidermoids (34 cases). In most cases the clinical course extended over several years. At the time of admission to the clinic only 9 patients had purely local symptoms; symptoms from adjacent areas were present in 15 cases and elevated intracranial pressure in 13. Of the 35 operated patients, 16 were able to work again, and 7 died after the operation. Best results are achieved in cases involving young patients, in cases where the tumor is situated in the cerebral hemisphere, and in cases where the tumor can be totally removed. In recent years advances in diagnostic, surgical and anaesthetic techniques have lowered the lethality rate. Computed tomography is especially useful for an early diagnosis.

Diagnosis by computerized tomography of intradural dermoid with spontaneous rupture of the cyst

Two cases of para- and suprasellar dermoid cysts are presented. The specific CT findings for this tumour are demonstrated: very low absorption values below minus 40 EMI units, variable densities in the cyst content, shell-like annular calcifications, and absent central enhancement effect. Spontaneous perforation of the cyst with dissemination of dermoid material into the CSF spaces is shown. The differential diagnosis from other low density lesions (epidermoid, cystic craniopharyngioma, arachnoid cyst) is discussed.

Primary intracranial epidermoid carcinoma. Case report

✓ A case is presented of primary intracranial epidermoid carcinoma in the right cerebellopontine angle which was visualized as a homogeneously enhanced mass on computerized tomography. At autopsy the malignant tissue was found to have invaded the brain stem.

Cranial computed tomography of epidermoid and congenital fatty tumors of maldevelopmental origin

The computed tomographic and clinical findings in 17 patients with fatty intracranial tumors and in 10 patients with epidermoid tumors, all of maldevelopmental origin, are presented. Fat was found in lipomas (the most frequent), dermoids, and teratomas. Differentiation between these tumors is discussed on the basis of density, calcification, location, and symptomatology.

Low attenuation lesions in the midline posterior fossa: differential diagnosis

A wide variety of cystic appearing or low attenuation lesions in the midline posterior fossa can so closely resemble one another as to render specific histologic diagnosis from CT scans alone fraught with error. Absorption coefficients often overlap and are too nonspecific to infer consistently accurate histologic diagnosis. It is virtually impossible to separate cystic from noncystic, benign from malignant, and neoplastic from non-neoplastic lesions by absorption coefficients alone.

A case of epidermoid of the fourth ventricle

The case of woman, aged 52, who had a fourth ventricular epidermoid, which eluded definite diagnosis for six years because of spontaneous remissions, is reported. Computed tomography may be misleading in such cases with spontaneous remission of symptoms because of the low electron density of the tumor which is not enhanced by intravenous contrast medium. Other diagnostic means such as ventriculography should not be neglected.

Preoperative diagnosis of a ruptured intracranial dermoid cyst by computerized tomography. Case report

A case of ruptured intracranaial dermoid cyst in the right middle fossa is reported. A definitive diagnosis of the lesion and the fact that it had ruptured was made possible by specific computerized tomographic findings. The findings were confirmed at surgery.

CT diagnosis of intracranial cystic abnormalities in children

The introduction of computed axial tomography has been of tremendous importance in the evaluation of intracranial pathology in children. The broad spectrum of cystic intracranial lesions of congenital, infectious, traumatic, vascular and neoplastic origin are discussed. Their CT findings, pathology and pathogenesis are emphasized.

CT scan and gas encephalography in diagnosis of arachnoid cyst and epidermoid cyst of Galen's cistern

The CAT scan is insufficient to make the differential diagnosis between an arachnoid cyst and an epidermoid cyst in the cistern of Galen. Gas encephalography is necessary. This procedure reveals arachnoid cysts of the commmunicating type, but is insufficient in distinguishing between an epidermoid cyst and a non-communicating arachnoid cyst. In this situation, histograms of the absorption values in each section of the lesion may be helpful for the diagnosis.

Limitations of computed tomography in the investigation of acoustic neuromas

Seventy percent of 80 surgically proven acoustic neuromas were visualized on preoperative computed tomography (CT) scans. Many more tumors were seen on contrast enhanced scans than on unenhanced scans (55 vs 25). No intracanalicular tumors and only one of 15 tumors less than 2 cm in size were visualized on CT scan. Most medium size tumors (2.0-3.0 cm) and all large tumors (greater than 3.0 cm) were visualized on CT scan when optimal technique was used. Positive CT scans often replace more invasive diagnostic studies in the investigation of acoustic neuromas. Negative scans do not rule out tumors as intracanalicular, and small tumors are usually not visualized with current techniques. If there is clinical suspicion of an acoustic neuroma, positive contrast posterior fossa cisternography should be done when the CT scan is negative.