Objective To study the CT and MR imaging features of skull epidermoid cyst. Methods CT and MR findings of 4 cases of pathologically proved skull epidermoid cyst were analyzed and correlated with operative and pathologic reports.Results CT and MR appearances of skull epidermoid cyst were as follows:(1)crater-form or scalloping deossification with sclerotic border and fatty density focus was detected on CT.(2)The lesions were isointense to hypointense relative to normal white matter in T1-weighted image,prominent hyperintense in T_2-weighted image,mild to moderate hyperintense in diffusion-weighted imaging(DWI),and isointense to hypointense in apparent diffusion coefficient(ADC) map on MR.Proton MRS revealed lactate(Lac)peaks at 1.3 ppm and amino acids(AAs)at 0.9 ppm. (3)No enhancement was found in substance region of all tumors on both enhanced CT and enhanced MR examinations.Conclusion CT and MR appearances of skull epidermoid cyst have unique features which are very helpful in the diagnosis of skull epidermoid cyst.

Sarcomatoid carcinoma is a rare, malignant biphasic neoplasm with an epithelial and a spindle cell component. Primary sarcomatoid carcinomas arising from mandibular gingiva are known to be extremely rare, with only one case reported to date. Herein, we discuss the radiographic and computed tomographic appearances and pathological features of primary mandibular sarcomatoid carcinoma, which was confirmed by clinicopathology, in a 72-year-old man. In addition, we present a brief review of the relevant literature.
Aged ; Bone and Bones ; diagnostic imaging ; Carcinoma ; pathology ; Carcinoma, Small Cell ; pathology ; Carcinosarcoma ; pathology ; Gingiva ; pathology ; Gingival Neoplasms ; pathology ; Humans ; Male ; Mandibular Neoplasms ; pathology ; Sarcoma ; pathology ; Tomography, X-Ray Computed