Solitary schwannoma of the gallbladder: A case report and literature review

Schwannomas occurring in the gallbladder are extremely rare.Preoperative diagnosis of gallbladder schwannomas appears to be very difficult because they are normally asymptomatic and are often found incidentally.Until now,only five cases have been reported in the literature.To our knowledge,the contrastenhanced ultrasound(CEUS)features of gallbladder schwannomas have not been reported before in other studies.We treated a 55-year-old male patient with gallbladder schwannoma in China.He had no symptoms,and the lesion was incidentally found by conventional ultrasound(US)when performing a health examination.The patient had normal liver function;moreover,serum carcinoembryonic antigen and alphafetoprotein were within the normal ranges.The lesionshowed no blood flow signals on color Doppler US,and the wall beneath the lesion was intact on CEUS.The lesion was believed to be a benign entity;in addition,gallbladder adenomyomatosis was suspected.A laparoscopic cholecystectomy was performed to remove the mass.Pathological examination revealed that the tumor was mainly composed of spindle-shaped cells;neither atypical cells nor signs of malignancy were found.Immunohistochemical staining showed a strong positive S-100 protein reaction.Vimentin and CD56staining were also positive,whereas CD34 and CD117were negative.Finally,the lesion was diagnosed as schwannoma.Herein,we report the case;the associated literature is also reviewed.