Thin-walled cysts as a pathognomonic CT finding in cystic mesothelioma

Cystic mesothelioma is a rare disease that results in abdominal distention and poorly defined abdominal pain. Diagnosis has always been made by tissue biopsy rather than by radiologic studies.

Our experience with 7 patients with cystic mesothelioma includes 4 patients who had not had prior surgery before the performance of a high resolution CT scan. A special review of the radiology of these cases was performed in order to identify any pathognomonic signs of this disease.

In all patients who did not have a distortion of the radiologic images (as a result of surgical interventions) prior to the performance of a high resolution CT scan at our institution, a pathognomonic thin-wall cystic structure located within the gelatinous appearing mass was observed. These thin-walled cysts were of variable size and preferentially located within the greater omentum, pelvis and beneath the right hemidiaphragm.

Cystic mesothelioma can be diagnosed preoperatively by a high resolution abdominal and pelvic CT. The thin-walled cysts with great variation in size are located beneath the right hemidiaphragm, within the greater omentum and in the pelvis. No other disease with these radiologic findings has been identified.