Katsuya Kato MD, Presenter: Nothing to Disclose

Fumikazu Sakai MD, PhD, Abstract Co-Author: Research Consultant, Bayer AG Research Consultant, F. Hoffmann-La Roche Ltd Research Consultant, Pfizer Inc

Yasuyuki Kurihara MD, Abstract Co-Author: Nothing to Disclose

Hirotaro Miura, Abstract Co-Author: Nothing to Disclose

Kouki Inai, Abstract Co-Author: Nothing to Disclose

Since primary pericardial mesothelioma (PPM) is an extremely rare condition, there is no radiologic study focusing on CT manifestations of PPM based on a large patient group. The aim of the present study is to characterize CT features of 17 cases with PPM.

We collected clinical, imaging, and pathological data of 20 cases of pericardial mesothelioma from 18 medical institutes in Japan. The data collection and study were supported by a research grant for the exploration of asbestos-related malignant tumor by the Ministry of Environment Japan. Clinico-radiologic-pathologic (CRP) diagnosis was performed by the consensus of the expert team (3 radiologists, 5 physicians, and 3 pathologists) in order to verify the eligibility of the diagnosis. We retrospectively analyzed imaging findings in cases with CRP agreement with PPM in order to characterize imaging features. Imaging protocols varied due to the retrospective nature of the study. Images were interpreted by the consensus of 3 experienced diagnostic radiologists.

We finally determined 17 cases of PPM on the basis of the CRP assessment of this original study group. Histological sub-classification was as follows: 13 epithelial, 2 biphasic, each of sarcomatoid and desmoplastic type. The imaging findings of the pericardium in 17 cases were as follows: no thickening, 4 cases (24%); mild thickening, 3 (18%); irregular thickening, 6 (35%); and mass formation, 4 (24%), thus, approximately 40% of the cases showed no or mild thickening and were not indicative of malignant nature. Two cases with mass formation mimicked mediastinal tumor. Pericardial thickness ranged from 0 cm to 7.2 cm (median, 1.2 cm). Pericardial effusion was observed in 13 of the 17 cases (76%); Pleural effusion was detected in 12(70%), pleural effusion on both sides, 8; right side, 2; and left side, 2. Seven patients (41%) showed mediastinal lymph node swelling greater than 10 mm in minimum diameter. Pleural plaque was found in 4 cases.

The imaging findings of PPM had a considerably wide spectrum and included not only pericardial masses but also simple pericardial effusion and mediastinal mass formation. It is very important to know the imaging spectrum in order to make a precise diagnosis of PPM.

CT findings of primary pericardial mesothelioma have a considerably wide spectrum, ranging from pericardial effusion to mediastinal mass formation.

Kato, K, Sakai, F, Kurihara, Y, Miura, H, Inai, K, CT Findings of 17 Cases of Primary Pericardial Mesothelioma.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11005850.html