Unusual Contiguous Soft Tissue Spread of Advanced Malignant Mesothelioma Detected by FDG PET/CT

Abstract

Malignant pleural mesothelioma (MPM) is a tumor of mesodermal origin that arises from the serosa of the pleura, peritoneum, pericardium or tunica vaginalis. MPM is well known to have a poor prognosis with a median survival time of 12 months. Accurate diagnosis, staging and restaging of MPM are crucial with [18F] flurodeoxy-D-glucose positron emission tomography (FDG PET/CT) playing an increasingly important role. Here we report a case of MPM with unusual contiguous soft tissue spread of the tumor along the dermal and fascial planes characterized by PET/CT. Given that the loco-regional tumor in the thorax was under control on PET/CT, the death of the patient was most likely associated with physiologic or metabolic causes associated with an extra-thoracic tumor.

Extensive Skeletal Muscle Metastases in Malignant Pleural Mesothelioma Detected by FDG PET/CT

“…Not many but several MPM cases with distant muscle metastases have been reported in the literature. 4 5 6 11 12 13 14 15 16 17 It was also noted that the most common histological type of tumor in those cases was epithelioid MPM as observed in our patient.…”

“…Multiple skeletal muscle metastases from MPM detected by FDG PET/CT was first reported by Aukema et al 12 FDG PET/CT was highlighted to be a superior and more effective imaging modality than CT alone in the evaluation of distant metastatic disease of MPM. 2 3 6 12 In the presented case, in addition to local recurrence and contralateral pleural metastases, PET/CT demonstrated extensive skeletal muscle metastases not suspected before, but there were no morphologic abnormalities on diagnostic CT corresponding to the hypermetabolic muscle lesions. As a result, FDG PET/CT provided more accurate restaging of our case with MPM.…”

“…FDG PET/CT imaging has been increasingly used for presurgical characterization and staging at presentation, for evaluation of response to treatment, and restaging during follow-up of patients with MPM. 6 7 8 Since FDG is a glucose analog, increased glucose use by malignant cells leads to high FDG uptake. Functional PET data, that is, increased FDG uptakes in malignant cells, along with anatomic CT data make FDG PET/CT a very useful and valuable imaging modality in most of malignant diseases.…”

“…Fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) has been increasingly used for the presurgical characterization and staging, evaluation of the response to treatment, accurate detection of distant metastases, assessing recurrence, and selecting the site for tissue biopsy of MPM. 6 7 8 …”

Comparison of the role of 18F-fluorodeoxyglucose PET/computed tomography and 68Ga-labeled FAP inhibitor-04 PET/CT in patients with malignant mesothelioma

“…MPerM is a very rare type of mesothelioma and TNM-8 and RECIST 1.1 criteria are used for staging and evaluation of response to treatment [8]. A limited number of cases have been reported in the literature with the diagnosis of MPerM, and distant organ metastases have been reported with 18 F-FDG PET/CT, CT and MRI in some of the cases [51][52][53][54]. In our study, there was one patient diagnosed with MPerM and although 18 F-FDG PET/ CT was successful in demonstrating locally and locally advanced disease, 68 Ga-FAPI-04 PET/CT was superior in detecting distant organ metastases.…”