Pleural mesothelioma with peritoneal involvement: Diagnosed on 18F-FDG positron emission tomography/computed tomography

Abstract

A 77‐year‐old‐male presented with a history of asbestos exposure and histologically proven malignant pleural mesothelioma. The patient was referred for 2‐[fluorine‐18] fluoro‐2‐deoxy‐d‐glucose positron emission tomography/ computed tomography (FDG PET/CT) for initial disease assessment which revealed extensive FDG avid irregular mass-like thickening involving right parietal and visceral pleura, leading to collapse of the underlying lung [Figure 1]. Along with that, FDG avid diffuse peritoneal and mesenteric thickening was noted [Figure 1]. Histopathology from the peritoneal thickening was not done due to poor patient compliance; however, due to extensive right pleural disease and increased FDG uptake in the peritoneum, the diagnosis of benign peritoneal involvement is less likely and of mesothelioma involvement is more likely. Malignant mesothelioma is a rare malignancy which originates from the cells lining the mesothelial surfaces, such as pleura, peritoneum, pericardium, and tunica vaginalis. The pleural form being the most common subtype,[1] however, peritoneal mesothelioma was the first to be described by Miller and Wynn (1908). The malignant peritoneal mesothelioma constitutes 12.5%–25% of all malignant mesotheliomas.[2] Mostly, it occurs in middle-aged men who commonly present with the complaints of abdominal pain or a feeling of fullness, abdominal distention or increasing abdominal girth, nausea, anorexia, and weight loss.[3] FDG PET for the diagnosis of malignant pleural malignancy (MPM) has been finding increasing use recently.[4] The principle is that the increased glucose metabolism of the tumor cells helps to identify malignancy at PET. The standardized uptake value (SUV), which is a semiquantitative measure of the metabolic activity of a lesion, is significantly increased in MPM than in benign pleural diseases such as inflammatory pleuritis and asbestos-related pleural thickening.[4,5] PET-CT provides both anatomic and metabolic information about a lesion. The sensitivity of FDG PET/CT is higher for detecting lymph node and distant metastases, thereby helps in staging.[6] Furthermore, higher SUV in FDG PET/CT is associated with poor prognosis.[7] FDG PET/CT also has higher accuracy for treatment response evaluation in malignant mesothelioma.[8] Our case also emphasizes that FDG PET/CT plays an important role in detecting the extent of the disease by detection of pleural as well as peritoneal lesion more so because it is a whole‐body scan which has an advantage of PET over CT alone. Thus, Pleural Mesothelioma with Peritoneal Involvement: Diagnosed on 18F-FDG Positron Emission Tomography/Computed Tomography