When magnetic resonance imaging is needed: malignant pleural mesothelioma with transdiaphragmatic infiltration and localized appearance: a case report

Malignant pleural mesothelioma (MPM) most commonly presents with diffuse growth pattern and wide-spread infiltration of the pleural surface. In rare cases, also a localized form with a circumscribed pleural tumor mass has been identified. We report a case of MPM presenting with an atypical, radiologically localized appearance which was later proven to be a disseminated disease. After staging by positron-emission computed tomography (PET-CT), magnetic resonance imaging (MRI) was primarily used for planning the surgical resection. To date, no clinical evidence is available on the role of MRI for preoperative planning of the surgical approach. In a 58-year-old woman, CT revealed a solitary tumor bulk on the left diaphragm and transdiaphragmatic infiltration. Although CT in general is the method of choice to assess the tumor extent, this case clearly highlights the value of contrast MRI for assessing the diaphragmatic and soft tissue infiltration. Surgical resection was preformed and the intraoperative examination and frozen section revealed a disseminated pleural spread, corresponding to a diffuse pleural mesothelioma. The patient made an uneventful recovery and the radiological follow-up 1 year after surgery showed no signs of relapse. This case demonstrates that diffuse pleural mesothelioma may mimic imaging-wise a localized variant and highlights the importance of thorough preoperative assessment using MRI and intraoperative examination of the pleural cavity in these patients.