Pseudo-tumor mimicking indwelling pleural catheter tract metastasis in mesothelioma

Patients with malignant mesothelioma are known to be at risk of developing needle tract metastasis from seeding of malignant cells at the pleural intervention site. Histologic confirmation of needle tract metastases is seldom sought. The diagnosis and management (often radiotherapy) are almost always based on clinical judgment of new subcutaneous lesions at prior pleural puncture sites in mesothelioma patients. We report 2 patients with mesothelioma who developed new subcutaneous nodules at their indwelling pleural catheter insertion site, mimicking tract metastases. Biopsies of both lesions revealed benign etiologies and both resolved without requiring irradiation. These cases remind clinicians that new subcutaneous lesions can be benign even when arising at pleural puncture sites of malignant pleural mesothelioma patients. Percutaneous biopsy can clarify the diagnosis in suitable cases.