LONG-TERM FOLLOW-UP OF MEDIASTINAL PERIVASCULAR EPITHELIOID CELL TUMOR

Abstract

SESSION TITLE: Lung Cancer 3 SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: 10/09/2018 01:15 PM - 02:15 PM INTRODUCTION: Perivascular Epithelioid Cell Tumors (PEComas) are rare mesenchymal tumors associated with tuberous sclerosis complex. The prognosis of PEComa are unpredictable. Due to the rarity of these tumors, mediastinal PEComa’s present a diagnostic & therapeutic challenge. Once identified, these patients require long-term follow-up due to uncertainty with treatment response. The purpose of this case is to demonstrate the response to treatment. CASE PRESENTATION: A 27 year old Indian male presents to the hospital in 2010 with a 1 month history of fever, left sided chest pain, dyspnea and cough. Past medical history was unremarkable. Surgical history consisted of excised occipital fibrolipoma many years ago. Family history was negative for malignancy or lung disease. Positive exam findings include shagreen patch on the left lateral neck, hypomelanotic ash leaf spot on the sternum and ungual fibroma. Chest X-ray revealed extensive infiltrate in the left lower lobe with CT chest confirming bilateral bullous emphysema and necrotizing pneumonia. It also detected 6.7 cm subcarinal mass. He subsequently underwent right thoracotomy on 3-23-2010, where a large mass was identified with a well-encapsulated overlying pleural envelope. H&E staining showed spindle cell neoplasm. Biopsy samples were immunoreactive and positive for actin, desmin, and HMB-45 and negative for S-100, CD34, kit (CD117), Melan-A, and h-caldesmon. Tumor necrosis factor was not tested. Diagnosis of PEComa was made based on immunoreactivity. Patient was also diagnosed with Tuberous Sclerosis complex due to constellation of physical findings. He declined genetic testing due to cost.Patient was started on Sirolimus for his PEComa in July 2010 and underwent serial CT scans at 3 month intervals. He has been followed closely for last 8 years and has tolerated Sirolimus well without any side effects. He has shown steady clinical and radiographic response to Sirolimus without any evidence of metastasis. His last CT Chest showed tumor size reduction to 1.9 cm in December 2017. He has been treated surgically for left spontaneous pneumothorax due to his bullous emphysema recently in December 2017 DISCUSSION: Treatment of PEComa with mTor inhibitors like Sirolimus, has been described with variable results. In this case, primary PEComa arising from the lung showed significant radiographic improvement in the tumor size. CONCLUSIONS: This case illustrates an example of a rare neoplasm associated with Tuberous Sclerosis Complex, which poses a diagnostic and therapeutic challenge. Sirolimus and other mTOR inhibitors show promise as potential treatment option for these tumors. Long term follow-up and prospective studies are needed for such neoplasms. Reference #1: Wagner AJ, Malinowska-Kolodziej I, Morgan JA, et al. Clinical Activity of mTOR Inhibition With Sirolimus in Malignant Perivascular Epithelioid Cell Tumors: Targeting the Pathogenic Activation of mTORC1 in Tumors. Journal of Clinical Oncology. 2010;28(5):835-840. https://doi.org/10.1200/JCO.2009.25.2981. DISCLOSURES: No relevant relationships by Riju Dasgupta, source=Web Response No relevant relationships by Asok Dasgupta, source=Web Response No relevant relationships by Patrick Elwood, source=Web Response No relevant relationships by Chelsea Leipold, source=Web Response No relevant relationships by Sivaraman Sivaswami, source=Web Response No relevant relationships by Paresh Timbadia, source=Web Response