THYMIC CANCER WITH ADRENAL METASTASIS: A RARE PRESENTATION

Abstract

SESSION TITLE: Medical Student/Resident Disorders of the Mediastinum Posters SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: October 18-21, 2020 INTRODUCTION: Thymic tumors are rare invasive neoplasms and account for 0.2% to 1.5% of all neoplasms. Among them, thymic carcinomas are the most aggressive variant that represents approximately0.06% of all malignancies. Lung involvement is very common whereas extra-thoracic metastasis is rare. We describe a case of thymic cancer with adrenal metastasis which is a very rare presentation. This case highlights the various presentations of such a rare tumor which can often be missed due to the paucity of knowledge of this malignancy due to low incidence. CASE PRESENTATION: A 40-year-old male arrived at the hospital with a chief complaint of dull aching chest pain and back pain for one month. He also endorsed weight loss, night sweats, and weakness. He denied smoking, travel, or remote history of TB. Initial vitals, physical examination, and labs were unremarkable. He had a chest Xray which showed an 8 cm lobulated anterior mediastinal mass. Chest tomography (CT) showed large anterior mediastinal mass 7 x13 cm, enlarged mediastinal lymph nodes, and bilateral adrenal masses. At this time our differentials included lymphoma, thymic cancer, metastatic testicular cancer, germ cell tumor, or infectious etiology. Scrotal ultrasound was not suggestive of testicular malignancy. Lactate Dehydrogenase was elevated at 800 concerning for germ cell tumor. Core needle biopsy of the mediastinal mass was suggestive of high-grade thymic carcinoma. An adrenal biopsy was positive for poorly differentiated thymic cancer. The diagnosis of metastatic thymic cancer was established. Oncology was consulted and chemotherapy with cisplatin, doxorubicin, and cyclophosphamide was initiated. Despite chemotherapy, his symptoms worsened and a repeat CT scan at 6 months showed enlargement of the primary tumor to 10x10 cm with infiltration of the sternum and anterior chest wall, enlargement of the bilateral adrenal metastasis, invasion into the right hepatic lobe, kidneys and retroperitoneal carcinomatosis. Due to the advanced nature and poor prognosis of the disease, the patient refused further chemotherapy and decided palliative care. DISCUSSION: Thymic epithelial tumors have an indolent clinical course and are often associated with vague symptoms. Paraneoplastic syndromes associated with thymic cancer include Myasthenia gravis and rarely pure red cell aplasia or hypogammaglobulinemia. Gold standard treatment for thymic neoplasms at any stage is surgical resection. In advanced cases, cisplatin-based chemotherapy is recommended. Pembrolizumab is an accepted option for refractory cancer. Every patient is given post-operative radiotherapy to reduce the chance of recurrence. CONCLUSIONS: 1) Though thymic cancers are uncommon, it must always be included in the differentials for a patient presenting with a mediastinal mass. 2) The prognosis of thymic carcinoma is generally poor and tumor stage is the most important prognostic indicator. Reference #1: Sharma, S. and L. Dawson, A Rare Tumor with a Very Rare Initial Presentation: Thymic Carcinoma as Bone Marrow Metastasis. Case Reports in Pathology, 2017. 2017: p. 6497376. Reference #2: Nishino M, Ashiku SK, Kocher ON, Thurer RL, Boiselle PM, Hatabu H. The thymus: a comprehensive review. RadioGraphics. 2006;26:335–348. Reference #3: A. Marx, J. K. C. Chan, J.-M. Coindre et al., "The 2015 World Health Organization Classification of tumors of the thymus: continuity and changes,” Journal of Thoracic Oncology, vol. 10, no. 10, pp. 1383–1395, 2015. DISCLOSURES: No relevant relationships by Alisha Grewal, source=Web Response No relevant relationships by Ricardo Herrera, source=Web Response No relevant relationships by Jonathan Munoz, source=Web Response No relevant relationships by Tarreq Noori, source=Web Response No relevant relationships by kinnari SHAH, source=Web Response