Introduction: The spine is the most common site for bony metastasis, with cancers from lungs, breast, and prostate as the predominant etiologies. Thymoma is a rare anterior mediastinal tumor. Little is known about the natural history of metastatic thymoma to spine due to its rare occurrence. Currently, no treatment guidelines exist due to variability in treatment modalities and reported outcomes as well as lack of thorough case series and literature review.

Methods: A 38 year-old female, presenting with left flank pain radiating to the lower abdomen/groin, was found to have a paraspinal mass with epidural extension into the left T12/L1 foramen causing cord compression. The patient underwent T12-L1 laminectomy for decompression and tumor resection, and posterior instrumented fusion from T11-L2. Post-operatively, the patient remained neurologically stable with the MRI demonstrating gross total resection. The patient is to receive adjuvant post-operative chemotherapy without need for radiation.

Results: Upon review of the literature, 16 case reports described 26 total patients with spine metastases secondary to thymoma/thymic carcinoma. Presentation varied widely, including age, neurological deficits, time from initial diagnosis to metastasis, and histological grading. The only widely accepted prognostic factor is completeness of tumor resection, while clinical staging and/or histological type may also have prognostic value.

Conclusions: Gross total resection and spinal decompression should be prioritized in cases of surgical intervention for thymic metastases to spine. Adjuvant chemotherapy and radiation are generally recommended. However, given the lack of standardized treatment algorithms, individualized regimens should be formulated on a case-specific basis.

Patient Care: The manuscript describes a rare case of malignant thymoma metastasized to thoracolumbar spine causing cord compression, surgically treated for gross total resection. Additionally, first complete literature review of all cases of thymic mets to the spine was performed. Only 16 case reports of 26 total patients were described. Given such rarity of the disease and limited published evidence of standardized care, there is a wide variation of treatment modalities used. With our first complete review of English literature, we attempt to elucidate treatment guidelines for thymic spine mets.

Learning Objectives: Extensive literature review of such rare metastatic disease to spine was performed to elucidate and help to standardize treatment algorithms.

References: - Marotta N, Mancarella C, Colistra D, Landi A, Dugoni DE, Delfini R. First description of cervical intradural thymoma metastasis. World J Clin Cases. 2015;3(11):946. doi:10.12998/wjcc.v3.i11.946. - Hong B, Nakamura M, Hartmann C, Brandis A, Ganser A, Krauss JK. Delayed Distant Spinal Metastasis in Thymomas. Spine (Phila Pa 1976). 2013;38(26):E1709-E1713. - Liu T, Qiu G, Tian Y. Thymic carcinoma with primary spine metastasis. J Clin Neurosci. 2011;18(6):840-842. - Farin A, Aryan HE, Abshire BB. Thymoma metastatic to the extradural spine. J Clin Neurosci. 2005;12(7):824-827. - Alafaci C, Salpietro FM, Grasso G, et al. Spinal cord compression by a metastasizing thymoma. Acta Neurochir (Wien). 1999;141(2):215-216. - Bilsky MH, Lis E, Raizer J, Lee H, Boland P. The diagnosis and treatment of metastatic spinal tumor. Oncologist. 1999;4(6):459-469. - Detterbeck FC, Parsons AM. Thymic tumors. Ann Thorac Surg. 2004;77(5):1860-1869. - Masaoka A, Monden Y, Nakahara K, Tanioka T. Follow-up study of thymomas with special reference to their clinical stages. Cancer. 1981;48(11):2485-2492. - Sasaki S, Fukushima T, Maruyama Y, et al. Two Cases of Thymic Carcinoma Initially Presenting as Bone Metastasis: A Clinical Report and the Usefulness of CD5 Immunohistochemistry for Assessing Bone Lesions. Intern Med. 2015;54(14):1781-1785. - Engels EA, Pfeiffer RM. Malignant thymoma in the United States: demographic patterns in incidence and associations with subsequent malignancies. Int J cancer. 2003;105(4):546-551.