Delayed Distant Spinal Metastasis in Thymomas

Abstract

A case report. To demonstrate 2 cases of delayed distant spinal metastasis from a thymoma with comprehensive immunohisto-chemical analysis. Thymoma is a rare slow-growing cancer arising in the mediastinum. Thymomas usually grow invasively into surrounding structures. Distal spinal metastasis is uncommon. To date, only 4 cases with histological verification have been described. Patient 1: A 42-year-old female complained about back pain for 4 years. She underwent gross-total resection of a type B2 thymoma 8 years earlier without adjuvant therapy. Neurological examination revealed no deficits. Magnetic resonance imaging demonstrated an intraspinal extradural tumor at the level of L4-S1 with infiltration of vertebral body L5. A nearly total resection was performed via a partial L4 and L5 hemilaminectomy.Patient 2: A 62-year-old female was referred with segmental thoracic pain. She underwent a total of 6 surgical procedures for resection of a thymic carcinoma during a period of 13 years with a subsequently local radiation therapy and various chemotherapy cycles. Magnetic resonance imaging revealed an intraspinal extradural tumor at the level of T9-T10 with infiltration of vertebral body T9-T10. A gross-total tumor resection was performed via a costotransversectomy and facetectomy T9-T10. Patient 1: The tumor cells were strongly positive for AE1/3- and CK5/14-specific antibodies. Most of the immature T-cells expressed CD3. CD1a, CD5, and TdT expression was observed in a smaller portion. The findings were consistent with the diagnosis of a spinal metastasis of the known type B2 thymoma.Patient 2: The tumor cells were CK5/14 and CK19/20 positive. Only the infiltrating lymphocytes were labeled with CD3-specific antibodies. Histopathological findings revealed a metastasis of a previously resected well-differentiated thymus carcinoma. We recommend surgical resection because metastasis of thymoma may infiltrate nerve roots and compress the spinal cord. A multidisciplinary approach is required to manage long-term sequelae.