Surgical management of spinal metastases of thymic carcinoma: A case report and literature review

Abstract

Rationale: Metastatic thymic carcinoma in the spine is a rare disease with no standard curative managements yet. The objective of this study is to report a very rare case of spinal metastases of thymic carcinoma successfully operated by combination of instrumentation and cement augmentation together with adjuvant treatment. The management of these unique cases has yet to be well-documented.

Patient concerns: A 57-year-old man presented with a 6-month history of continuous and progressive back pain. The patient, who had been diagnosed of thymic carcinoma (stage IV B) for 3 years, received surgical treatment of median sternotomy thymectomy, followed by 3 cycles of chemotherapy and 12 cycles of radiotherapy.

Diagnosis: Magnetic resonance imaging (MRI) of spine showed spinal cord compression secondary to the epidural component of the T4 mass, with increased metastatic marrow infiltration of the left T4 vetebral body, which presented as a solid tumor. Post-operative pathology confirmed the diagnosis of spinal metastases of thymic carcinoma.

Interventions: The patient underwent exploratory surgery, circumferential spinal cord decompression, cement augmentation and a stabilization procedure via a posterior approach.

Outcomes: The patient's neurological deficits improved significantly after the surgery, and the postoperative period was uneventful at the 3-month follow-up visit. There were no other complications associated with the operation during the follow-up period.

Lessons: Taken together, the lesion's clinical features, imaging results, and pathological characteristics are unique. Combined efforts of specialists from orthopedics, neurosurgery, thoracic surgery, and medical oncology led to the successful diagnosis and management of this patient. Metastatic thymic carcinoma of the spine, although rare, should be part of the differential diagnosis when the patient has a history of thymic carcinoma and presents with back pain and radiculopathy. We recommend the posterior approach for spinal decompression of the metastatic thymic carcinoma when the tumor has caused neurological deficits. Osteoplasty by cement augmentation is also a good choice for surgical treatment.

Figure 1

(A–H) Preoperative transverse computed tomography showing the primary thymic carcinoma in the anterior mediastinum.

Figure 2

(A–D) Preoperative sagittal MRI scan revealing abnormal signal of T4 in keeping with diffuse metastatic infiltration caused by metastatic thymic carcinoma. MRI = magnetic resonance imaging.

Figure 3

(A–G) Preoperative coronal and transverse MRI images revealing spinal cord compression secondary to the epidural component of the T4 mass, with increased metastatic marrow infiltration of the left T4 vetebral body, which presented as a solid tumor. Tumor infiltrated through the T4 vetebral body into the left pedicle and posterior elements causing significant compression of the nerve root. MRI = magnetic resonance imaging.

Figure 4

(A) PA X-ray image of the thoracic spine obtained postoperatively. (B) Lateral X-ray image of the thoracic spine obtained postoperatively. PA = posteroanterior.

Figure 5

Pathologic histology of spinal metastases. (A–C) Microphotography showing characteristic nests of tumor cells separated by vascular septa (Zellballen) with cells showing significant nuclear pleomorphism with prominent nucleoli (H&E, original magnification 100x, 200x, and 200x). (D) AE1/AE3 immunostaining is strongly positive in the epithelial cells. (E) CD5 immunostaining shows strong, diffuse cytoplasmic staining in the tumor cells. (F) The sustentacular cells of the spinal metastases of TC showing characteristic staining of P63.