Synovial sarcoma in the prevertebral space can mimic malignant neurogenic neoplasm: Case report and literature review

Abstract

Synovial sarcoma, a rare malignant neoplasm with a poor prognosis, accounts for approximately 5%-10% of all primary soft-tissue malignancies worldwide. Typically affecting adolescents and young adults, it primarily manifests near the joints of the lower extremities. This study aimed to demonstrate that this tumor can also affect the prevertebral space. A 32-year-old male patient presented at our outpatient clinic with a 2-month history of upper limb numbness and a 1-month complaint of palpable neck mass. Imaging studies revealed a bulky, lobulated, and heterogeneous mass exhibiting heterogeneous enhancement. Furthermore, the mass caused expansion of the neuroforamen in the neck, initially suggesting a diagnosis of malignant schwannoma. However, a histopathologic examination suggested synovial sarcoma. The article provided a comprehensive review of the clinical, pathological, and radiological features of this condition. Additionally, it explored current treatment options and prognoses by referencing relevant literature.

Keywords: Imaging; Oncology; Synovial sarcoma; The retropharyngeal space.

Fig. 1

Anteroposterior (A) and lateral (B) radiographs of a 32-year-old male patient diagnosed with synovial sarcoma in the retropharyngeal space. (A) showed a large mass in the neck. (B) showed a large mass in the prevertebral space with the fifth cervical spine pathological fracture (black arrow). Thyrohyoid bone and trachea moved forward under compression (white arrow).

Fig. 2

Axial (A), axial contrast-enhanced CT image (B), MIP of CTA (C), and Sagittal reconstruction of the cervical spine of a synovial sarcoma in the retropharyngeal space of a 32-year-old male patient. A bulky, lobulated, heterogeneously enhancing mass measuring 11.0 × 5.8 × 8.1 cm was observed. Mild enhancement was noted following intravenous administration. Prominent tumor vascular structures resembling “caput medusae” were visible centrally within the lesion (black arrow in C), and the tumor eroded into the spinal canal (thick arrow in C). The fifth vertebral body showed osteolytic destruction with compression fracture (black arrow in D, bone window).

Fig. 3

Axial fat-suppressed T2W image: (A) 3.0T TE 85, TR 4300; (B) axial T2W image; (C) coronal T2W image; (D) sagittal T2W image; (E) axial fat-suppressed T1W; (F) axial fat-suppressed T1W image postgadolinium; (G) Coronal T1W image postgadolinium; and (H) sagittal T1W image postgadolinium, of synovial sarcoma in the retropharyngeal space in a 32-year-old male patient. A large, irregularly-shaped mass measuring 11.0 × 5.8 × 8.1 cm was observed, displaying heterogeneous enhancement following intravenous administration. The mass exhibited focal hemorrhagic necrosis (indicated by a long white arrow in images A, B, E, and F), invasion of the intervertebral foramen and spinal canal (indicated by a white arrowhead in images A, B, and F), prominent tumor vascular structures with a flow void effect (indicated by a white arrow in image C), erosion of the fourth to sixth cervical vertebrae (with a slight increase in T2WI signal in image D), and peritumoral edema (indicated by a short white arrow in image A).

Fig. 4

(A) Axial contrast-enhanced CT image; (B) Axial fat-suppressed T2W image; (C) Axial fat-suppressed T1W; and (D) Axial fat-suppressed T1W image post-gadolinium after 6 months of adjuvant chemotherapy of synovial sarcoma in the retropharyngeal space in a 32-year-old male patient. The lesion was significantly reduced, with new calcification (A, black arrow) and focal bleeding appearing at the liquid-liquid level (C, black arrow). The white arrow and short white arrow in B showed iso- and high-signal tumor parenchyma with a low bleeding signal, making a “triple sign.”