Nerve root metastasis of gastric adenocarcinoma: A case report and review of the literature

Highlights • Metastatic involvement of peripheral nerves by perineural invasion from an adjacent cancer is not uncommon. • Nerve root metastasis without extension from an adjacent process has been seldom reported in case of solid tumors. • No cases of gastric adenocarcinoma metastasis to the nerves have been reported to date. • In case of known malignancy and refractory pain, the possibility of a nerve root metastasis should be considered.
Introduction Nerve root metastasis without extension from an adjacent process has been seldom reported in case of solid tumors. We describe a case of solitary nerve root metastasis of gastric adenocarcinoma, likely due to hematogenous spread. Case presentation A 75-year-old man presented with radiculopathy refractory to medical treatment. MRI and CT demonstrated a right-sided S1 nerve root mass involving the spinal ganglion in its intra-foraminal region with avid enhancement, initial erosive bone changes on sacral foramina and focal hyperaccumulation on 18F – FDG CT-PET, suspicious for metastasis. The histopathological examination confirmed a metastasis of gastric adenocarcinoma. Discussion A review of the current literature revealed only ten cases of hematogenous metastases to spinal nerve root ganglia; the primary lesions in those cases were an oat cell carcinoma of the lung, two cases of colonic adenocarcinoma, a case of uterine adenocarcinoma, a ductal breast carcinoma, a Ewing’s sarcoma, a Renal Cell Carcinoma, a gastro-intestinal stromal tumor, a follicular thyroid carcinoma, a pulmonary adenocarcinoma. Conclusion In the setting of a known malignancy, a nerve root metastasis should be considered in the differential diagnosis of a nerve root mass, although it occurs very rarely.