Rare case of double looped ansa cervicalis associated with its deep position in the carotid triangle of the neck

Extracranial hypoglossal neurofibroma with a variant ansa cervicalis: a case report

PURPOSE

This case report aims to explore a rare combination of findings in a cadaver donor: variant ansa cervicalis, vagus (CN X) and hypoglossal (CN XII) nerve fusion, and extracranial hypoglossal neurofibroma.

BACKGROUND

The type of ansa cervicalis variation presented in this report has been documented in less than 1% of described cases. The CN X-CN XII fusion has been reported in one prior study. Additionally, hypoglossal neurofibromas are benign neoplasms of the peripheral nerve sheath. There are only two known cases of extracranial hypoglossal neurofibroma described in the literature.

CASE REPORT

The study investigated a swelling of the right CN XII in a 90-year-old female cadaver donor. Detailed dissection, examination of the region, and histopathological analysis of the mass followed. The entire course of CN XII and other cranial nerves were examined to exclude concurrent pathology. A fusiform enlargement of the right CN XII was observed in the submandibular region, measuring ~ 1.27 × 1.27 cm. The superior portion of the right CN XII was fused to the right CN X, exiting the jugular foramen. The superior root of ansa cervicalis, normally a branch of CN XII, was found to arise from CN X on the right side. The left CN XII and CN X were unremarkable. Histopathological examination revealed benign neurofibroma.

CONCLUSION

The anatomical variation and rare location of the tumor necessitate further investigation to better understand pathogenesis, clinical correlation, and surgical implications. This study furthers knowledge of this condition and contributes to the currently limited body of research.

Ansa cervicalis: a comprehensive review of its anatomy, variations, pathology, and surgical applications

The ansa cervicalis is a neural loop in the neck formed by connecting the superior root from the cervical spinal nerves (C1-2) and the inferior root descending from C2-C3. It has various anatomical variations and can be an important acknowledgment in specific operations of the neck region. This is a review the anatomy, variations, pathology and clinical applications of the ansa cervicalis.

Descendens vagohypoglossi: rare variant of the superior root of ansa cervicalis

Knowledge of variants in the formation and position of the ansa cervicalis is important in head and neck surgery, specifically in reconstructions of the tongue that use the infrahyoid muscles, and in the anastomosis of the ansa cervicalis to the recurrent laryngeal nerve when the laryngeal muscles have been paralysed. We describe a rare variant of the superior root of the ansa cervicalis, which had a contribution from the vagus and hypoglossal nerves. The inferior root was formed by the C2 and C3 ventral rami, but it passed medial to the internal jugular vein before it joined the superior root to form the loop.