Case Of the Week (COW) 28 Sep 2014
Answer:
Left Vagal Schwannoma with left vocal cord palsy.
Findings:
Fullness and medial displacement of the left aryepiglottic fold. Thickening of the left vocal cord. Anteromedial displacement of the left arytenoid cartilage with medial displacement of the posterior vocal cord margin . Dilatation of the left piriform sinus. Enlargement of the left laryngeal ventricle. Combination of medialization of the posterior vocal cord margin and air distending left laryngeal ventricle results in the residual airway having a shape similar to a ship’s sail (coronal ct image) - “sail” sign.(REF:www.ajnr.org/content/31/8/1408) Solitary, well-circumscribed and medial to the carotid sheath homogeneously isoattenuated to the skeletal muscle. Heterogeneously bright on T2WI with intense inhomogeneous enhancement. ICA is displaced laterally and separate from IJV.
Discussion:
Benign slow-growing encapsulated nerve sheath tumor composed of Schwann cells in a collagenous matrix that can arise from cranial, peripheral, or autonomic nerve . Most extracranial schwannomas are found in the parapharyngeal space and are usually of vagal origin. Schwannomas do not fill the crotch of the carotid bifurcation. Schwannomas can be hypo, iso or hyperattenuated with variable texture (heterogeneous or homogeneous) and enhancement . The heterogeneity has been attributed to cystic degeneration, xanthomatous change, or areas of relative hypocellularity adjacent to densely cellular or collagenous regions. The vagus nerve runs between the IJV and ICA in the entire carotid sheath; hence vagal tumors tend to separate these vessels.
Contributed By:
Dr. Balaji Ayyamperumal
Tanjore Medical College
Answer:
Left Vagal Schwannoma with left vocal cord palsy.
Findings:
Fullness and medial displacement of the left aryepiglottic fold. Thickening of the left vocal cord. Anteromedial displacement of the left arytenoid cartilage with medial displacement of the posterior vocal cord margin . Dilatation of the left piriform sinus. Enlargement of the left laryngeal ventricle. Combination of medialization of the posterior vocal cord margin and air distending left laryngeal ventricle results in the residual airway having a shape similar to a ship’s sail (coronal ct image) - “sail” sign.(REF:www.ajnr.org/content/31/8/1408) Solitary, well-circumscribed and medial to the carotid sheath homogeneously isoattenuated to the skeletal muscle. Heterogeneously bright on T2WI with intense inhomogeneous enhancement. ICA is displaced laterally and separate from IJV.
Discussion:
Benign slow-growing encapsulated nerve sheath tumor composed of Schwann cells in a collagenous matrix that can arise from cranial, peripheral, or autonomic nerve . Most extracranial schwannomas are found in the parapharyngeal space and are usually of vagal origin. Schwannomas do not fill the crotch of the carotid bifurcation. Schwannomas can be hypo, iso or hyperattenuated with variable texture (heterogeneous or homogeneous) and enhancement . The heterogeneity has been attributed to cystic degeneration, xanthomatous change, or areas of relative hypocellularity adjacent to densely cellular or collagenous regions. The vagus nerve runs between the IJV and ICA in the entire carotid sheath; hence vagal tumors tend to separate these vessels.
Contributed By:
Dr. Balaji Ayyamperumal
Tanjore Medical College