mercoledì 15 aprile 2009
Right sialolithiasis with sialodochitis, sialoectasia and sialadenitis
Near the right Warthin duct orifice, there is a signal void consistent with a duct stone. Proximal to that, there are segmental dilatations and stenoses consistent with sialodochitis, or chronic inflammatory change of the duct. Near the mylohyoid turn of the duct, there is another signal void consistent with a stone and proximally, there is a stenosis. In the superficial submandibular gland, there are patchy areas of T2 prolongation consistent with dilated ducts, or sialoectasia. In the deep portion of the submandibular gland, there are no secondary or tertiary ducts because they have closed off due to chronic inflammatory change. There is T2 prolongation of the right submandibular gland, in relation to the left, consistent with sialadenitis.
Diagnosis: Right sialolithiasis with sialodochitis, sialoectasia and sialadenitis
The submandibular gland is the second largest in the mouth. It has relatively viscous secretions, which can predispose to the formation of duct stones.
The submandibular gland has a superficial portion, which is superficial and inferior. The deep portion is deep to the mylohyoid muscles and superior to the superficial lobe. Wharton's duct arises from the deep portion of the gland.
Conventional sialography, with contrast injection of Wharton's duct under fluoroscopy, is a limited evaluation of the duct and the gland, if, as in this case, there is complete obstruction of the distal duct by a stone or stricture. Conventional sialography requires cannulation of the duct, which could be technically difficult. While CT is the best imaging modality to identify sialolithiasis, MR sialography gives the best evaluation of the gland. Sumi et al. established that MR sialography has good correlation between CT imaging findings and clinical findings.
Acute sialadenitis can be bacterial or viral. Purulent material can be milked from the duct. Complications can include formation of a fistula to the skin, an abscess or trismus, if the parapharyngeal space is involved. Also, rarely, Ludwig angina, with involvement of the submental and sublingual space, can occur.
Chronic sialadenitis presents with persistent colicky pain with eating. It is not as painful as acute sialadenitis. This is often associated with sialolithiasis.
Sialolithiasis is usually associated with the submandibular gland (70%). The stones are calcium phosphate or calcium carbonate. Formation may be related to calcium salt precipitation, epithelial duct injury or dehydration. Surgical excision is usually needed.
Autoimmune sialadenitis is usually associated with Sjögren's syndrome. MR findings include T2 prolongation of the parotid glands consistent with diffuse parenchymal destruction.