Left carotid sheath posterior to the carotid bulb, internal, and external carotid arteries.
How does it look like?
Large oval avidly enhancing lesion displacing the carotid bifurcation anteriorly.
What is the differential diagnosis?
– Carotid bulb paraganglioma: avidly enhancing lesion with characteristic splaying of the internal and external carotid arteries (lyre sign).
– Glomus vagale: paragangliomas but of the vagus nerve, located posterior to the carotid arteries displacing them anteriorly.
– Vagal schwannoma: those that arises within the carotid sheath posteriorly but usually shows moderate enhancement compared with the avid enhancement of the paragangliomas.
– Since a few weeks eye movement disorder and diplopia of the left eye, tinnitus, and sinusitis.
– Non-enhanced CT of the orbits is performed (due to contrast allergy).
What are your findings?
Widened infraorbital canal left eye with thickening of the infraorbital nerve.
What is your differential diagnosis and do you want more imaging?
Yes, we want MRI to sort things out more.
Findings: Smoothly thickened T2 hyperintense, enhancing infraorbital nerve in its canal. No continuation posteriorly to the vidian canal or anteriorly to the pre-antral region. No pathologic paranasal sinus mass or pharyngeal mucosal mass indicating perineural tumor spread.
Less likely malignant cause like perineural tumour spread.
Biopsy is performed of right lacrimal gland, since clinically this was found to be prominent (radiologically slight asymmetry, slightly higher T2 signal).
Histopathology: IgG4 disease or dacryoadenitis.
After this, whole body scanning showed evidence of IgG4 disease in the pancreas also. Patient was treated with steroids.
Follow-up MRI: Decrease in size of the infraorbital nerve from 11 to 5 mm. Still high T2 signal, however, the decrease in size on steroids suggests other diagnosis than schwannoma, in this case probably involved in orbital IgG4 disease. Rare!
– Feels a lump in the neck when swallowing
In what space houses this lesion?
Mass in the right parapharyngeal space or deep part of parotid space. No parapharyngeal fat is visible, so either the lesion displaces the fat or it arises from it. It is certainly not from the carotid space, since the carotid arteries are displaced posteriorly. It is also not from the mucosal space since it compresses the lateral oropharyngeal wall, instead of arising from it.
Do you want further imaging to make a diagnosis and what?
MRI will provide you more details in head and neck lesions where the lesion arises from exactly, and what the origin is. MRI is made with T1, T2, and T1 with Gad and fat suppression.
What is your differential diagnosis?
Origin from deep parotid lobe, so DD benign or malignant salivary gland tumor, such as pleiomorphic adenoma, adenoid cystic of mucoepidermoid cell carcinoma. Radiologists are not good in differentiating benign from malignant lesions on MRI. Histopathology has to be done. DWI will help you a little, in that, malignant lesions have often lower ADC values, but also Wharthin tumors do so. DD rare schwannoma arises from V3 (mandibular nerve) in the true parapharyngeal space.
We performed ultrasound and cytologic punction. This turned out to be a fairly rare acinic cell carcinoma.
Malignant tumors of the salivary glands are well delineated and do not have to present as ill-defined lesions, nor have to have lymph node metastasis or perineural spread
There is a small lucency anterior to the vestibule, just lateral to the basal turn of the cochlea. Consistent with fenestral otosclerosis.
There are two types of otosclerosis:
1- Fenestral: is the most common type. It involves the bone anterior to the oval window and causes conductive hearing loss.
2- Retro-fenestral: involves the cochlear capsule and causes sensorineural hearing loss.
The two types can occur simultaneously.