– 66-year-old female:
– 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.
Teaching point: 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.