Results
Bell’s palsy (idiopathic FNP) was observed in 157 out of all 253 patients with FNP (62.06%) who had reported to the outpatient department and emergency unit. Other reasons of FNP included: head trauma with skull base fracture, facial trauma, complication of acute or chronic ear infection, facial nerve schwannoma, middle ear squamous cell cancer (Table 1).
In Bell’s palsy group 121 / 157 patients (77%) achieved a complete or partial regression of the face paralysis within 3 months, in 36 (22.92%) it remained permanent, despite typical treatment. In all patients with irreversible FNP, HIV infection and Lyme disease were excluded and the level of antinuclear antibodies was within normal limits. In 32 out of 36 cases the reason of permanent FNP was not found. In 4 patients (2.54% of all “Bell’s cases” and 11.11% of irreversible “Bell’s cases”), in MRI of the neck there was found a mass in the deep lobe of the parotid gland, in one patient infiltrating the skull base. The largest size of the tumor was 1.5, 2.0, 2.1 and 2.3 cm, respectively. Fine-needle aspiration biopsy confirmed malignant process while final histopathology adenoid cystic carcinoma in all analyzed cases.
The patients’ details are presented in Table 2. In all cases the first symptom of parotid gland and skull base cancer was FNP, diagnosed as “Bell’s paresis”. In all patients, there was no palsy regression, therefore, further diagnostics was implemented. It included high resolution computed tomography (HRCT) of the temporal bone to exclude masked ear infection, ultrasound examination of the neck and salivary glands with linear probe and neurological consultation with head imaging (in 3 cases computed tomography (CT) while in 1 case both CT and MRI). When all results were within normal limits, diagnostic procedures were discontinued. In the above 4 cases, after 6 to 12 months of observation, reassessment with contrast-enhanced MRI of the head and neck was conducted. In all patients malignant process in the deep lobe of the parotid gland with infiltration of the main nerve trunk was revealed, in the absence of other symptoms and finally with a relatively low tumor mass volume. All patients were treated surgically - in 3 cases total parotidectomy with facial nerve resection was performed, while in patient with infiltration of the skull base lateral petrosectomy was necessary. All patients had adjuvant irradiation and are still under control. In 2 patients there are no signs of local, regional or distant dissemination of the disease. In other 2 metastases to the lungs have been detected in the 11th and 28thmonth of follow-up.
A proposal of diagnostic algorithm for patients with irreversible FNP was presented in Fig.1.