Facial paralysis due to a benign parotid tumour

Benign parotid mass and facial palsy: systematic review

INTRODUCTION

Parotid masses causing facial palsy are highly indicative of malignancy. A significant number of cases describing benign parotid disease causing facial palsy have been reported.

MATERIALS AND METHODS

We performed a systematic review of the literature to establish the aetiology, clinical features, investigations and management undertaken during these presentations to assess how these factors differed from malignant presentations and to establish an evidence-based algorithm for their management.

RESULTS

A total of 85 cases were identified from 78 articles. Cystadenolymphomas were the most common histopathological type (p = 0.034). Mean facial palsy recovery duration in neoplastic aetiology was longer than for infective aetiology (p = 0.033). A significant association existed between uncommon infective organisms and development of facial palsy (p = <0.0001).

CONCLUSION

Uncommon benign aetiologies are associated with facial palsy. Investigations and management should be guided by patients' clinical presentations, avoiding excessive treatment. Complete facial palsy recovery rates are high, although not immediate.

Facial Nerve Paralysis due to a Pleomorphic Adenoma with the Imaging Characteristics of a Facial Nerve Schwannoma

Background Facial nerve paralysis in a patient with a salivary gland mass usually denotes malignancy. However, facial paralysis can also be caused by benign salivary gland tumors.

Methods We present a case of facial nerve paralysis due to a benign salivary gland tumor that had the imaging characteristics of an intraparotid facial nerve schwannoma.

Results The patient presented to our clinic 4 years after the onset of facial nerve paralysis initially diagnosed as Bell palsy. Computed tomography demonstrated filling and erosion of the stylomastoid foramen with a mass on the facial nerve. Postoperative histopathology showed the presence of a pleomorphic adenoma. Facial paralysis was thought to be caused by extrinsic nerve compression.

Conclusions This case illustrates the difficulty of accurate preoperative diagnosis of a parotid gland mass and reinforces the concept that facial nerve paralysis in the context of salivary gland tumors may not always indicate malignancy.

Parotid Warthin's tumour Bristol Royal Infirmary (1985-1995): a study of histopathology in 33 cases

This is a study of 33 (32 patients) confirmed Warthin's tumours (adenolymphomas) treated surgically at Bristol Royal Infirmary (1985--1995) focussing specifically upon 17 salient histopathological features together with capsular measurement by micrometry. Twenty-four out of 33 tumours had 'thin' capsules (< or = 200 microm), whereas 5/9 'thick' capsules were associated with gross tumour degeneration. The degenerative features including cystic change, squamous metaplasia, corpora amylacea like bodies, etc. were quantified. Tumours were classified into subtypes (typical, stroma poor, etc). These variations were not associated with age or sex. In 20/33 tumours a marginal sinus suggested a lymph node origin. Fine needle aspiration cytology (FNA) smears showing degeneration features are a diagnostic problem, but histopathological features are reflected in such smears and their recognition enhances diagnostic precision, enabling controlled surgical enucleation, the ideal operation, to be performed in most cases. In this study only 12 tumours were so treated; 11 others received parotidectomy. The theories of histogenesis are reviewed and discussed.

Surgical techniques in the treatment of pleomorphic adenoma of the parotid gland: our experience and review of literature

This paper presents a retrospective study carried out on a sample of 100 patients affected by pleomorphic adenoma of the parotid gland and treated at the Department of Maxillofacial Surgery at the University of Rome "La Sapienza" between January 1, 1989 and December 31, 1997. For the diagnosis of this neoformation, cytological tests were performed on material taken from the neoformation using fine needle aspiration and ultrasound scan. In some selected cases, a CT examination of the head and neck with medium contrast or Nuclear Magnetic Resonance (NMR) was carried out. This study sets out to examine the most suitable treatment to be followed for the removal of the pleomorphic adenoma of the parotid gland. In 56 cases the patients underwent a superficial, conservative parotidectomy. Forty one patients had a total parotidectomy with the facial nerve left intact and one patient had a total parotidectomy where the marginal mandibular nerve of the facial nerve was damaged. The remaining two patients involved in the study were suffering from a recurrent pleomorphic adenoma and in these two cases a total parotidectomy was performed where the facial nerve was killed. The removal of the cranial nerve VII in these patients proved necessary because the nerve fibers had adhered to the surrounding scar tissue of the tumor, either after previous surgery or due to repeated chronic phlogosis of the gland.

Plasticity of the extracranial facial nerve

Although the expansion properties of peripheral nerves have been a matter of considerable study in recent years, investigations of the plasticity of cranial nerves, including the facial nerve, have been lacking. Clinicians, however, have long recognized the tenacity of facial nerve function in patients with slow-growing benign tumors that enormously distort the nerve. An experimental study was designed to assess whether tissue expansion techniques can be applied to the extracranial portion of the facial nerves of cats. In eight cats the frontozygomatic branch of the facial nerve was expanded by stages in seven sessions over a period of 40 days. The length of the nerve increased an average of 95% without significantly impairing nerve function. Pressure changes in the expander averaged 75 mm Hg during each stage of expansion. Electroneurography was performed after each injection of the expander. Statistical analysis of these data did not show consistent evidence of demyelination or denervation, and all but one cat exhibited a normal blink reflex and had normal electromyographic findings at the end of the experiment. Histologic examination of the expanded nerves, however, did show inflammatory changes, intraneural edema, and occasional demyelination.