Parotid gland tumors

Understanding primary parotid squamous cell carcinoma - A systematic review

INTRODUCTION

The true incidence of primary parotid squamous cell carcinoma (SCC) is unknown and likely overestimated in the literature. The aim of this systematic review is to examine the diagnosis, aetiology and incidence of parotid SCC by analysing studies evaluating primary parotid SCC.

METHODS

A systematic search of Medline, EMBASE and Cochrane library was performed. A narrative synthesis was done.

RESULTS

A total of 14 observational retrospective studies on primary parotid SCC were included. There are currently no standard criteria for ascertainment of primary parotid SCC. Primary parotid SCC is thought to be due to squamous metaplasia within the ductal epithelium and subsequent invasive squamous carcinoma. Histological features that favour primary disease includes SCC confined to parotid parenchyma with no direct communication to the skin and the absence of mucin. Incidence of primary parotid SCC varied from 1.54 to 2.8 cases per million person-years. Around 30%-86% of patients recorded to have primary parotid SCC on clinical records, when scrutinised, were in fact secondary to parotid lymph node involvement following regional advancement from skin or upper aerodigestive tract SCC.

CONCLUSION

Primary parotid SCC is rare and it is currently a diagnosis of exclusion. Thorough clinical assessment including endoscopy, preoperative imaging and the scrutiny of histopathological findings allow for differentiation between primary and secondary SCC within the parotid. This thus affects both initial treatment and subsequent follow-up.

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.

Clinicopathological evaluation of parotid gland tumors: a retrospective study

Two hundred and thirty sequential parotid tumors seen from March 1985 to 1995 were reviewed for their clinical presentation, diagnostic evaluation, pathological diagnosis, treatment modalities, and age and sex distribution. An asymptomatic mass was the most common clinical presentation. All of the operations were performed by the same surgical team. Total and superficial parotidectomy was used for the treatment of the lesions and none of the patients underwent limited excision. Retrograde approach in 79 (34.4%) patients and anterograde approach in 151 (65.6%) was used. Eighteen patients with malignant tumors were followed up in cooperation with the radiation oncology clinic. Tumors were classified according to their histopathologic diagnosis. Among 192 (83%) benign and 38 (17%) malignant tumors, the most common benign tumor of parotid gland was pleomorphic adenoma (79.1%) while the most common malignant lesion was adenocystic carcinoma (44.7%). Incidences of pleomorphic adenoma, adenocystic and epidermoid carcinoma were greater in male patients. Complication rates in benign and malignant tumors were presented and statistically significant difference could not be found between anterograde and retrograde approach in terms of facial nerve injury (P > 0.05).

A clinicopathologic study of parotid gland tumors

PURPOSE

A review of 121 parotid gland tumors over a 10-year period was carried out.

METHODS

The clinical records were retrieved to analyze treatment modalities, history, pathology reports, and sex and age distribution.

RESULTS

Pleomorphic adenoma was the most common benign tumor (88.2%), with adenoid cystic carcinoma being the most common malignant tumor (7.4%). Pleomorphic adenoma was more common in women than in men. Clinical signs and symptoms were of no value in distinguishing between malignant and benign tumors. Malignant tumors tended to be more common in the elderly. Subtotal or total parotidectomy was used as the method of treatment.

Surgical treatment of salivary gland tumors

Two hundred fifteen patients (74.14%) with benign tumors and 75 patients (25.86%) with malignant tumors of the salivary glands were analyzed. One hundred eighty-five of these patients were followed for 1 to 20 years postoperatively. Of 150 benign tumors, recurrence was noted in 15 cases (9.75%). The 5-year recurrence rate was 7.82%. With the malignant tumors, recurrence was noted in 16 patients (51.6%). The 5-year recurrence rate was 27.75%.

Hamartoma of the parotid gland: a case report with immunohistochemical and electron microscopic study

A case of a solid parotid tumour in a 16-year-old boy is presented. Histologically, the tumour demonstrated some peculiar findings. An acinar pattern was predominant although every component seen in the normal salivary gland was present, namely, serous and mucous gland acini, ducts, myoepithelial cells, adipose and lymphoid tissue. Large eosinophilic granules were abundant in the large acinar cell cytoplasm. Immunohistochemically, the tumour demonstrated the proteins which are present in the normal parotid gland, for example, amylase, lactoferrin and lysozyme. Electron microscopic features were quite similar to those of normal parotid tissue except for accumulation of a large number of cytoplasmic granules in the acinar cells. There has been no previous report of a tumour with the same features as seen in this case. Our pathological diagnosis is hamartoma, although the possibility of hyperplasia or neoplasia can not be excluded.

Adenolymphoma of the parotid: aetiology, diagnosis and treatment

In order to study the changing clinical pattern, diagnosis and surgical treatment of adenolymphoma, the records of all 57 patients with a confirmed histological diagnosis, made at Bristol Royal Infirmary between 1951 and 1984, were reviewed; in 3 patients (5 per cent) bilateral lesions had been found. No characteristics emerged in a review of the history and clinical examination which would have enabled a correct preoperative diagnosis to be made. During the period of study the incidence of adenolymphoma increased 24-fold. (Parotid pleomorphic salivary adenomas increased in incidence by only 42 per cent over the same period). Before 1965 all patients were men; between 1965 and 1975 the male to female ratio was 3:1; between 1975 and 1985, 1.6:1. Of the 48 patients who had a relevant history taken 45 were smokers (93.8 per cent). It is postulated that tobacco consumption is important in the development of adenolymphoma, and has produced the changes in incidence and sex ratio. Fine needle aspiration biopsy cytology (FNAB) afforded the only method of achieving a pre-operative diagnosis. This was successful in 64.7 per cent. Superficial parotidectomy induced a 43 per cent incidence of facial nerve neurapraxia. Controlled enucleation reduced this to 8 per cent. Enucleation is the procedure of choice for adenolymphoma but can only be employed with confidence if an exact pre-operative diagnosis is made.

Surgical treatment of pleomorphic adenoma of the parotid gland: report of 110 cases

One hundred benign and ten malignant pleomorphic adenomas of the parotid gland were analyzed. Follow up ranged from two to 20 years. Of 54 cases of benign pleomorphic adenoma of the parotid gland, recurrence was noted in five cases (9.2%). The five-year recurrence rate was 17.2%. Of the six malignant pleomorphic adenoma, recurrence within the first ten years took place in four patients (66.6%).

Surgical parotid disease in Nigeria: a review of 100 cases

100 cases of surgical parotid disease are reviewed. Parotid cyst was the commonest non-neoplastic disease, followed by a parotid fistula. 73% of the cases were neoplastic conditions of which approximately 50% were malignant and the patients were much younger than those reported in other series.

Adenoidcystic carcinoma (cylindroma) of the parotid gland

Adenoidcystic carcinoma or cylindroma of the parotid gland is a slow-growing, relentless, and often lethal disease which kills usually by local occurrence and direct extension of the disease. The reported incidence of adenoidcystic carcinoma with reference to other parotid malignancies varies from 5% to 37%. The incidence in this series is 36%. The presence of facial nerve involvement adversely affects the long-term survival. Some authors regard facial nerve involvement as an indication of noncurability. The incidence of local pain is reported to be as high as 50% and is thought to be caused by perineural invasion by the tumor. This is well-documented histopathologically. There is no uniform or standard treatment for this disorder. Extensive resection of the parotid gland (including the facial nerve if there is any indication of involvement), followed by external irradiation to the parotid area and upper neck is the most rational approach to the problem. This is supported both in the review of the literature and from the present series. A radical neck dissection is not included as part of initial therapy unless there are clinically suspicious cervical nodes. Postoperative radiotherapy appears indicated in all cases of adenoidcystic carcinoma of the parotid gland. Four case histories are presented which demonstrate the hallmark characteristics of the disease, i.e. multiple cranial nerve deficits, facial pain and subsequent death by direct intracranial extension of disease. The protracted, relentless course of the disease is well-documented in one case in which 25 local recurrences developed over an 18-year period.

Experience with 1,360 primary parotid tumors

Experience with 1,360 primary parotid tumors seen at the Mayo Clinic during two fifteen year periods, 1940 through 1954 and 1955 through 1969, is reviewed. A comparison of histopathologic classification, type of treatment indicated, recurrence rates, and survival in the two periods reveals considerably greater understanding of all factors in the later fifteen year period. The relatively high mortality still encountered among patients with high grade malignant tumors of the parotid glands indicate the nature of the challenge still to be met. Based on the data in this study, it is our opinion that superficial or total conservative parotidectomy is best employed primarily for benign tumors and that the shift to more radical operative procedures should continue in the management of malignant tumors, especially those that are less well differentiated. For experienced surgeons, exceptions might be the small superficially located tumors or the tumors in the lower pole of the gland such as Warthin's tumors. Local excision with removal of a margin of parotid parenchyma might be justifiable in such cases.

Parotid gland tumors. Clinicopathologic study

The clinical findings and histologic features of 154 parotid gland tumors treated at the Health Sciences Centre, Winnipeg, Canada, from 1957 to 1970 were reviewed. The study illustrates a wide variation in the natural history and degree of malignancy of parotid tumors. Approximately 80 per cent were benign; among these, mixed tumors were by far the commonest. For most benign tumors, the recommended surgical treatment is wide local excision with an adequate margin of normal glandular tissue, except when subtotal or conservative total parotidectomy is required because of the size or location of the tumor. The facial nerve should be visualized and preserved. This approach prevents recurrences and minimizes facial nerve injury, since risk of neural injury increases with the extent of the surgical procedure. Total removal of the gland on the basis of the multicentricity or malignant transformation of these tumors is not supported by the findings of this study. For malignant tumors a more radical procedure, that is, subtotal or total parotidectomy with or without node dissection, with sacrifice of the facial nerve if necessary is advisable, depending on the type and anatomic location of the tumor.