Giant pleomorphic adenoma in the parapharyngeal space: report of 2 cases

Giant Parotid Pleomorphic Adenoma with Atypical Histological Presentation and Long-Term Recurrence-Free Follow-Up after Surgery: A Case Report and Review of the Literature

Salivary gland tumors (SGT) comprise 3% of all head and neck tumors, are mostly benign, and arise frequently in the parotid gland. Pleomorphic adenoma (PA) is the commonest SGT, representing 60-70% of all benign parotid tumors. Clinically, parotid PA presents as irregular, lobulated, asymptomatic, slow-growing preauricular mass, involving both superficial and deep lobes, and could grow to gigantic proportions. Histologically, PA has epithelial and mesenchymal elements in chondromyxoid matrix and is managed surgically. Based on a review of 43 cases reported in English literature since 1995, giant parotid PA is reported as large as 35 cm (diameter) and 7.3 kg (resected weight). Although rare, 10 cases of malignant transformation were reported in the review. Surgical management included extracapsular dissection (ECD), superficial parotidectomy, and total parotidectomy for benign tumors, and adjuvant radiation or chemotherapy for malignant tumors. We further present the case of a 36-year-old healthy male with slow-growing and asymptomatic giant parotid PA, of 4-year duration. The patient presented with firm, lobulated preauricular swelling, provisionally diagnosed as PA based on radiographic and cytological findings. The tumor was resected through ECD, and the patient had uneventful postoperative recovery and a 7-year recurrence-free follow-up period. Histological examination revealed epimyoepithelial proliferation punctuated by chondromyxoid areas, with extensive squamous metaplasia and keratin cysts. To the best of knowledge from indexed literature, giant parotid PA is rarely reported in Saudi Arabia. In addition to its rarity, this case is reported for its benign nature despite atypical histological presentation, successful surgical management without complications, and long-term recurrence-free follow-up. Based on this report, clinicians must be aware of atypical histological presentations associated with PA and plan suitable surgical management and follow-up to avoid morbidity. Nevertheless, attempts must be made to diagnose and manage these lesions at an early stage and before they reach gigantic proportions.

Parotid tail pleomorphic adenoma extending to the parapharyngeal space

Parapharyngeal space tumors are rare, accounting for 0.5% of head and neck neoplasms. Most of them are benign and originate in the salivary glands, especially the pleomorphic adenoma. We presented a 47-year-old man with parotid tail pleomorphic adenoma extending to the parapharyngeal space. The patient applied to our clinic with the complaints of a painless mass on his neck and in his mouth for 3 months. After fine needle aspiration biopsy, the mass was diagnosed as pleomorphic adenoma. The patient was hospitalized and operated in our clinic. As we see in literature review, parapharyngeal space tumors are rare, and most of them are pleomorphic adenomas arising from the deep lobe of the parotid gland and extend into the PPS.

Management of parapharyngeal giant pleomorphic adenoma

INTRODUCTION

Pleomorphic adenoma (PA) is found rarely in the parapharyngeal space (PPS). Because of late diagnosis due to slow growth, close proximity to vital neurovascular structures and risks of surgery, it poses a great difficulty for both diagnosis and surgical management. The preferred surgical approach to the PPS is the cervical-transparotid including a total parotidectomy with facial nerve preservation combined with a cervical access for dissection of cranial nerves and vascular structures thus allowing a safe removal of the tumor together with the parotid deep lobe. We report herein our experience in the management of giant PAs involving the prestyloid PPS and describe a not well-documented transparotid route by preservation of the parotid superficial lobe in combination with an intraoral approach.

PATIENTS AND METHODS

In this retrospective study, three cases of patients having giant PAs involving the PPS are evaluated. All patients had signs of foreign body sensation in the throat and a growing mass bulging in the oropharynx. Diagnosis was based on MRI and upon preoperative intraoral biopsy. The average tumor size was 5.7 cm. Patients underwent surgery and excision of tumors via transparotid-intraoral approach. In two cases, the superficial lobe was preserved and afterwards put back in its anatomic location.

RESULTS

All patients were discharged without complications, and no recurrences were observed.

CONCLUSIONS

Preoperative diagnosis management of PPS giant tumors should be based on imaging and upon open transoral biopsy if possible. The transparotid-intraoral approach provided adequate visibility to remove large PAs involving the prestyloid PPS.

[Giant pleomorphic adenoma of the parotid gland]

INTRODUCTION

Slow evolution pleomorphic parotid adenoma may be diagnosed late. These giant tumors have a functional, esthetic, and social impact. They raise prognostic issues because of the risk of degeneration. We present a case of a giant pleomorphic adenoma involving the parotid glands and try to explain the reasons for the diagnostic delay and describe therapeutic specificities.

CASE REPORT

A 54 year-old male patient consulted for swelling of the parotid region slowly evolving over the last 10 years. This lesion had been unsuccessfully treated by conventional methods. A painless 20cm long plurinodular mass was located in the right lateral cervical region. Its consistence was heterogeneous. The CT scan revealed a heterogeneous tumor with hyperdense and hypodense areas without any associate lesions. A total conservative parotidectomy was performed; the anatomopathological examination confirmed the diagnosis of a pleomorphic adenoma, weighing 1.2kg for a diameter of 19cm, without malignant degeneration. The postoperative evolution was uneventful.

DISCUSSION

The recommended treatment for giant parotid adenoma is total conservative parotidectomy. Besides its functional and esthetic impact, the giant parotid adenoma is at high risk of malignant degeneration. Documentation on the nature of the lesion, its evolutive potential, and an early surgical management could limit its incidence.