Malignant transformation of a gigantic pleomorphic adenoma of the submandibular gland: a case report

Giant Pleomorphic Adenomas of Parotid Gland: a Case Series

The parotid gland is the largest salivary gland in the body. Pleomorphic adenomas (PA) are most common benign tumors of parotid gland. If left untreated, they can gradually attain the size which can weigh several kilograms. This paper highlights a case series of 15 cases diagnosed as giant pleomorphic adenoma arising in the parotid gland along with their management. A hospital based, observational study of 15 patients of PA of the parotid gland, > 10 cm in its widest dimension considered as giant, done at tertiary care ENT hospital over period of 9 years. The age of the patients ranged from 30 to 81 years with mean age 50.33 ± 15.30 years. There were 5(33.33%) males and 10(66.67%) females. The time duration of having tumor ranged from 5 to 20 years with mean duration of 10.4 ± 4.17 years and the largest tumor was 25 cm in its largest diameter. Mean weight of tumors was 2.72 ± 0.52 kg. One out of fifteen cases was detected as malignant in nature. All cases were treated by surgical excision without any complications. Pleomorphic adenoma of parotid gland can assume a giant proportion when timely surgical intervention is not done. We can build up confidence and hope for life in patients after complete surgical excision of giant PA.

Local Rhomboid Flap Reconstruction for Skin Defects After Excising Large Parotid Gland Tumors

Most parotid tumors grow slowly, and sometimes these patients do not request surgical treatment until the tumors become large and affect their appearance. The surgical treatment of these large tumors is usually accompanied by large skin defects after excision, and it is challenging for surgeons to close the defect primarily. This report describes the case of a 68-year-old man with a left parotid gland tumor (largest dimension, 110 mm) and the case of a 79-year-old man with a left parotid gland tumor measuring approximately 77 mm that had existed for decades. These patients underwent facial nerve dissection and parotidectomy with skin sacrifice. The large skin defects after the parotidectomy were successfully reconstructed with local rhomboid flaps. No facial palsy, wound disruption, flap edge loss, or major complications occurred after the surgeries. Except for the scars, the color of the cheek flap was not apparent from the periphery. In conclusion, local rhomboid flap reconstruction is a rapid and practical technique for reconstructing medium to large skin defects in the cheek and upper neck regions after tumor excisions. The flap was reliable in blood supply and cosmetic outcome.

[Squamous cell carcinoma on a pleomorphic adenoma with amyloid stroma of the palate]

INTRODUCTION

Squamous cell carcinoma ex-pleomorphic adenoma (CXAP) is a malignant and rare mixed tumor. We report a new case.

OBSERVATION

A seventy-year-old woman consulted for a mass in the left hemi-face having evolved over the last 20years. The physical examination revealed a hard and large tumor invading all the palate. Computed tomography revealed a heterogeneous 8.5cm long maxillary mass. The diagnosis of CXAP was made on a biopsy. A histological study confirmed the diagnosis after surgical resection of the tumor, specifying its noninvasive character.

DISCUSSION

CXAP is generally located in the parotid gland; it is very rarely located in the palate. The degenerated epithelial component generally corresponds to an adenocarcinoma or an undifferentiated carcinoma; squamous-cell carcinoma is more rarely reported. The prognosis is excellent for the micro and noninvasive types. Surgery remains the treatment of choice.

[Epidemiology, diagnosis, and treatment of giant pleomorphic adenomas of the parotid gland]

Pleomorphic adenomas of the parotid gland can be slowly growing over the course of many years and may reach an enormous and disfiguring size associated with significant morbidity of the patients. To our knowledge, over the last 80 years 20 cases of giant pleomorphic adenomas (weight 1.2-26.5 kg) have been reported. These tumors occurred predominantly in women (90%). The mean period from initial clinical manifestation until definitive surgical treatment was 20.7 years. The mean age of the patients at the time of surgery was 58.9 years. Malignant transformation occurred in 15.8% of cases. It is likely that the reasons for delayed treatment are the patient's fear of surgery on the one hand, and insufficient medical advise on the other. We report on a 77 year old female who had a 40-year history of a growing parotid tumor that weighed 3.9 kg after resection. The implications of this case for diagnosis and treatment of giant pleomorphic adenomas, and a review of the world literature on these unusual parotid tumors, are presented.

Salivary Gland Tumors in Transgenic Mice with TargetedPLAG1Proto-Oncogene Overexpression

Pleomorphic adenoma gene 1 (PLAG1) proto-oncogene overexpression is implicated in various human neoplasias, including salivary gland pleomorphic adenomas. To further assess the oncogenic capacity of PLAG1, two independent PLAG1 transgenic mouse strains were established, PTMS1 and PTMS2, in which activation of PLAG1 overexpression is Cre mediated. Crossbreeding of PTMS1 or PTMS2 mice with MMTV-Cre transgenic mice was done to target PLAG1 overexpression to salivary and mammary glands, in the P1-Mcre/P2-Mcre offspring. With a prevalence of 100% and 6%, respectively, P1-Mcre and P2-Mcre mice developed salivary gland tumors displaying various pleomorphic adenoma features. Moreover, histopathologic analysis of salivary glands of 1-week-old P1-Mcre mice pointed at early tumoral stages in epithelial structures. Malignant characteristics in the salivary gland tumors and frequent lung metastases were found in older tumor-bearing mice. PLAG1 overexpression was shown in all tumors, including early tumoral stages. The tumors revealed an up-regulation of the expression of two distinct, imprinted gene clusters (i.e., Igf2/H19 and Dlk1/Gtl2). With a latency period of about 1 year, 8% of the P2-Mcre mice developed mammary gland tumors displaying similar histopathologic features as the salivary gland tumors. In conclusion, our results establish the strong and apparently direct in vivo tumorigenic capacity of PLAG1 and indicate that the transgenic mice constitute a valuable model for pleomorphic salivary gland tumorigenesis and potentially for other glands as well.