Low-grade Mucoepidermoid Tumor Research Articles

Mucoepidermoid Parotid Gland Tumor Found on Follow-up Radioiodine Scan for Differentiated Papillary Thyroid Cancer

This report presents a case of focal uptake in the right parotid gland found on a follow-up whole-body radioiodine scan 1 y after successful ablation of differentiated papillary thyroid carcinoma. After the parotid tumor had been excised, it was proven histopathologically to be a low-grade mucoepidermoid tumor. This case illustrates a 131I focus that was false-positive for thyroid carcinoma. The short period between radioiodine treatment and development of this parotid tumor creates doubt about a causal relationship. Induction of salivary gland tumors by radiation has been reported primarily in the setting of external radiotherapy. In the large volume of thyroid carcinoma patients treated with radioiodine across the world, such an occurrence has been rare.

Surgical resection of mucoepidermoid carcinoma at the carina in a 9-year-old boy

Mucoepidermoid carcinoma of trachea and bronchi is a rare tumor, especially in children. The authors report a case of 9-year-old boy with mucoepidermoid carcinoma at the carina. His presenting symptoms were hemoptysis of recent onset and intermittent cough of 2 years' duration. Preoperative assessment of the tumor was an intraluminal polypoid mass arising from the carina extending into the trachea and right main stem bronchus. A complete resection with reconstruction of carina was successful. The tumor was 12 mm in size, polypoid with a broad base. It had characteristic features of a low-grade mucoepidermoid tumor, namely, admixture of islands of intermediate cells and glandular components with invasion of submucosa. The patient is now 15 months postsurgery free of disease.

大唾液腺粘表皮腫症例の検討

We herein review our 7-year experience with 119 patients treated for parotid gland tumors. Mucoepidermoid tumors (METs) accounted for 5 of the 119 cases. Five low-grade METs and one high-grade mucoepidermoid carcinoma (MEC) of the parotid gland and submandibular gland were reviewed with an emphasis on the clinicopathologic aspects. Histologic grading of METs of the major salivary glands correlates well with prognosis and overall survival. A number of investigators have reported that low-grade METs are associated with a benign clinical course, while high-grade METs have an aggressive clinical course. The type of operation for METs should be chosen based on histologic grading. Subtotal parotidectomy, sparing the branches of the facial nerve was the operation of chosse for low-grade METs, while total paroidectomy with radical neck dissection and sacrifice of the facial nerve was performed for the high-grade MEC.Given the poor prognosis for MECs, adjunctive therapy such as postoperative radiation is indicated.

Childhood bronchial mucoepidermoid tumors

A very rare case of a childhood bronchial mucoepidermoid tumor is presented. A 4-year-old girl was hospitalized with prolonged pneumonia. Computed tomography of the chest showed a tumor with calcifications in the right upper lobe. Subsequently, the patient underwent right upper lobectomy. Histologically, the tumor was a low-grade mucoepidermoid tumor originating from the bronchus. Three years postoperatively there has been no evidence of disease. A review of the literature indicates that 30 cases of bronchial mucoepidermoid tumors in children have been reported. Symptoms result from associated bronchial obstruction. Children with recurrent or prolonged pneumonia should undergo aggressive diagnostic investigation by chest tomography or bronchoscopy. Appropriate therapy for childhood bronchial mucoepidermoid tumor is total resection of the lesion while sacrificing as little of the normal lung tissue as possible.

左側臼後三角部に再発し，全身転移をきたした粘表皮腫の１例

A case of a recurrent mucoepidermoid tumor of the left retromolar triangle with multiple metastasis is reported.A 66-year-old man came to the outpatient clinic of our hospital with a complaint of trismus. He had undergone irradiation and resection of a tumor on the left retromolar pad region 24 years ago. There had been no signs of tumor recurrence for 24 years.CT scans showed a high density area in the left infratemporal fossa. He was treated by segmental mandibulectomy and resection of the tumor. Histological examination of the resected specimen revealed that it was similar to the first lesion removed 24 years ago. About 1 year later, the tumor recurred and progressed to general metastasis, followed by death.Although this tumor was a well differentiated type mucoepidermoid tumor, recurrence and general metastasis occurred 24 years after primary treatment.This experience, indicates that patients with even low grade mucoepidermoid tumors should be followedup over the long term.

Oral sialocysts.

Epithelial-lined sialocysts of the minor oral salivary glands are rare when compared with the common mucous retention phenomenon or mucocele. One hundred twenty cases are reported and segregated into three distinct subtypes on the basis of clinicopathologic features. The true mucous retention cyst was most prevalent, occurring in patients older than 20 years, with no sex predilection. The floor of the mouth was the most common site. Reactive oncocytoid cysts arose in elderly patients and were more common among women. The buccal mucosa-mandibular vestibule was the favored site. Mucopapillary cysts are rare and may be confused histologically with low-grade mucoepidermoid tumors.

Melanin pigmentation in a mucoepidermoid tumor of a minor salivary gland

A low-grade mucoepidermoid tumor rich in melanin has been reported. According to the collective personal experience of the authors and a literature review, such lesions are thought to be rare. It is not anticipated that melanocytic participation will alter the prognosis; however, only long-term followup and reports of any similar lesions of salivary gland will assist in clarifying the nature and significance of this lesion.

SUBMANDIBULAR GLAND TUMORS

Tumors involving the submandibular gland are rare. However, the incidence of malignancy is much higher than in the parotid (approaching 50 percent). In addition, the 5-year survival rate in patients with malignant tumors of the submandibular gland is much poorer in our series--28 percent versus 71.8 percent for the parotid gland. Because of the poor prognosis in patients with malignant tumors involving the submandibular gland we feel that composite resections should be carried out for all tumors except low-grade mucoepidermoid tumors. In addition, postoperative radiation should be given for specific indications (detailed in the article).

Intraoral minor salivary gland tumors: Report of thirty-eight cases

This series of thirty-eight intraoral minor salivary gland tumors consists of twenty-six benign and twelve malignant tumors. Twenty-three of the twenty-six benign tumors are mixed tumors, and eight of the twelve malignant tumors are low-grade mucoepidermoid tumors. The palate was the favored site for benign tumors (fourteen cases), whereas malignant tumors occurred most frequently in the retromolar pad (five cases). The most common clinical feature of all tumors was a painless swelling. The wide variation in the incidence of malignancy shown in published series of minor salivary gland tumors may be a result of two factors: (1) variation in histopathologic criteria for malignancy and (2) type of institution from which a series is reported.

Diagnosis and management of parotid tumors.

It is commonly accepted that the management of parotid tumors calls for complete resection of the growth. But beyond this there is little agreement and the literature on the subject contains many contradictory statements. Perhaps the most vexing problem is whether mixed and low-grade mucoepidermoid tumors are benign or malignant. The decision is largely based on the likelihood of recurrence at the primary site; yet such recurrences depend not only on the growth potential of the tumor, but also on the surgical technique employed in extirpation of the mass. If any vestige of the diseased tissue is permitted to remain, the second appearance may clinically be classified as a recurrence, but, strictly speaking, it is a continuation of the uncontrolled original process. The first prerequisite for successful management of parotid tumors is correct assessment of the extent of involvement. Often it is assumed that mere enucleation of "encapsulated" mixed tumors