A case of parotid mucoepidermoid carcinoma complicated by fatal gastrointestinal bleeding.

Abstract

Mucoepidermoid carcinoma is one of the most common of the salivary gland neoplasms. Histologically, it is classified as either a low-, intermediate-, or high-grade tumor, and there are significant differences in prognosis among the different grades. Patients with low-grade disease have an excellent chance of survival. High-grade tumors behave aggressively, and they frequently manifest as local recurrences and distant metastases. We describe a case o[ a high-grade mucoepidermoid carcinoma of the parotid gland that had metastasized to the skin, stomach, and liver. The disease culminated in a rapidly fatal bleeding from the stomach metastasis. Such a complication is unusual and to our knowledge has not been previously reported. We briefly discuss the clinical features, biologic behavior, and treatment of this tumor.

Introduction

Mucoepidermoid carcinoma of the salivary gland was first reported by Stewart et al in 1945. (1) They described an unusual salivary gland neoplasm that contained epidermoid and mucus-secreting cells, which were thought to arise from the salivary gland ducts. Most cases of mucoepidermoid carcinoma are located in the parotid gland. (2)

Microscopically, four types of cell can be identified: mucin-producing, squamous, intermediate, and clear. Tumors are graded according to a three-tiered scoring system, which is based on an evaluation of several morphologic characteristics: the amount of intracystic component, the type of cell composition, the pattern of invasion, the presence or absence of necrosis, the mitotic count, and the degree of nuclear pleomorphism. (3) The total score establishes whether the tumor is classified as a low-, intermediate-, or high-grade carcinoma. A highgrade tumor is characterized by a smaller amount of intracystic component, a higher mitotic count, and the presence of neural invasion, necrosis, and anaplasia. The histologic grading of mucoepidermoid carcinomas of the major salivary glands correlates well with the clinical, pathologic, and flow cytometric factors that influence prognosis and overall survival. (4) For example, lymph node metastasis is seen in 75% of high-grade tumors, but in only 20% of intermediate-grade tumors. In this article, we describe a fatal case of a high-grade mucoepidermoid carcinoma of the parotid gland that had metastasized to the skin, stomach, and liver. We also briefly discuss the clinical features, biologic behavior, and treatment of this tumor.

Case report

A 58-year-old man was referred to us for the management of a painful cheek mass of 1 month's duration. His medical history was otherwise unremarkable. Physical examination revealed the presence of an irregular, hard mass with a diameter of 5 cm in the left parotid region. The lump was fixed to the underlying tissue, and facial nerve palsy was evident. Blood test results were essentially normal; one exception was a slightly raised alkaline phosphatase level of 125 IU/L (normal: 40 to 100).

Magnetic resonance imaging (MRI) detected a 5.5-cm infiltrative left parotid tumor with an extracapsular spread to the adjacent sternocleidomastoid and digastric muscles (figure 1 ). Left upper cervical lymphadenopathy was also noted. Fine-needle aspiration cytology of the parotid mass was inconclusive. The chest x-ray was normal. Nasopharyngoscopy ruled out a nasopharyngeal carcinoma (which is relatively common in Southern China) metastatic to an intraparotid lymph node.

[FIGURE 1 OMITTED]

In view of the malignant nature of the lesion, left radical parotidectomy with neck dissection was planned. Intraoperatively, multiple skin nodules were noted in the cervical skin flap. Frozen-section analysis identified these nodules as high-grade mucoepidermoid carcinomas. Because of the extensive neck disease, the patient: was inoperable, and chemotherapy was planned? However, on postoperative day 6, the patient developed a distended abdomen and passed a massive amount of melena through the rectum.

An urgent esophagoduodenogastroscopy confirmed the presence of fresh bleeding from the stomach. Emergency laparotomy detected several bleeding tumors in the stomach and numerous deposits in the liver. Frozen-section analysis of these nodules confirmed the presence of a metastasis (figure 2). After the bleeding sites in the stomach were plicated, the wound was closed. The patient died 2 days later of multiple organ failure.

[FIGURE 2 OMITTED]

Discussion

Mucoepidermoid carcinoma of the parotid gland usually manifests as an asymptomatic swelling. Facial nerve palsy is observed in 17% of patients with intermediate- or high-grade disease. (6) Fixation or ulceration of the skin occurs in 38% of these cases. (6)

Most cases of mucoepidermoid carcinoma are treated with surgery. Frequently, the histologic grade of the tumor is not determined until the final resection specimen is examined. Therefore, the extent of resection depends on the aggressiveness of the tumor as determined by its size and location, as well as the presence or absence of regional or distant metastasis.

The use of the stage I to IV designation system for salivary gland mucoepidermoid carcinoma is well established. (7) Parotidectomy with preservation of the facial nerve is the treatment of choice for stage I and II disease. The presence of stage Ill disease or a local recurrence necessitates sacrificing the facial nerve and sometimes the overlying skin and/or adjacent: masseter muscle. The preferred approach to stage IV disease is radical parotidectomy, radical neck dissection, and postoperative radiotherapy. Radical neck dissection is recommended for tumors larger than 4 cm in diameter, irrespective of the clinical staging in the neck. (6) Elective neck dissection has also been suggested for high-grade tumors and larger tumors because of the high rate of occult neck node metastasis. (5)

The difference in prognosis between low- and highgrade disease is striking (6) For example, 5-year survival rates are 98 and 46%, respectively. (8) The incidence of distant metastasis has been reported to be 15% in patients with clinical stage III disease. (6) The most common site of distant metastasis is the soft tissue of the skin, followed by the lung, liver, and bone. (9) Metastasis to the stomach that results in fatal tumor bleeding is uncommon and to our knowledge has not been previously reported in the literature.

In retrospect, a more intensive metastatic workup for our patient--with panendoscopy, liver ultrasound, computed tomography of the brain, and whole-body bone scanning--could have changed our treatment approach from curative to palliative.

The clinical features associated with metastasis or death are advanced age, tumor size, and preoperative symptoms. (10) Furthermore, a significant correlation has been demonstrated between the clinical stage of mucoepidermold carcinoma and its histologic grading. Stage I tumors are usually of low histologic grade and are effectively controlled by conservative surgical procedures. Radical operations are often ineffective for patients with stage III and IV tumors, most of which are found to be of high histologic grade (2) These findings strongly suggest that therapeutic decisions should not be based solely on histologic grading.

References

(1.) Stewart FW, Foote FW, Becker WF. Mucoepidermoid tumors of the salivary glands. Ann Surg 1945;122:820-44.

(2.) Spiro RH, Huvos AG, Berk R, Strong EW. Mucoepidermoid carcinoma of salivary gland origin. A clinicopathologic study of 367 cases. Am J Surg 1978;136:461-8.

(3.) Batsakis JG, Luna MA. Histopathologic grading of salivary gland neoplasms: I. Mucoepidermoid carcinomas. Ann Otol Rhinol Laryngol 1990;99:835-8.

(4.) Hicks M J, el-Nagger AK, Flaitz CM, et al. Histocytologic grading of mucoepidemoid carcinoma of major salivary glands in prognosis and survival: A clinicopathologic and flow cytometric investigation. Head Neck 1995;17:89-95.

(5.) Armstrong JG, Harrison LB, Thaler HT, et al. The indications for elective treatment of the neck in cancer of the major salivary glands. Cancer 1992;69:615-9.

(6.) Healey WV, Perzin KH, Smith L. Mucoepidermoid carcinoma of salivary gland origin. Classification, clinical-pathologic correlation, and results of treatment. Cancer 1970;26:368-88.

(7.) Hermanek P, Sobin LH, eds. TNM Classification of Malignant Tumours. 4th ed. New York; Berlin: Springer-Verlag, 1987:30-2.

(8.) Jakobsson PA, Blanck C, Eneroth CM. Mucoepidermoid carcinoma of the parotid gland. Cancer 1968;22:111-24.

(9.) Evans HL. Mucoepidermoid carcinoma of salivary glands: A study of 69 cases with special attention to histologic grading. Am J Clin Pathol 1984;81:696-701.

(10.) Goode RK, Auclair PL, Ellis GL. Mucoepidermoid carcinoma of the major salivary glands: Clinical and histopathologic analysis of 234 cases with evaluation of grading criteria. Cancer 1998;82:1217-24.

From the Division of Head and Neck/Plastic, Reconstructive and Burns Surgery, Department of Surgery (Dr. To, Dr. Pang, and Dr. Cheng), the Oral Maxiliofacial Surgery and Dental Unit (Dr. W.-M.Tsang), the Department of Anatomical and Cellular Pathology (Dr. Tse), and the Division of Otorhinolaryngology, Department of Surgery (Dr. W.S.S. Tsang), Prince of Wales Hospital, The Chinese University of Hong Kong. Reprint requests: Prof. Edward W.H. To, Division of Head and Neck/ Plastic, Reconstructive, and Burns Surgery, Department of Surgery, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR. Phone: [phone]; fax: [phone]; e-mail: [e-mail]