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Accessory parotid gland tumors are relatively rare; hence, adequately detailed clinical analyses of these tumors are difficult to perform at a single institution. In this report, we describe the findings for 65 patients [29 men, 36 women; median age, 51 (9-81) years] with accessory parotid gland tumors, consisting of 4 cases documented by us and 61 cases previously reported by other Japanese authors. Approximately 50% of the patients were treated in an otolaryngology department, while the remaining patients were treated in plastic surgery, oral surgery, or dermatology departments. In 4 patients, the results of preoperative fine-needle aspiration cytology indicated that the tumor was benign; however, the postoperative histopathology results revealed malignant tumors. The frequencies of malignant and benign tumors were 44.6% (n = 29) and 55.4% (n = 36), respectively. Mucoepidermoid carcinoma and pleomorphic adenoma were the most frequent types of malignant and benign accessory parotid gland tumors, respectively. Among the various surgical methods that were used, such as direct cheek and intraoral incisions, a standard parotidectomy incision was the most preferred treatment approach for these tumors. Recently, an endoscopic approach has also been found to yield satisfactory results. An optimal approach should be selected after evaluating the advantages and disadvantages of these methods. No definite guidelines are available regarding the choice of elective neck dissection and postoperative radiation therapy for malignant accessory parotid gland tumors. Although tumor resection (plus elective neck dissection) and postoperative radiation therapy have been frequently performed for various kinds of malignant accessory parotid gland tumors to date, additional studies are needed regarding the criteria for selecting elective neck dissection and postoperative radiation therapy. Since the malignancy rate for accessory parotid gland tumors is higher than that for parotid gland tumors, the possibility of malignancy (especially mucoepidermoid carcinoma and carcinoma ex pleomorphic adenoma) should be considered when resecting accessory parotid gland tumors, even if the results of preoperative fine-needle aspiration cytology indicate that the tumor is benign.

We reported a rare case of pleomorphic TSH-producing pituitary adenoma with calcification and reviewed the literature. A 25-year-old female was admitted to our hospital with a complaint of anterior neck swelling. An endocrinological examination demonstrated elevated serum levels of free triiodothyronine (FT3: 5.6 pg/ml), free thyroxin (FT4: 2.2 ng/dl), TSH (5.85 microIU/ml), and TSH a-subunit (5.9 ng/ml), whereas a physical examination revealed no goiter. CT scan showed a suprasellar isodensity mass with dense calcification. Contrast-enhanced T1-weighted images revealed a less enhancing tumor extending from the left upper portion of pituitary fossa into suprasellar cistern. The patient underwent gross total removal of the tumor via the right pterional approach. Microscopically, medium-sized to enlarged tumor cells with marked pleomorphism and prominent calcification were observed. The tumor cells displayed positive reaction for TSH (beta-subunit). The MIB-1 index averaged 2.9%. The histological diagnosis was a pleomorphic TSH-producing pituitary adenoma. Postoperatively, the serum levels of FT3, FT4, TSH, and TSH alpha-subunit decreased to normal range. Follow-up MR images showed no evidence of recurrent tumor 3 years after the resection. All of six patients with densely calcified TSH-producing pituitary adenoma, previously reported in the literature, remained well without tumor recurrence. We suggest that this type of TSH-producing pituitary adenoma may be associated with favorable prognosis despite histologically pleomorphic appearance.

The term "malignant mixed tumor" is usually synonymous with "carcinoma in pleomorphic adenoma," a secondary carcinoma developing in pre-existing pleomorphic adenoma. However, it sometimes indicates a group of tumors consisting of carcinoma in pleomorphic adenoma, carcinosarcoma (true malignant mixed tumor) and metastasizing benign mixed tumor, the latter 2 being the most infrequent. According to the data of the Japanese committee on TNM classification for salivary gland carcinomas, carcinoma in pleomorphic adenoma accounted for about 10% of all salivary gland carcinomas, both in the parotid and submandibular glands. The main type of carcinomas arising in pleomorphic adenoma were undifferentiated carcinoma, adenocarcinoma and squamous cell carcinoma. Crude 5- and 10-year survival rates were 54.7% and 42.7%, respectively. Invasive carcinomas and carcinomas of high grade malignancy carried worse prognoses. The treatment of choice for carcinoma in pleomorphic adenoma has consisted of en-bloc excision with wide margin. Invasive growth, facial nerve involvement, lymph node metastasis or high-grade malignant tumor are grounds for postoperative radiation therapy. The role of chemotherapy has not yet been well established.

We correlated the histopathology of 32 cases of salivary gland tumors with MR imaging and flow cytometric DNA analysis. All malignant tumors were invasive and/or had an ill-defined margin. Fifty-seven percent of the pleomorphic adenomas were shown as a high signal intensity area on T2 weighted images. Fifty-six percent of Warthin tumors were shown as a low or iso signal intensity area on T2 weighted images associated with the cystic portion. Sixty-seven percent of malignant tumors were characterized by DNA aneuploidy and/or a total percentage of the S-phase fraction plus the G2 + M fraction higher than 10%. It was less than 10% and the Ki-67 positive fraction was higher than 20% in all pleomorphic adenomas. The Ki-67 positive fraction was less than 20% in 78% of Warthin tumors. The histopathology of all malignant tumors, 86% of the pleomorphic adenomas, and 89% of Warthin tumors was correctly predicted by the combination of MR images and flow cytometry. We suggest that the MR images combined with flow cytometric analysis of fine needle aspiration-derived materials is useful in the pre-operative histopathologic diagnosis of salivary gland tumors.

Multifocal tumors within the same parotid gland are very rare. We treated 13 patients with multiple tumorous lesions within the unilateral parotid gland. We evaluated the multiple nodules by CT-sialography or magnetic resonance imaging (MRI). These imagings showed clearly two or more distinct nodular-appearing lesions. Recurrent pleomorphic adenoma (6 patients) was predominant, followed by Whartin's tumor (3 patients). The other lesions were two differential parenchymal tumors (polymorphous low grade adenoma/adenoma) within the same gland, a malignant lymphoma, a squamous cell carcinoma metastatic to the gland, and a tuberculous lesion. On palpitation, 9 of the patients had an unilateral tumor, one a palpable parotid mass in the gland, and the other four had two or more tumors in the unilateral gland. The patients with intra-parotid lymph node and metastatic lesions had extra-parotid cervical adenopathy. The clinical features and the differential diagnosis of the unilateral multiple tumorous lesions of the parotid gland are discussed.

Purpose: To evaluate the efficiency of dynamic contrast-enhanced magnetic resonance imaging (MRI) for the diagnosis of salivary gland masses., Materials and Methods: We retrospectively examined 19 salivary gland masses that were pathologically diagnosed by surgical operation or biopsy. We obtained T1- and T2-weighted images on MRI, performed dynamic studies on each mass and examined the correlation between enhancement patterns and pathological findings., Results: Four enhancement patterns were recognized on contrast-enhanced MRI: type 1 showed marked, homogeneous enhancement; type 2 slight, homogeneous enhancement; type 3 marginal enhancement; and type 4 poor enhancement of the mass. Most pleomorphic adenomas had a type 1 enhancement pattern, but two had a type 2 pattern. Pathologically, each mass enhancement pattern had different tumor cell and matrix components. Warthin's tumor generally showed the type 4 pattern. Primary malignant tumors of the salivary gland all showed the type 3 pattern, and pathological specimens showed many tumor cells along the marginal portion of the tumor. One inflammatory cyst and one Warthin's tumor also showed the type 3 pattern. Except for metastatic renal cell carcinoma, the enhancement patterns of late phase images and dynamic study images were the same., Conclusions: Dynamic MRI added little diagnostic information about salivary gland masses, but the contrast-enhanced MR features correlated well with the pathological findings.