11/615. Histologic transformation of polymorphous low-grade adenocarcinoma of salivary gland. Polymorphous low-grade adenocarcinoma of salivary gland origin (PLGA) was initially described in 1984 and has since become an established clinicopathologic entity. Owing to the indolent nature of PLGA and its relatively recent description, the full clinicopathologic spectrum of this entity has not been elucidated fully. Transformation to a histologically different-appearing lesion or progression to a higher histologic grade has not been reported. We describe 2 PLGAs arising in the palate and associated with multiple locoregional recurrences that were treated with excision and radiation therapy. This was followed by histologic transformation to a higher grade neoplasm after 17 and 26 years, respectively. The histologic appearance after transformation was characterized by a predominantly solid and cystic growth pattern, nuclear atypia with prominent nucleoli, and foci of necrosis. High-grade transformation of PLGA may occur after a protracted clinical course with multiple recurrences of typical PLGA. The possible role of radiation therapy as an initiator of this transformation merits further study. Tumors with these histologic features should not be included under the rubric of typical PLGA. Segregation of these neoplasms will allow further study of their biologic potential, particularly with regard to possible increased rates of local recurrence and metastasis. ( info) |
| myoepithelioma is a rare form of salivary gland tumor composed entirely of myoepithelial cells. It represents about 1 to 1.5% of all salivary gland tumors and is most frequently located in the parotid. The authors present a case of myoepithelioma of the gingiva. The tumor presented a focal strong positivity for cytokeratins, a diffuse positivity for S-100 protein, and a rare focal positivity for actin. No duct formation was observed. myoepithelioma must be differentiated from several benign and malignant epithelial and mesenchymal tumors. ( info) |
13/615. Sialadenoma papilliferum of the palate: case report and literature review. Sialadenoma papilliferum (SP) is a rare tumor of salivary gland ducts which bears a strong histologic resemblance to the more common syringocystadenoma papilliferum (SCAP). We report a case occurring on the palate of a 50-year-old man, and review the clinical and histologic features of this tumor. Because of the histologic similarities between these two tumors and squamous papillomas, polymerase chain reaction (PCR) for human papilloma virus (HPV) dna was performed on this tumor and on two cases of SCAP, with negative results. To our knowledge, this is the first case report of SP in the dermatopathology literature. ( info) |
| Papillary cystadenoma of the minor salivary glands is a rare benign neoplasm that clinically resembles mucous cysts. Characteristic histological features are diagnostic. However, salivary gland histology is particularly difficult to interpret. Primarily, as further clinical and histological differential diagnoses have to take into account the well-differentiated cystic mucoepidermoid carcinoma and the papillary cystic type of acinic cell carcinoma, both malignant neoplasms of the salivary glands. We report on a 39 year old female with a bluish cystic lesion at the buccal mucosa, which occurred 14 years after the excision of a similar appearing, histologically proven mucous retention cyst at the same location. The histology of this tumor, however, revealed a papillary cystadenoma. Although rare, benign and malignant salivary gland neoplasms occur in minor salivary glands, and are clinically indistinguishable from mucous retention cysts. The dermatologist should be familiar with these differential diagnoses, since different therapeutic consequences result from an early diagnosis obtained by excision and histological examination of oral cystic tumors. ( info) |
| OBJECTIVE: To report 4 cases of hybrid carcinoma and to review the literature on these rare neoplasms of the salivary gland. methods: hematoxylin-eosin-stained, formalin-fixed, paraffin-embedded tissue sections from 3 parotid tumors and 1 palate tumor were examined. RESULTS: The cases were classified as adenoid cystic and mucoepidermoid carcinoma, adenoid cystic and epithelial-myoepithelial carcinoma, epithelial-myoepithelial and salivary duct carcinoma, and adenoid cystic and salivary duct carcinoma. All patients were men, 28 to 71 years old; 3 patients presented with parotid mass, and 1 patient presented with palatal mass. One patient presented with facial nerve paralysis and pain. The soft palatal tumor was a slowly growing mass with maxillary sinus involvement at the time of the diagnosis. All patients were treated with surgery and radiotherapy. CONCLUSIONS: Correct identification of 2 or more neoplastic entities will help assess the aggressiveness and metastatic potential of the tumor and influence the clinical course and treatment. ( info) |
16/615. Salivary duct carcinoma of the parotid gland: a case report. The authors report a case of a salivary duct carcinoma (SDC) of the parotid gland revealed by a facial palsy. The clinical and pathological features of this highly malignant neoplasm are described. The aggressive nature of this form demands a combined chemo-radio-surgical treatment; only early recognition and treatment are likely to result in a favourable outcome. ( info) |
17/615. Fine needle aspiration cytology of epithelial-myoepithelial carcinoma of salivary glands. A report of three cases. BACKGROUND: Epithelial-myoepithelial carcinoma is a rare, low grade malignant tumor of the salivary glands. Histologically, it has a biphasic cellular composition and exhibits a high degree of differentiation. The fine needle aspiration cytology of this rare tumor is rarely described in the literature. CASES: We report the fine needle aspiration cytology of three epithelial-myoepithelial carcinomas, arising in the right parotid, left parotid and minor salivary gland of the hard palate. Cytology showed a biphasic population consisting of cells of ductal epithelial and myoepithelial origin arranged in small clusters and sheets. The myoepithelial cells had small, uniform nuclei; ample, clear cytoplasm and distinct cell borders, while the ductal epithelial cells had larger, mildly pleomorphic nuclei and scanty cytoplasm. These ductal cells tended to form tubules among background sheets of clear myoepithelial cells. This feature, if present, was an important diagnostic clue. Hyaline material surrounding cell clusters and focal adenoid cystic carcinoma-like areas with orangeophilic globules were also not uncommon. CONCLUSION: While the cytologic appearance of epithelial-myoepithelial carcinoma may closely mimic that of other salivary gland tumors, such as adenoid cystic carcinoma, pleomorphic adenoma and basal cell adenoma, certain peculiar cytologic features may allow a distinction to be made on fine needle aspiration biopsy. ( info) |
| myoepithelioma, a rare benign salivary gland neoplasm, is a tumor composed entirely of myoepithelial cells. Unlike pleomorphic adenoma, these tumors lack any ductal epithelial differentiation, and manifest a minor stromal element. Previous cytogenetic and molecular genetic studies have mainly investigated pleomorphic adenomas and reported recurring specific chromosomal alterations at 8q12 and 12q13-q15 regions. The cell origin of these alterations, however, remains speculative. We report the cytogenetic analysis of a parotid myoepithelioma and discuss the putative origin for the cells with cytogenetic alterations. Our analysis shows 12q12 involved in a translocation with a previously unreported partner (1q), and nonrandom del(9)(q22.1q22.3) and del(13)(q12q22). Our results indicate that the myoepithelial cell is the source of those cells with chromosomal alterations, and that myoepithelioma shares 12q alterations reported in a subset of pleomorphic adenomas. ( info) |
19/615. Sialoblastoma and epithelial tumors in children: their morphologic spectrum and distribution by age. This commentary addresses the histologic spectrum of salivary gland neoplasms in children with emphasis on perinatal tumors. Histopathologically, perinatal tumors fall into four categories: 1) histologically benign with adult counterpart, 2) hamartomas 3) embryomas-sialoblastomas, and 4) histologically and biologically malignant adult analogue tumors. Although the criteria to serrate benign from malignant sialoblastomas are not well-established, the following histologic features would favor an aggressive clinical course: perineural and/or vascular spaces invasion, necrosis, and a cytologic atypia beyond the expected for embryonic epithelium. ( info) |
20/615. Pleomorphic adenoma of the nasal septum. Pleomorphic adenoma is the commonest benign tumour of the major salivary glands. It can also occur in minor salivary glands, mainly in the oral cavity, but also in other sites in the head and neck both within and outwith the upper aerodigestive tract. We present a rare case of pleomorphic adenoma of the nasal septum with consideration of the clinical management and a review of the literature. ( info) |