Diagnostic difficulties in lesions of the minor salivary glands

A wide range of lesions arise from the intra-oral salivary glands, and often present a diagnostic challenge to specialists and generalists alike. Of the salivary neoplasms, pleomorphic adenoma is the most common, but its morphological diversity may bring several other entities to mind, notably polymorphous adenocarcinoma, particularly in a small incisional biopsy. Polymorphous adenocarcinoma in turn shares features with adenoid cystic carcinoma. Immunohistochemistry and molecular cytogenetic studies can assist diagnosis in the face of overlapping morphology. The other salivary neoplasms most likely to be encountered in the oral cavity are canalicular adenoma, mucoepidermoid carcinoma, secretory carcinoma and acinic cell carcinoma. Of the non-neoplastic conditions, necrotising sialometaplasia is most likely to be misdiagnosed as neoplastic on both clinical and histological grounds. However, careful consideration of the clinicopathological features of an adequate tissue specimen will enable correct diagnosis.     

Diagnostic approach to lymphoid lesions of major salivary glands

Among lesions of the major salivary glands (parotid, submandibular, and sublingual glands), those with a prominent lymphoid component are encountered frequently in the surgical pathology laboratory and range from reactive lesions to benign and malignant neoplasms. A majority of these lymphoid lesions have a co-mingled epithelial component, which also ranges from benign to malignant. As a result, many of these lesions have similar and overlapping histopathologic features, and attention to details, sometimes subtle, is required to accurately distinguish one from another. This review will discuss these lymphoid-epithelial lesions of major salivary glands, with emphasis on features that help in the differential diagnosis. Entities discussed include lymphoepithelial sialadenitis, HIV-associated salivary gland disease, extranodal marginal zone B-cell lymphoma, lymphoepithelial carcinoma, lymphadenoma, sebaceous lymphadenocarcinoma, chronic sclerosing sialadenitis, and Warthin tumour.     

Sialolipoma of minor salivary glands

Sialolipoma is a recently described histologic variant of lipoma and is characterized by well-demarcated proliferation of mature adipocytes with secondary entrapment of salivary gland elements. These tumors have been observed in both the major and minor salivary glands, with more than 20 cases being reported in the English literature. In general, the clinical presentation of sialolipomas of the minor salivary glands suggests a diagnostic hypothesis of salivary gland lesions, commonly neoplasms. In the major salivary glands, the clinical features suggest either a salivary gland neoplasm or a lipoma. Surgical excision is the treatment of choice for sialolipomas, with no reports of recurrence or malignant transformation. The present article reports 4 additional cases of sialolipoma, all of them affecting the minor salivary glands, and reviews the literature regarding clinicopathologic aspects, differential diagnosis, and therapeutic management of this recently recognized histologic variant of lipoma.     

Basal cell adenocarcinoma in minor salivary glands

Basal cell adenocarcinoma is a rare and relatively recently characterized malignant salivary gland tumour, the malignant counterpart of basal cell adenoma. Diagnosis depends on finding features similar to adenoma but with an infiltrative growth pattern and exclusion of adenoid cystic carcinoma, sialoblastoma and basaloid squamous carcinoma. Basal cell adenocarcinoma is very rarely reported in minor salivary glands. We report three cases of basal cell adenocarcinoma affecting the labial, buccal and palatal minor salivary glands. One recurred following complete removal but with lesional disruption and further local wide excision appeared curative. A further lesion failed to recur in 5 years' follow-up despite marginal excision and a third after 3 years' follow-up. Basal cell adenocarcinoma is considered a low-grade malignancy, and in the minor glands wide excision and radiotherapy are recommended. However, the reported lesions appear to have a more indolent behaviour than previously reported lesions in minor glands.     

Papillary tumours of the minor salivary glands.

The clinical and histological features of oncocytic adenomatous hyperplasia, papillary adenoma, and papillary adenocarcinoma of the oral cavity are described, and the literature is reviewed. Histological features which may be of value in distinguishing between benign and malignant variants are described, and in view of the slow growth rate of most of these tumours, the importance of long-term follow-up is stressed.     

Clear cell carcinoma of minor salivary glands

Two cases of carcinoma of the minor salivary glands are presented in which most cells had clear cytoplasm. Both patients had clinical histories in excess of 10 years and, in the one case with adequate follow-up, no recurrence had occurred after a further 11 years. Both tumours were locally invasive. The clear cells contained small amounts of glycogen, but no intracytoplasmic mucin. Immunohistochemical and ultrastructural studies showed epithelial features, with no evidence of myoepithelial differentiation. These tumours were very similar to the small number of previously reported cases, which were all considered to be low-grade carcinomas. Amongst the differential diagnoses, the most important is metastatic clear cell carcinoma of the kidney and this can only be confidently excluded clinically or by the use of imaging techniques. In summary, we consider intraoral clear cell carcinoma to be a distinct tumour of low malignant potential.     

Basal cell adenocarcinoma of minor salivary glands

Basal cell adenocarcinoma of minor salivary glands is a relatively rare slow-growing tumor with an infiltrating growth pattern. The infiltrating growth pattern and likelihood of vascular and perineural involvement distinguishes basal cell adenocarcinoma from basal cell adenoma. Other diagnostic considerations include adenoid cystic carcinoma and basaloid squamous carcinoma. Basal cell adenocarcinomas show strong immunoreactivity to cytokeratin 7 and variable myoepithelial staining with S100. It is necessary to differentiate basal cell adenocarcinoma from other basaloid cell tumors of the minor salivary glands because of the prognosis and potential differences in treatment, particularly adenoid cystic adenocarcinoma and basaloid squamous carcinoma. Surgical excision with a wide margin to ensure complete removal has been suggested as the primary treatment for basal cell adenocarcinoma. Radiotherapy has been proposed for lesions in the minor salivary glands because of the higher likelihood of vascular and neural invasion and for those that are diffusely infiltrative.     

Acinic cell carcinoma of minor salivary glands

Three cases of acinic cell carcinoma of minor salivary glands, located respectively in the larynx, base of the tongue, and right tonsil, were encountered at the Section of Pathology of the ENT Department of the University of Padua between 1974 and 1978. Such neoplasms arising in minor salivary gland tissue are extremely rare, but may be found in all sites containing normal or aberrant salivary gland tissue. The histological and histochemical characteristics of the tumour are discussed together with the differential diagnosis from other neoplasms, particularly clear-celled tumours such as glycogen rich adenocarcinoma, mucoepidermoid carcinoma, metastatic clear cell renal adenocarcinoma and clear cell squamous carcinoma. In general, acinic cell carcinoma can be defined as a tumour of low-grade malignancy, though not too rarely it may recur and occasionally metastasize.     

Multifocal canalicular adenoma of the minor labial salivary glands

Canalicular adenoma (CA) is an uncommon benign neoplasia of salivary glands which is clinically difficult to recognise. Despite having an excellent prognosis, the histological diagnosis and clinical management of this entity can be troublesome. While the main differential diagnosis to consider is basal cell adenoma (BCA), similar histological patterns and multifocality have been observed in adenoid cystic carcinoma (ACC) and polymorphous low-grade adenocarcinoma (PLGA), both locally-aggressive malignancies which require radically different treatment to CA. An emphasis has been placed on the value of immunohistochemistry in avoiding diagnostic and surgical errors. CA is positive for AE1/AE3, CD117 and S-100 protein, and negative for p63, α-SMA, Ki 67 and vimentin. Here we discuss the case of a 61-year-old female with CA in her right upper lip, showing multifocal growth histologically. The differential diagnosis with other adenomas is discussed in addition to the role of immunohistochemical studies that can confirm the clinical and surgical findings.     

Electron microscopic immunogold localization of statherin in human minor salivary glands

In this study, which supplements a recent article on the localization of statherin in human major salivary glands, we investigated the intracellular distribution of this peptide in minor salivary glands by immunogold cytochemistry at the electron microscopy level. In the lingual serous glands of von Ebner, gold particles were found in serous granules of all secreting cells, indicating that statherin is released through granule exocytosis. In buccal and labial glands, mostly composed of mucous tubuli, statherin reactivity was detected in the serous element, which represents only a small population of the glandular parenchyma. In these serous cells, however, statherin labeling was absent in secretory granules and restricted to small cytoplasmic vesicles near or partially fused with granules. Vesicle labeling could be related to the occurrence of an alternative secretory pathway for statherin in buccal and labial glands.     

Oncocytic hyperplasia in the human minor salivary glands: A post-mortem study

Oncocytic hyperplasia in the human labial salivary glands was sought in a series of 217 post-mortem subjects. Oncocytic change occured in 183 subjects and hyperplasia was found in 19 of those (the overall incidence being 8.8%), ranging in age from the third deacde to the ninth. The sex distribution showed a significantly greater rate in males (16 of 139 males, 11.5%; 3 of 78 females, 3.8%). Oncocytic hyperplasia occurred in the duct system, and not in the acinar regions; it was frequently seen in the interlobular and intralobular ducts. Oncocytic hyperplasia was classified into four types; focal hyperplasia of the duct wall resulting in partial thickening of the duct wall; marked hyperplasia resulting in thickening of the duct wall, extending over half of the circumference; marked hyperplasia extending to the whole duct wall and intralobular adeno-tubular hyperplasia with or without cystic dilatation. About half of the subjects with oncocytic hyperplasia showed a few hyperplastic foci in one gland. The changes increased in severity in older subjects.     

Immunoreactive prolactin in lesions and tumours of salivary glands

The prolactin binding in obstructive lesions and tumours of salivary glands was described by use of the immunohistochemical PAP technique. Normal salivary glands had prolactin binding cells in the striated ducts only. Chronic obstructive lesions of submandibular glands showed negative immunoreaction for prolactin binding in ductal cells, but positive staining of the luminal surface of ductal segments. In pleomorphic adenomas, occasional neoplastic cells located along the luminal borders of tubular, ductal, or of duct-like epithelial structures were strongly reactive with anti-prolactin and 26.5% of cases pleomorphic adenoma were positive for anti-prolactin. Adenoid cystic carcinoma exhibited positive prolactin binding on the luminal surface of some of tumour foci, but not in the rest of the tumour. Warthin's tumour was devoid of detectable prolactin binding.     

Apoptosis and apoptotic-related factors in mucoepidermoid carcinoma of the oral minor salivary glands

The oncoproteins Bcl-2 and Bax, the tumor suppressor gene product p53, TUNEL (TdT [terminal deoxynucleotidyl transferase] dUTP nick end-labeling) and the cell-cycle antigen Ki-67 were studied in 71 cases of mucoepidermoid carcinoma originating in the oral minor salivary glands. Grade I tumors had higher expression of Bcl-2 than Grade II and III tumors (chi2 test, 0.01相似文献   

Cytokine profile in minor salivary glands from patients with bronchial asthma

BACKGROUND: T lymphocytes are important components of the bronchial inflammatory cell infiltrate in asthma. Because lymphocytes activated in the respiratory tract recirculate to remote glandular and mucosal sites, we previously studied the histologic features of minor salivary glands (MSGs) in bronchial asthma and found an airway-like inflammation with T-lymphocyte infiltration, the presence of mast cells that were often degranulated, and basement membrane thickening but no eosinophil infiltration. OBJECTIVE: We sought to investigate the cellular infiltration and cytokine profile in MSGs from untreated asthmatic subjects, steroid-treated asthmatic subjects, and control subjects and to compare these values with those found in bronchial biopsy specimens. METHODS: The cellular infiltration was studied by using immunohistochemistry. Cytokine messenger (m)RNA expression for IL-4, IL-5, and IFN-gamma was determined by using in situ hybridization and cytokine immunoreactivity with immunohistochemistry. RESULTS: A significant increase in CD4 and IL-4 mRNA(+) cells was observed in MSGs from asthmatic patients (both untreated and steroid-treated subjects) when compared with control subjects, which correlated with the clinical severity of asthma (FEV(1) and Aas score). In contrast to the bronchi, no IL-5 mRNA expression was observed in MSGs, and no difference was observed for MSG IFN-gamma mRNA between the groups. At the level of MSG protein expression, the 3 cytokines were seen, with a significant increase in IL-4 protein expression in steroid-treated asthmatic subjects compared with untreated asthmatic subjects and control subjects, but there were no differences between the groups in IL-5 and IFN-gamma protein expression. CONCLUSION: The cytokine mRNA expression pattern observed in the MSGs of asthmatic subjects was different from that found in the bronchi, suggesting a different local immune regulation.     

Detection of minor salivary glands affected in Sjogren's syndrome by Raman spectroscopy

Sjogren's syndrome(SS) is defined as a slowly processing autoimmune inflammatory exocrinopathy affecting the salivary and lachrymal glands. Due to the difficulty in reaching a diagnosis in some SS cases, there are many criteria published for classification and diagnosis. Among the most of criteria, lip biopsy plays an important role in clinical diagnosis, but it is an invasive and complex method which always causes patients' pain and discomfort. Raman spectroscopy is a noninvasive and real-time vibrational spectroscopic technique applied in the clinical detection and diagnosis of diseases. The diagnostic sensitivity and specificity are both high. The hypothesis is to detect the minor salivary glands affected in SS by the noninvasive Raman spectroscopy instead of lip biopsy. Therefore, Raman spectroscopy may increase the diagnostic sensitivity and specificity, meanwhile prevent patients from pain caused by biopsy.