Rhinosporidiosis of the parotid duct presenting as a parotid duct cyst - a report of three cases

Rhinosporidiosis is a chronic granulomatous infection caused by Rhinosporidium seeberi. Rhinosporidiosis has been reported from many countries but is endemic in certain parts of India and Sri Lanka. The common sites of involvement are the nose and nasopharynx followed by ocular tissue. Rhinosporidiosis is also known to involve many rare sites and may become disseminated to occur in a generalized form. Rhinosporidiosis of the parotid duct is rare and only five reported cases could be found in the literature. We report three cases of rhinosporidiosis of parotid duct presenting clinically as a parotid duct cyst. Rhinosporidiosis was diagnosed by histopathology. None of these patients had rhinosporidiosis at any other site.     

Salivary duct carcinoma in situ of the parotid gland

Aims: To describe three cases of purely in situ salivary duct carcinoma, so as better to define the entity. Methods and results: Three primary tumours of the parotid gland are presented, in each case composed of cysts and ducts and lined by high nuclear grade epithelial cells. All parts of each tumour were surrounded by a myoepithelial cell rim and there was no evidence of invasion. The tumour cells expressed immunohistochemical markers seen in invasive salivary duct carcinoma of usual (high‐grade) type. In two cases the androgen receptor (AR) reaction was strong, but there was no immunohistochemical expression of HER2 protein or gene amplification by in situ hybridization. In the remaining case, fewer nuclei stained for AR, but both HER2 protein and gene amplification were demonstrated. Conclusions: Salivary duct carcinoma in situ is morphologically similar to breast ductal carcinoma in situ and, although our cases are few, salivary duct carcinoma in situ can possibly be subdivided into luminal and non‐luminal cell types, as can analogous mammary neoplasms. The present study cannot determine whether low‐grade cribriform cystadenocarcinoma, architecturally similar but immunohistochemically different, is part of the spectrum of salivary duct carcinoma in situ, or whether it represents a separate entity.     

Aggressive invasive micropapillary salivary duct carcinoma of the parotid gland

The presence of invasive micropapillary component has been reported to be associated with salivary duct carcinoma and poor outcomes. Herein is described a rare case of invasive micropapillary salivary duct carcinoma of the parotid gland in a 60-year-old man. The micropapillary component was approximately 70% of the area of the tumor. Squamous differentiation was focally seen adjacent to the micropapillary component. On immunohistochemistry the ordinary salivary duct carcinoma component was positive for gross cystic disease fluid protein-15 (GCDFP-15), androgen receptor (AR), and HER2/neu, whereas both micropapillary and squamous components were negative for GCDFP-15 and AR. Immunohistochemical staining for D2-40 highlighted the lymph vessel invasion of tumor cells. This patient developed metastases in the lymph nodes of the neck, and also in the liver, lung, and brain. The lymph nodes and liver metastases had both ordinary salivary duct carcinoma and micropapillary components. The patient died of tumor 11 months after the initial surgical operation. The results support that the presence of micropapillary component is associated with more aggressive behavior of salivary duct carcinoma. It is also important for pathologists to recognize that GCDFP-15 and AR expression can be reduced in micropapillary carcinoma in the differential diagnosis of metastatic tumor.     

Surgical anatomy of the parotid duct with emphasis on the major tributaries forming the duct and the relationship of the facial nerve to the duct

Although there is a great amount in the literature to describe the anatomy of the parotid gland as a whole, little attention is given to the parotid duct. The purpose of this study is to examine the surgical anatomy of the parotid duct with special emphasis placed on the major tributaries forming the parotid duct and the relationship of the facial nerve to the duct. Twenty-nine fresh cadaver halves were dissected and the branching pattern of the ducts, position within the parotid, and their relationship to the facial nerve were studied. Of the complete heads studied, the parotid duct had the same pattern in 78.6% on the right and left sides. The parotid ducts in 31.0% of the half heads presented as a single discernible duct from parotid papilla to within the gland. In 62.1% of the half heads, the ducts were formed by a branching pattern within the gland. In the ducts with a branching pattern, 48.3% displayed a bifurcated pattern, 6.9% were trifurcated, and 6.9% had multiple branches. In 6.9% of the half heads studied, the parotid ducts bifurcated distal to the parotid gland. In all cases, the deep lobe of the parotid enveloped the parotid duct; only small ductules connected the superficial lobe with the duct. The facial nerve and its branches were always observed lateral to the parotid duct. Because one dissects lateral to the facial nerve during a superficial parotidectomy, generally the parotid duct remains intact and potential complications such as facial paralysis, sialoceles, and fistulizations are thereby minimized.     

Rhinosporidiosis of the parotid duct cyst: cytomorphological diagnosis of an unusual extranasal presentation

This cytology report highlights a case of rhinosporidiosis of the parotid duct cyst not associated with nasal manifestations. In an endemic area, one should be familiar with its morphologic features in fine-needle aspiration cytology even on scanty material, for it could be one of the investigations in the initial workup of a case.     

Melanocytes in the human parotid gland

A review of the literature yields about 20 reported cases of purportedly primary malignant melanoma of the parotid gland, but no convincing examples of pre-existent melanocytes in the salivary glands. The present paper reports the existence of melanocytes In the interlobular duct of the parotid gland observed during an autopsy case of a Japanese male. Melanocytes with long cytoplasmic processes were distributed in the basal and suprabasal layers of hyperplastic duct epithelium, and melanin granules were sparsely scattered in the duct epithelial cells. This is the first report of melanocytes in the human salivary gland.     

Origin of acinar cell regeneration after atrophy of the rat parotid induced by duct obstruction

Acinar cell regeneration in the rat parotid gland after atrophy induced by a one week period of duct obstruction was examined using histology, immunohistochemistry and transmission electron microscopy (TEM). For immunohistochemistry, antibodies to 5-bromo-2'-deoxyuridine (BrdU), injected one hour before tissue collection, and cytokeratin were employed. When clips were removed from the duct, only ductal epithelial cells remained; all acinar cells had been deleted. Some duct cells were BrdU positive. After three days, newly-formed acini comprising immature acinar cells had appeared; many of the cells were BrdU positive and mitotic figures were readily identified. Thereafter progressive acinar cell maturation and proliferation occurred, parotid gland weight returning to control levels by 7 days. Peak BrdU labelling indices for duct and acinar cells were on days 0 and 4, respectively. By TEM, cytoplasmic organelles in epithelial cells of transitional duct-acinar structures seen at 2 days were poorly developed. Immature acinar cells seen on day 3 contained zymogen granules and had increased endoplasmic reticulum and mitochondria. By day 5, maturing acinar cells had abundant endoplasmic reticulum and zymogen granules, resembling acinar cells in control glands. These observations indicated origin of acinar cell precursors from duct cells during regeneration of the acinar cell-free atrophic gland. Subsequent expansion of the acinar cell population was dependent on maturation and proliferation of these newly-formed cells.     

Incidence and histology of human accessory parotid glands

The parotid glands of 228 Japanese human cadavers were examined to determine the incidence and histological features of accessory parotid glands. The incidence was found to be 56% with no differences between right and left sides or between sexes. Thirty parotid glands and their associated accessory glands were examined histologically: eight of these accessory glands were found to be mixed secretory glands (i.e., containing both serous and mucous acini). Thus, the pattern of differentiation of a significant fraction of accessory glands differs from that of the main parotid gland: it appears that mixed acini, present in the early stages of development, persist into later life, and their presence may be related to tumors developing at these sites. © 1993 Wiley-Liss, Inc.     

Antimicrobial mechanisms of the urinary tract

The urinary tract is a key system to maintain the homeostasis of the human body. It is relatively open to the outside environment, the perineum, a region highly colonized by bacteria. Bacteria can even be found in urine of healthy individuals. Still, urinary tract infections are far less frequent than it could be expected under these conditions. The high resistance against such infections has been observed already more than 100 years ago. Since then, many antimicrobial mechanisms of the urinary tract have been elucidated. Some questions, however, remain challenges for patients, scientists and health care professionals. In this review, we try to summarize the achieved knowledge about mechanisms, maintaining the urinary tract free of infection. In addition, we discuss their relevance and possible clinical application.     

Electrophoretic analysis of rat parotid salivary protein composition: investigation of the parasympathetic atropine-resistant secretion

Rats pretreated with atropine and adrenoceptor antagonists show secretion of saliva upon electrical stimulation of the parasympathetic nerve of the parotid gland. The protein composition of this secretion has been analysed by sodium dodecyl sulphate–polyacrylamide gel electrophoresis (SDS–PAGE) and compared with the protein profiles obtained with secretions evoked by parasympathetic stimulation (in the absence of atropine) or infusion of bethanechol with or without vasoactive intestinal peptide (VIP, a probable transmitter conveying parasympathetic secretory impulses). The SDS–PAGE patterns were highly reproducible for an individual rat although minor differences were detected between different rats. The method requires only microlitre volumes of unconcentrated rat saliva and thus is ideal for monitoring sequential aliquots collected from the same rat. The SDS–PAGE patterns indicated (i) little change in the protein profile during prolonged stimulation, (ii) a similar profile with parasympathetic stimulation or infusion of bethanechol, and (iii) a quantitative, rather than qualitative, response to administration of atropine (during parasympathetic stimulation) or VIP (during bethanechol infusion). Thus, the salivary protein composition associated with non-adrenergic, non-cholinergic (NANC) secretion appears similar to that evoked in response to parasympathetic nerve stimulation in the absence of muscarinic receptor blockade.     

Morphological and functional changes of the rat parotid glandular cells by clipping and reopening the parotid duct, using ham8 antibody

The purpose of this experiment is to examine the proliferative process of rat acinar cells after parotid duct ligation and reopening. Two experimental groups were observed. The first group was killed from 0 to 14 days after the duct ligation. In the second group, the duct was clipped for 14 days, and it was reopened. Following a period of from 2 to 28 days after removal of the clip, the glands were removed to perform a histological analysis, including hematoxylin-eosin (HE), immunofluorescent staining using HAM8 antibody, which recognizes connexin 32, and transmission electron microscopy (TEM). In the experimental gland from the 1st group at 6 days after ligation (I-6D), the acinar cells disappeared. In the tissue from the 2nd group 8 days after reopening (II-8D), newly formed acinar cells were found again. Lobular structure of the parotid glands recovered in the II-21D. HAM8 signals were observed between normal acinar cells, while they declined in the tissue from I-1D, and they were not observed in the I-2D. HAM8 signals were first observed in the II-25D and then subsequently returned to normal levels in the II-28D. These results suggest that the intercellular communication and functional recovery was not complete 25 days after reopening of the duct.In conclusion, the recovery of the acinar structure was recognized during an extended period of duct ligation, however, a time lag between the morphological and functional recovery was found to exist.     

Quantification of IgA and IgG and specificities of antibodies to viral proteins in parotid saliva at different stages of HIV-1 infection

Paired sera and parotid saliva from 75 HIV-1-infected patients, divided in three equal groups with CD4⁺ cell counts > 500, 200–500 and < 200/mm³, respectively, were analysed for IgG, IgA and secretory IgA (sIgA) concentrations and for IgG and IgA antibody directed to HIV-1. Twenty-nine age-matched HIV⁻ subjects were used as controls. In serum the concentrations of immunoglobulins were significantly increased in HIV-infected subjects compared with controls, and a progressive increase of IgA and sIgA was noticed while the CD4⁺ cell count decreased. In contrast, concentrations of IgA and sIgA were not different in parotid saliva between the four subject groups. By an ELISA test directed towards HIV-1 proteins, 73 of the 75 serum specimens from the HIV-infected subjects (97%) and 43 of the corresponding saliva (57%) were found positive for specific IgA antibodies to HIV-1, with an even distribution among the three groups of patients. By Western blotting multiple specificities of IgA to HIV-1 proteins were not frequently found in patients. By contrast, in spite of an IgG concentration in saliva about 100 times lower than that of IgA, reactivities were significantly higher for IgG than for IgA antibodies, especially to env and to pol HIV-1 products. Altogether, these data suggest that the regulation of IgA production in HIV-infected subjects is independent in serum and in parotid saliva. This imbalance of IgA/IgG antibodies to HIV-1 at the mucosal level appears to be a specific feature of HIV-1 infection, and may raise important issues in terms of local protection after immunization.     

Subcellular distribution of melatonin receptors in human parotid glands

The hormone melatonin influences oral health through a variety of actions, such as anti‐inflammatory, anti‐oxidant, immunomodulatory and antitumour. Many of these melatonin functions are mediated by a family of membrane receptors expressed in the oral epithelium and salivary glands. Using immunoblotting and immunohistochemistry, recent studies have shown that the melatonin membrane receptors, MT1 and MT2, are present in rat and human salivary glands. To date, no investigation has dealt with the ultrastructural distribution of the melatonin receptors. This was the aim of the present study, using the immunogold method applied to the human parotid gland. Reactivity to MT1 and, with less intensity, to MT2 appeared in the secretory granules of acinar cells and in the cytoplasmic vesicles of both acinar and ductal cells. Plasma membranes were also stained, albeit slightly. The peculiar intracytoplasmic distribution of these receptors may indicate that there is an uptake/transport system for melatonin from the circulation into the saliva.     

Morphological study of the fetal parotid duct and buccinator muscle and the relationship to salivary secretion

The parotid glands secrete about 25% of all saliva produced. In the presence of a stimulus, the amount of saliva secreted from the parotid gland increases to 50%. A decrease in the amount of produced saliva due to aging and parotiditis results in a dry mouth. Therefore, the parotid duct is important to maintaining a healthy oral cavity. In human adults, the parotid duct, ～6–8‐cm long, travels over the masseter muscle and penetrates the buccinator muscle to enter the oral cavity. Although there have been various studies regarding the parotid gland, only few suggest a functional role of the parotid duct, especially its area of penetration of the buccinator muscle. In this study, 34 fetal specimens ranging from 4 to 10 months of age at death were dissected for anatomical and histological examinations. The area of the parotid duct penetrating the buccinator muscle was fully formed in 5‐month‐old fetuses. This study found buccinator muscle fibers invading the parotid duct wall near its opening in 6‐month‐old fetuses and older. Our results support the claim that the buccinator muscle may act as a sphincter, playing a role in regulating and possibly preventing the reflux of salivary secretions into the parotid duct. Clin. Anat. 23:642–648, 2010. © 2010 Wiley‐Liss, Inc.     

Increased release of tissue plasminogen activator and its inhibitor in human parotid saliva upon stimulation

Parotid saliva from 12 healthy volunteers was collected prior to and after 5 and 25 min of stimulation at a constant flow rate of 0.25 or 1.0 ml min^-1. In the salivary samples the concentrations of tPA (tissue-type plasminogen activator), PAI-1 (plasminogen activator inhibitor type-1), albumin and total protein were determined and the activity of amylase, tPA and PAI assessed. Presence of both tPA and PAI-1 antigen was demonstrated in all samples, and in unstimulated saliva the ratio between the activator and its inhibitor was 1:7. Upon stimulation we found a significantly increased concentration of PAI-1, a less pronounced increase in tPA concentration, unchanged amylase and total protein levels and significantly decreased albumin concentration. tPA activity was significantly reduced after prolonged stimulation which had no effect on PAI activity. In stimulated saliva a significant positive correlation between concentration of tPA and PAI-1 was demonstrated. Stimulation with citric acid had no effect on output of albumin which is passively filtered from blood, whereas the increase in flow rate corresponded to the significantly increased secretion rate of total protein and amylase which is secreted by gland cells. The secretion pattern of tPA and PAI-1 differed significantly from that of albumin in showing markedly increased output rate during the stimulation period, and the relative increase in output of PAI-1 was significantly higher than that of amylase and total protein. Thus, the results from this study suggest an active release of both tPA and its main inhibitor PAI-1 into saliva.     

感染HCMV的腮腺导管上皮细胞CK和EMA丢失

目的 研究人类巨细胞病毒(HCMV)感染对腮腺导管上皮细胞表型产生的影响。方法 用免疫组化方法检测腮腺巨细胞包涵体病石蜡包埋组织中巨细胞病毒以及早期抗原、CK、EMA等的表达．结果 腮腺导管上皮细胞感染人巨细胞病毒后，作为上皮性标志物的CK和EMA表达呈阴性。结论 人巨细胞病毒感染腮腺导管上皮细胞使其CK和EMA丢失。单层上皮角蛋白网具有维持上皮细胞机械力学完整性的功能。