Inverted ductal papilloma: a distinctive lesion of minor salivary gland

Analysis of the Clinical Relevance of Histological Classification of Benign Epithelial Salivary Gland Tumours

INTRODUCTION

A vast increase in knowledge of numerous aspects of malignant salivary gland tumours has emerged during the last decade and, for several reasons, this has not been the case in benign epithelial salivary gland tumours. We have performed a literature review to investigate whether an accurate histological diagnosis of the 11 different types of benign epithelial salivary gland tumours is correlated to any differences in their clinical behaviour.

METHODS

A search was performed for histological classifications, recurrence rates and risks for malignant transformation, treatment modalities, and prognosis of these tumours. The search was performed primarily through PubMed, Google Scholar, and all versions of WHO classifications since 1972, as well as numerous textbooks on salivary gland tumours/head and neck/pathology/oncology. A large number of archival salivary tumours were also reviewed histologically.

RESULTS

Pleomorphic adenomas carry a considerable risk (5-15%) for malignant transformation but, albeit to a much lesser degree, so do basal cell adenomas and Warthin tumours, while the other eight types virtually never develop into malignancy. Pleomorphic adenoma has a rather high risk for recurrence while recurrence occurs only occasionally in sialadenoma papilliferum, oncocytoma, canalicular adenoma, myoepithelioma and the membranous type of basal cell adenoma. Papillomas, lymphadenoma, sebaceous adenoma, cystadenoma, basal cell adenoma (solid, trabecular and tubular subtypes) very rarely, if ever, recur.

CONCLUSIONS

A correct histopathological diagnosis of these tumours is necessary due to (1) preventing confusion with malignant salivary gland tumours; (2) only one (pleomorphic adenoma) has a considerable risk for malignant transformation, but all four histological types of basal cell adenoma can occasionally develop into malignancy, as does Warthin tumour; (3) sialadenoma papilliferum, oncocytoma, canalicular adenoma, myoepithelioma and Warthin tumour only occasionally recur; while (4) intraductal and inverted papilloma, lymphadenoma, sebaceous adenoma, cystadenoma, basal cell adenoma (apart from the membranous type) virtually never recur. No biomarker was found to be relevant for predicting recurrence or potential malignant development. Guidelines for appropriate treatment strategies are given.

An Interesting Case of Oral Inverted Ductal Papilloma

Ductal papillomas are rare benign papillary tumours of the minor salivary glands. Previously they have been classified into three subtypes: inverted ductal papilloma (IDP), sialadenoma papilliferum and intraductal papilloma. The oral inverted ductal papilloma is the least common of these lesions, with 48 cases reported to date in a search of the English-language literature. We describe an interesting case of oral IDP and highlight the pertinent clinical and histopathological features. Importantly, unlike the histologically similar inverted papilloma (IP) of the nose and paranasal sinuses, oral IDP is a completely benign lesion and is not associated with malignant change. Clinical relevance: This case report aims to raise awareness of the lesion, oral inverted ductal papilloma (IDP). We outline the clinical features and unique histopathology of oral IDP so that clinicians may correctly diagnose such a lesion and implement appropriate treatment.

Inverted ductal papilloma of the oral cavity secondary to lower lip trauma. A case report and literature review

Inverted ductal papilloma of the oral cavity is an infrequent benign neoplasm of papillary appearance that originates in the secretory duct of a salivary gland. The etiology is unknown, though some authors have related it to human papillomavirus (HPV) infection. We present the case of a 40-year-old woman with a tumor of the lower lip mucosa. Histopathological study of the lesion diagnosed inverted ductal papilloma of the oral cavity. Human papillomavirus DNA detection and typing based on tumor lesion DNA amplification and posterior hybridization, revealed no presence of viral DNA. The antecedents of trauma reported by the patient could have played an important role in the development of this tumor.

Key words:Inverted ductal papilloma, intraductal papilloma, oral papilloma, papillary epidermoid adenoma.

Oral inverted ductal papilloma associated with condyloma acuminata and HPV in an HIV+ patient

Oral inverted ductal papillomas are rare benign tumours of minor salivary glands. A case that appeared in a middle-aged HIV+ woman simultaneous to two condyloma acuminata on the lips is described. The presence of human papilloma virus (HPV) 11 DNA was demonstrated in all the samples using polymerase chain reaction. HPV could play an important role in the aetiology and pathogenesis of these lesions in this patient.

Inverted ductal papilloma of minor salivary gland: Case report with immunohistochemical study and literature review

Inverted ductal papilloma (IDP) is a type of ductal papilloma arising in ducts of minor salivary glands. Very few cases, and no cases in Japan, have been reported. Reported herein is a case of IDP with a review of the literature. The patient was a 49-year-old man presenting with a lump in the right buccal mucosa of the premolar area of the mandible. The tumor was excised en bloc after a biopsy diagnosis of IDP. On the surface of the covering epithelium, an opening was seen to be filled with mucinous material. On cut surface the opening led to the tumor cavity. The major portion of the tumor parenchyma was made up of papillary proliferation of basaloid squamous cells. Some crypts, microcysts, and mucous cells were seen. There were no findings suggestive of a malignant tumor. The patient's postoperative course was uneventful and there has been no recurrence after 1 year's follow up. Immunohistochemical analysis of the present case supports the hypothesis that IDP originates from squamous metaplasia and proliferation of minor salivary gland duct cells.

Detection of human papillomavirus DNA in oral inverted ductal papillomas

AIMS

To determine the presence or absence of human papillomavirus (HPV) DNA in oral inverted ductal papillomas (IDPs) using in situ hybridisation (ISH), and to analyse all cases for histological features of HPV infection.

METHODS

Six cases were retrieved from archival material and paraffin wax blocks were submitted for the detection of HPV DNA by means of ISH. A wide spectrum probe for HPV subtypes 6, 11, 16, 18, 31, 33, 45, 51, and 52 was used initially. Cases that were positive using this wide spectrum probe were further subtyped using HPV type specific probes (6/11, 16/18, and 31/33). The histological features of all tumours were analysed using routine microscopy.

RESULTS

Of the six cases of oral IDP identified, three were positive for HPV subtypes 6/11. All positive cases showed histological features of HPV infection (koilocytosis, papillomatosis, binucleated keratinocytes, and abnormal mitosis) in both the surface and the inverted epithelium. The three cases that tested negative for HPV DNA also exhibited focal histological features of HPV infection (two in the surface epithelium and one in the endophytic epithelium).

CONCLUSIONS

These are the first documented cases of oral IDP to demonstrate positivity for HPV DNA and also to show histological features of HPV infection.

Ductal papillomas of salivary gland origin: A report of 19 cases and a review of the literature

The term ductal papilloma is used to identify a group of 3 rare benign papillary salivary gland tumors known as inverted ductal papilloma, sialadenoma papilliferum, and intraductal papilloma. They represent adenomas with unique papillary features and arise from the salivary gland duct system. We describe the clinical and microscopic features of 19 new cases of ductal papillomas and combine them with 116 cases previously published in the English-language medical literature. These 19 cases were composed of 13 inverted ductal papillomas, 3 sialadenoma papilliferums, and 3 intraductal papillomas. Collectively, these 19 ductal papillomas occurred most commonly in the sixth to eighth decade of life, with an average patient age of 54 years. Men predominated 1.37:1. The sialadenoma papilliferums presented as papillary lesions clinically with all 3 misinterpreted as squamous papillomas by the surgeons. The inverted ductal papillomas and intraductal papillomas appeared as submucosal nodules. The lip and the palate were the most common locations for inverted ductal papilloma and sialadenoma papilliferum, respectively. The sites for the 3 intraductal papillomas were the parotid papilla of the Stensen's duct, the upper lip, and the buccal mucosa. With light microscopy, inverted ductal papillomas appeared to arise from the excretory ducts near the mucosal surface, whereas intraductal papillomas appeared to arise from the excretory ducts at a deeper level. Sialadenoma papilliferum had a more complex histology, with a biphasic growth pattern of exophytic papillary and endophytic components. All 19 cases were treated by surgical excision. Follow-up information was available in only 2 cases, both inverted ductal papillomas. Neither case recurred during a 20-year period. Sialadenoma papilliferum, with a literature-derived recurrence rate of 10% to 15%, seems to assert a more significant biological behavior than inverted ductal papilloma and intraductal papilloma. Our findings justify the separation of these 3 entities based on clinical and histologic parameters. They are tumors of adulthood and, in addition, have in common their relationship to the excretory duct system, their anatomical distribution, and their general behavior.

Inverted ductal papilloma of minor salivary gland origin: morphological aspects and cytokeratin expression

Ultrastructural features and cytokeratin expression of inverted ductal papillomas of minor salivary gland origin were studied. Under the electron microscope, an increased number of desmosomes and mucus-like granules in some cells were the most striking features. Immunohistochemical study revealed that tumor cells displayed strongly positive reactions with cytokeratins 13 and 14, and less strong reactions with cytokeratins 7, 8, 18 and 5D3. These results support the hypothesis that an inverted ductal papilloma can be derived from the proximal portion of a salivary gland excretory duct.

Inverted ductal papilloma of minor salivary glands

Inverted ductal papillomas are rare tumours of minor salivary glands. A case is reported on the lower lip of a 50-year-old man. The tumour showed a characteristic endophytic growth pattern and was composed of bulbous papillary projections of basaloid cells dilating and filling the superficial portion of the excretory duct. Histologically, inverted ductal papillomas resemble the inverted papilloma of the nose and paranasal sinuses, but are completely benign and are not associated with malignant change.

The World Health Organization's Histological Classification of Salivary Gland Tumors. A commentary on the second edition

The second edition of the World Health Organization's Histological Classification of Salivary Gland Tumors is more extensive and detailed than the previous edition published 20 years ago. The new edition is based on data regarding newly described tumor entities and the behavior and prognosis of the previously classified tumors. The distinct morphologic features of monomorphic adenomas justify their separation for purposes of identification. Among the carcinomas, various types were distinguished for purposes of recognition, prognosis, and treatment. The term tumor was replaced by carcinoma in the following two entities: acinic cell carcinoma and mucoepidermoid carcinoma. The tumor-like lesions were described in more detail.

Squamous cell carcinoma in an inverted papilloma of the buccal mucosa

Inverted papillomas of the oral cavity are rare lesions. Although in the seven oral cases previously reported the lesions were benign, approximately 10% to 15% of inverted papillomas of the nasal cavity and paranasal sinuses develop or are associated with squamous cell carcinoma. This report presents a case of squamous cell carcinoma arising in an inverted papilloma of the buccal mucosa. Histologically, this lesion demonstrated the morphologic features of inverted papilloma in the superficial portion, and squamous carcinoma in deeper sections. This case suggests that although rare, inverted papillomas of the oral cavity should be considered potentially malignant or capable of harboring a malignancy.

Oral monomorphic adenomas

Monomorphic adenomas of the oral cavity have a predilection for the anterior mouth, particularly the upper lip. Two of the monomorphic adenomas, the inverted ductal papilloma and the canalicular adenoma, are biologically benign, but unfamiliarity with their histopathologic appearance can lead to a misdiagnosis of malignancy. The clinical and pathologic features of each are presented.

WHO International Histological Classification of Tumours. Tentative Histological Classification of Salivary Gland Tumours

The principles of the proposed modified WHO Histological Typing of Salivary Gland Tumours are based on the following: 1) The classification of tumours is oriented to the routine work of the practicing surgical pathologists, those who do not see tumours of the salivary glands very often. The inclusion of rare, but clearly defined tumour entities should be helpful to surgical pathologists consulting with clinical specialists. 2) The different types of carcinomas must be distinguished not only by precise histopathological definitions, but also considering differences in prognosis and treatment. For example, the polymorphous low-grade adenocarcinoma and the epithelial-myoepithelial carcinoma are characterized by a relatively good prognosis in contrast to the salivary duct carcinoma. 3) Special points of discussion are: subclassification and grading of carcinomas (e.g. acinic cell carcinoma, mucoepidermoid carcinoma and adenoid cystic carcinoma), the classification of basal cell tumours (basal cell adenoma, basal cell carcinoma, solid type of adenoid cystic carcinoma), malignant tumours in pleomorphic adenomas and the differential diagnosis between primary tumours and metastases.

Sialadenoma papilliferum

Sialadenoma papilliferum is a tumor of salivary tissues that has considerable histologic and biologic similarities to analogous tumors of the eccrine apparatus of the skin. Thus far found only at intraoral and parotid gland sites, sialadenoma papilliferum usually has the clinical course of a benign, locally significant lesion.

Oral inverted ductal papilloma

A case of oral inverted ductal papilloma that appeared on the lower lip of a 44-year-old man is described. A literature review and discussion of the histopathologic features and histogenesis of this uncommon lesion of minor salivary gland origin are also presented.

Minor salivary gland tumors. A histologic and immunohistochemical study

Clinical, histologic, and immunohistochemical data were reviewed and evaluated on 238 oral minor salivary gland tumors. Benign neoplasms accounted for 65% of the total. Pleomorphic adenomas were the most common of all neoplasms, and mucoepidermoid carcinomas were the most frequently encountered malignancies. Pleomorphic adenomas and adenoid cystic carcinomas stained positive for S-100 protein. Immunohistochemistry was believed to be of potential assistance in diagnosis of salivary gland tumors and in prediction of histogenesis.

Sialoadenoma papilliferum

2 additional examples of sialoadenoma papilliferum, one occurring in the palate of a 32-year-old woman and the other in the palate of a 43-year-old man, have been added to the previously reported 11 cases. 9 of the 13 reported cases occurred in the palate with a 5.5:1 prevalence in men. The age at discovery ranged from 32 to 77 years. Whether these lesions represent a benign salivary gland tumor or hyperplasia of duct epithelium remains debatable. Surgical excision apparently effects a cure as no recurrences have been reported.

The pathology of head and neck tumors: papillomas of the upper aerodigestive tracts, Part 18

The human papillomavirus class of DNA viruses are more than circumstantially related to oral and airway papillomas. Whether they are fully oncogenic, in the malignant sense, without other agents is questionable. Recent advances in molecular virology and the use of genus-specific (common) antigen-antibody reactions have identified papillomavirus in laryngeal and oral papillomas. Laryngeal and oral papillomas could be precancerous lesions, but they show a low-risk and long-time interval leading to malignancy unless significant iatrogenic or host variables--such as radiotherapy or immuno-incompetence--are added. Two different papillomas in the larynx can be recognized; a nonkeratinizing, papillomavirus-related lesion, and a keratinizing, usually solitary papilloma, which may or may not be related to a virus genesis and may be equated with a keratosis or clinical leukoplakia.