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

Sialadenoma papilliferum-like intraductal papillary tumor with unveiling BRAF V600E and PIK3CA H1047R mutations: Case report with molecular analysis and literature review

INTRODUCTION

Sialadenoma papilliferum (SP), a rare minor salivary gland tumor, shares morphological and genetic similarities with syringocystadenoma papilliferum. Recent studies have identified BRAF V600E or HRAS mutations in SP, suggesting its neoplastic nature. Despite being uncommon, SP poses diagnostic challenges due to its resemblance to other lesions like squamous papilloma. The emergence of sialadenoma papilliferum-like intraductal papillary tumor (SP-IPT) further complicates its classification, emphasizing the need for thorough investigation.

CASE PRESENTATION

A 50-year-old male presented with a left palatal lesion histologically diagnosed as SP-IPT. Surgical resection revealed characteristic features, including papillary projections into cystically dilated ductal spaces. Immunohistochemistry confirmed positivity for pan-keratin AE1/AE3, cytokeratin 7, SOX10, and BRAF V600E. Whole-exome sequencing identified BRAF V600E and PIK3CA H1047R mutations. No recurrence was observed three months post-excision.

DISCUSSION

SP-IPT's diagnostic complexity stems from its resemblance to SP without an exophytic papillary component. However, shared BRAF mutations suggest a close relationship between the two entities. Similarities with skin adnexal tumors underscore the importance of molecular markers in tumor classification. The identification of PIK3CA mutation in SP-IPT adds to its molecular diversity, warranting further investigation into its clinical significance.

CONCLUSION

This study presents a case of SP-IPT with unique histological and molecular features, highlighting its diagnostic and therapeutic challenges. The co-occurrence of BRAF V600E and PIK3CA H1047R mutations suggests a distinct molecular profile in SP-IPT, necessitating further research to elucidate its biological behavior and clinical implications.

Clinicopathologic Study of Sialadenoma Papilliferum of the Minor Salivary Glands: A Series of 8 New Cases With BRAF V600E Mutation-specific Immunohistochemical Analysis

Introduction. Sialadenoma papilliferum (SP) is a rare benign neoplasm that usually arises in the minor salivary glands. Recently, it was demonstrated that SP shares similar molecular genetic alterations (BRAF V600E or HRAS mutations) with its morphologic analog, syringocystadenoma papilliferum. Methods. We sought to perform clinicopathologic and immunophenotypic (BRAF V600E and SOX10) analyses on 8 new cases of SP. Results. The cases were from 4 males and 4 females, with ages ranging from 28 to 81 years (average: 64 years). The common locations were the hard palate (n = 3) and buccal mucosa (n = 3). Histopathologically, 7 cases were classic and 1 case was oncocytic. BRAF V600E immunohistochemistry (IHC) was positive in all classic SP, involving both the exophytic and endophytic components, but negative in the oncocytic SP. SOX10 was positive in the endophytic ductal cells of the evaluated classic SP but was negative in the oncocytic SP. Conclusions. We report 8 new cases of this rare salivary gland neoplasm, using BRAF V600E and SOX10 IHC to further support the following points: (1) the functional role of BRAF V600E mutation, RAS/mitogen-activated protein kinase signaling pathway in the pathogenesis of classic SP of salivary glands by IHC; (2) the analogous relationship between SP, syringocystadenoma papilliferum, and papillary seromucinous adenocarcinoma with sinonasal papilloma-like surface component (PSASP-like surface); (3) endophytic ductal component in classic SP arises from the intercalated ducts and not the excretory ducts; and (4) oncocytic SP is distinct from classic SP.

Sinonasal mixed transitional epithelial-seromucinous papillary glandular neoplasms with BRAF p.V600E mutations - sinonasal analogues to the sialadenoma papilliferum family tumors

Sinonasal non-intestinal type adenocarcinoma (non-ITAC) is a heterogeneous category that may benefit from improved taxonomy. With the recognition that most non-ITAC are phenotypically seromucinous, stratification may be improved by applying salivary type morphologic criteria and molecular findings. We report two cases of papillary seromucinous adenocarcinoma with sinonasal papilloma-like surface components that show histologic and molecular features analogous to the salivary sialadenoma papilliferum family of tumors. Case 1 concerns a 50-year-old female who presented with a left anterior nasoethmoid polyp, while case 2 is that of a 74 year old female with nasal polyposis. Histologically, both cases demonstrated a surface transitional sinonasal papilloma-like component (more prominent in case 2) with a deeper bilayered glandular component showing papillary and tufted micropapillary growth of monomorphic columnar to cuboidal cells with eosinophilic cytoplasm. Case 1 also showed a deep cribriform/microcystic component. Immunostains showed a delimiting p63/p40 positive basal layer around the SOX-10 positive glandular elements, while the transitional sinonasal papilloma-like components were diffusely p63/p40 positive. Like sialadenoma papilliferum and related tumors, both cases demonstrated BRAF p.V600E mutations in both components and no other alterations. The patients remain disease free at 9 and 19 months respectively. Our cases illustrate a novel sinonasal lesion and suggest that improved morphologic and molecular categorization may refine and reduce the category of non-ITAC.

Intraductal papilloma of the sublingual gland imitating a ranula

Ductal papillomas are rare benign lesions of the salivary glands with two distinctive types, intraductal and inverted. The rarest anatomical location where intraductal papillomas occur is the major salivary glands. In the present study, we report an intraductal papilloma of the left sublingual gland with the relevant clinical, imaging, and histopathological findings and postoperative follow-up. To our knowledge, this is the fourth case of an intraductal papilloma of a sublingual gland to be reported in the international literature. We present this rare case because of its clinical and radiological imitation of a ranula.

Sialadenoma papilliferum of a minor salivary gland with transformation to mucoepidermoid carcinoma

Sialadenoma papilliferum (SP) is a rare benign tumor usually occurring in the minor salivary glands. Only two cases of malignant transformation of SP and an occasional case of dysplasia in SP have been reported in the literature till now. We report a case of SP of a minor salivary gland in a middle-aged male where the exophytic component retained the histomorphological features of SP while the endophytic component displayed characteristics of a mucoepidermoid carcinoma. Malignant change in sialadenoma papilliferum is an extremely rare phenomenon that requires further research and documentation. Careful evaluation of morphologic features and reporting of more such cases is required to delineate the clinical behavior of this unusual tumor.

Activating HRAS mutation in a case of inverted ductal papilloma of the salivary gland

Inverted ductal papilloma (IDP) is one of the least common benign papillary/cystic neoplasms of the salivary duct system, being characterized histologically by florid hyperplasia of duct-type epithelial cells into a cystic lumen near the orifice with occasional endophytic growth of the surface squamous epithelium along the terminus of the affected excretory duct. Given its rarity, the exact etiology of IDP remains to be defined. We herein present the first evidence of oncogenic HRAS mutation in a case of oral IDP. This finding, together with the frequent and specific BRAF mutations in sialadenoma papilliferum reported in the recent literature, supports an active role of the MAP-kinase cascade in the pathogenesis of benign papillary neoplasms of terminal duct origin.

Sialadenoma Papilliferum of the Bronchus: An Unrecognized Bronchial Counterpart of the Salivary Gland Tumor With Frequent BRAF V600E Mutations

Sialadenoma papilliferum (SP) is a rare benign tumor of the salivary glands, and only 3 unequivocal cases of SP arising in the bronchus have been reported. We herein describe the histomorphologic and molecular features of 4 bronchial SP cases and discuss the differential diagnosis of this entity and the relationship with its clinicopathologic mimics, in particular, glandular papilloma and mixed squamous cell and glandular papilloma (GP/MP). We encountered 2 male and 2 female patients with bronchial SP (mean: 66.8 y old). All 4 tumors arose in the central bronchus and were characterized by a combination of surface exophytic endobronchial papillary proliferation and a submucosal multicystic component with complex architecture. The neoplastic epithelium consisted predominantly of nonciliated stratified columnar cells with ciliated, squamous, and mucinous cells present focally. While 2 tumors (50%) harbored a BRAF V600E mutation by molecular and immunohistochemical analysis, similar to GP/MP, no KRAS, HRAS, AKT1, or PIK3CA mutations were detected in any of the cases. Two patients were treated with limited resection, while 2 patients underwent lobectomy based on the diagnosis of adenocarcinoma or possible squamous cell carcinoma in situ in the preoperative biopsy. All survived without recurrence or metastasis for 23 to 122 months after treatment. SP can develop in the central bronchus as the bronchial counterpart of the salivary gland tumor and should be considered in the differential diagnosis of endobronchial tumors. In addition, some histologic resemblance and frequent BRAF V600E mutation raise the possibility of SP and GP/MP being on the same disease spectrum.

Sialadenoma papilliferum: clinicopathologic, Immunohistochemical, molecular analyses of new five cases and review of the literature

Background

Sialadenoma papilliferum (SP) is an extremely rare benign neoplasm of salivary glands. To explore and define the clinicopathological features of SP, we retrospectively analyzed 89 cases previously reported and five new cases.

Methods

The clinical features, histopathology, immunohistochemistry and molecular analysis of our cases were further performed and the related literatures were reviewed and analyzed.

Results

Combining 89 cases from the literature with our cases, the hard palate was the most common locations for SP. However, two of our cases were rarely located in the esophageal mucosa. Among all cases, the male gender was more affected, with the average age and median age of 61.8 and 62 years, respectively. Conventional histomorphologically, SP was characterized by complex papillary structures with a biphasic growth pattern of exophytic squamous component and endophytic glandular component. The glandular structures were lined by a double layer of epithelium composed of flattened or cuboidal basal cells and a cuboidal or columnar luminal cells formed papillary infoldings into the ductal lumina. Immunohistochemically, the luminal epithelial configurations showed strong expression of CK7 along the luminal cell membrane, while the basal myoepithelia displayed strong nuclear p63 expression. In both the glandular and squamous tumour components showed BRAF V600E-positive immunostaining and BRAF V600E mutation.

Conclusion

For the first time, we have comprehensively aggregated and analyzed 90 cases sialadenoma papilliferum from almost all previous publications, and further explored the clinicopathological features of SP; concordantly, this study demonstrated that SP shows a papillomatous growth pattern with exophytic and endophytic proliferation of ductal epithelium composed of double-layered cells harboring BRAF V600E mutation. Additionly, adequate treatment for SP is surgical excision, with a favorable prognosis in patients.

Sialadenoma Papilliferum

Sialadenoma papilliferum (SP) is a rare, benign salivary gland neoplasm sharing similar histopathologic features and harboring the same genetic alterations, BRAF V600E or HRAS mutations, with syringocystadenoma papilliferum. SP most commonly occurs in the hard palate and in older adults. Clinically, SP is most likely to be diagnosed as a squamous papilloma. Microscopically, SP shows an exophytic papillary epithelial proliferation and a contiguously endophytic ductal proliferation. Two distinct subtypes are identified: classic SP and oncocytic SP. Conservative surgical treatment seems to be adequate with a low recurrence. SOX10 immunohistochemistry and BRAF analysis may be useful in differential diagnosis.

Papillary Neoplasms of the Salivary Duct System: A Review

Papillary lesions of the salivary duct systems are uncommon. They encompass a heterogeneous group of benign, intermediate, and potentially aggressive neoplasms. With a few exceptions, historical descriptive terms such as papillary adenocarcinoma, papillary cystadenocarcinoma, and papillary adenoma are being replaced by defined entities, at same time acknowledging the papillary features as a histologic pattern. The evolving genetic landscape of these lesions increasingly permits their reproducible categorization. This article discusses those papillary proliferations encountered in the salivary glands with a focus on intraductal papillary mucinous neoplasms and cystadenomas. Intraductal carcinomas and sialadenoma papilliferum are addressed in separate articles in this issue.

A Rare Case of Intraductal Papilloma Arising from Minor Salivary Gland in the Floor of the Mouth

A 77-year-old woman with a rare oral intraductal papilloma arising from the minor salivary gland located on the floor of the mouth and causing the mucus retention is reported. Microscopically, the lesion was characterized by unicystic cavity exhibiting the lumen partially filled by papillary projections of the ductal epithelium with varying degree of oncocytic metaplasia. Based on the histopathological analysis, the differential diagnosis of oral intraductal papillomas and other ductal neoplasms of salivary origin are discussed.

Intraductal Papilloma Arising From the Minor Salivary Glands of the Larynx: A Case Report

It is rare for intraductal papilloma, a benign papillary tumor, to occur in the salivary glands. To our knowledge, intraductal papilloma occurring in the minor salivary glands of the larynx has not been reported. In this report, we describe a case of intraductal papilloma that occurred in the minor salivary glands of the larynx. A woman in her 30s presented with hoarseness and dyspnea since a year. Fiber-optic laryngoscopy revealed a submucosal tumor involving the left aryepiglottic fold and the left false vocal fold. Computed tomography and magnetic resonance imaging revealed a 17 × 15 × 10 mm³ mass with homogenous isodensity, with regular, well-defined margins located on the left aryepiglottic fold and the left false vocal fold. Surgical resection was performed, and subsequently a diagnosis of intraductal papilloma was made by pathologic evaluation. During the follow-up period of over 3 years, the lesion has not recurred. In conclusion, intraductal papilloma of the minor salivary glands should be considered in the differential diagnosis of laryngeal submucosal tumors.

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.

Papillary cystadenoma of the parotid gland: A case report

BACKGROUND

Papillary cystadenoma is a rare benign epithelial tumor of the salivary gland, which is characterized by papillary structures and oncocytic cells with rich eosinophilic cytoplasm. We found only one case of papillary cystadenoma in nearly 700 cases of salivary gland tumors. Our case was initially mistaken for a tumor of the right temporomandibular joint (TMJ) capsule rather than of parotid gland origin. Preoperative magnetic resonance imaging (MRI) and computed tomography (CT) should be carefully studied, which allows for appropriate preoperative counseling and operative planning.

CASE SUMMARY

Here, we report an unusual case of a 54-year-old woman with a parotid gland papillary cystadenoma (PGPC) that was misdiagnosed as a tumor of the right TMJ capsule. She was initially admitted to our hospital due to a mass anterior to her right ear inadvertently found 5 d ago. Preoperative CT and MRI revealed a well circumscribed tumor that was attached to the right TMJ capsule. The patient underwent a resection through an incision for TMJ, but evaluation of an intraoperative frozen section revealed a benign tumor of the parotid gland. Then we removed part of the parotid gland above the temporal facial trunk. The facial nerve was preserved. Postoperative histopathological findings revealed that the tumor was PGPC. No additional treatment was performed. There was no recurrence during a 20-mo follow-up period.

CONCLUSION

The integrity of the interstitial space around the condyle in MRI or CT should be carefully evaluated for parotid gland or TMJ tumors.

Intraductal papilloma arising from the accessory parotid gland: A case report and literature review

RATIONALE

Intraductal papillomas of the accessory parotid glands are extremely rare benign tumors that are most commonly derived from minor salivary glands and are easily misdiagnosed as other diseases. Studying these lesions by pathology and immunohistochemistry can raise awareness of the disease, reduce the rate of misdiagnosis, and provide more precise treatments.

PATIENT CONCERNS

A 35-year-old man first presented to our hospital with a 6-month history of a painless mass on his left parotid gland.

DIAGNOSES

The patient was diagnosed with intraductal papilloma of the accessory parotid gland by pathology and immunohistochemistry.

INTERVENTIONS

The mass was completely resected.

OUTCOMES

After 2 years of postoperative follow-up, the patient recovered well without recurrence.

LESSONS

Intraductal papilloma of the accessory parotid gland is very rare, and can easily be misdiagnosed as sialadenoma papilliferum, inverted ductal papilloma, or papillary cystadenoma, among others. It is necessary to analyze its pathology and immunohistochemistry in comparison with other diseases. Early excision and long-term follow-up are necessary to provide optimal treatment and to better understand the pathological processes of intraductal papilloma.

Sialadenoma papilliferum: A rare case report and review of literature

Sialadenoma papilliferum (SP) classified under the ductal papillomas by the WHO is a rare benign tumor of minor salivary glands. It is a rare lesion of salivary glands predominantly affecting the minor glands. It has characteristic exophytic and endophytic clinical growth pattern. Histopathologically, it is characterized by papillary projections supported by fibrovascular connective tissue core and infiltrated with mixed inflammatory cells. The ductal lining epithelium of double-layered cells of luminal layer of tall columnar cells and a basilar layer of small cuboidal cells shows additional papillary projections into the lumen. We report a case of SP of mid palate.

Sialadenoma Papilliferum: Analysis of Seven New Cases and Review of the Literature

Sialadenoma papilliferum (SP) is a rare benign salivary gland neoplasm that comprises from 0.4 to 1.2% of all salivary gland tumors. The tumor is so named because of its microscopic resemblance to the syringocystadenoma papilliferum, an uncommon benign tumor of sweat gland origin. The purpose of this paper is to report the clinical and microscopic features of seven new cases of SP and combine them with cases previously reported in the English language literature to further define this unusual lesion. Combining our cases with acceptable cases from the literature, the palate (especially the hard palate) was the most common site, with 80% of the cases occurring in this location. Other locations in decreasing order were buccal mucosa, upper lip, retromolar pad, and parotid gland. Age at diagnosis ranged from 18 to 87 years with a peak in the 6th decade and an average age of 56.4 years. Microscopically, the lesions demonstrated a papillary surface morphology, and the papillary projections varied from long and pointed to short and blunted. The supporting connective tissue contained a variable number of convoluted ductal structures, which often fused with the overlying surface epithelium. The ductal structures exhibited papillary infoldings and were lined by a double layer of epithelium consisting of basal cell layer and a luminal layer of cuboidal-to-columnar ductal cells. Immunohistochemical reactivity with p63 and p40 indicated that the basal cell layer was comprised predominantly of neoplastic myoepithelial cells. The luminal cells were immunoreactive with epithelial membrane antigen characteristic of ductal cell differentiation. Conservative surgical treatment was accomplished in most cases and appears to be adequate treatment as only two recurrences were documented. Several case reports of purported malignant transformation in SP have been reported in the literature, but in our opinion, there is insufficient evidence in the publications to unequivocally determine whether any of the malignancies truly originated within a pre-existing SP.

Update from the 4th Edition of the World Health Organization Classification of Head and Neck Tumours: Tumors of the Salivary Gland

The salivary gland section in the 4th edition of the World Health Organization classification of head and neck tumors features the description and inclusion of several entities, the most significant of which is represented by (mammary analogue) secretory carcinoma. This entity was extracted mainly from acinic cell carcinoma based on recapitulation of breast secretory carcinoma and a shared ETV6-NTRK3 gene fusion. Also new is the subsection of "Other epithelial lesions," for which key entities include sclerosing polycystic adenosis and intercalated duct hyperplasia. Many entities have been compressed into their broader categories given clinical and morphologic similarities, or transitioned to a different grouping as was the case with low-grade cribriform cystadenocarcinoma reclassified as intraductal carcinoma (with the applied qualifier of low-grade). Specific grade has been removed from the names of the salivary gland entities such as polymorphous adenocarcinoma, providing pathologists flexibility in assigning grade and allowing for recognition of a broader spectrum within an entity. Cribriform adenocarcinoma of (minor) salivary gland origin continues to be divisive in terms of whether it should be recognized as a distinct category. This chapter also features new key concepts such as high-grade transformation. The new paradigm of translocations and gene fusions being common in salivary gland tumors is featured heavily in this chapter.

Sialadenoma Papilliferum with Inverted Pattern in a Young Patient: A Case Report

Patient: Male, 20

Final Diagnosis: Sialadenoma papilliferum with inverted pattern

Symptoms: Intraoral nodular mass

Medication: —

Clinical Procedure: Surgery – excision

Specialty: Surgery

Proposed Clinico-Pathological Classification for Oral Exophytic Lesions

Oral exophytic lesions often have proven to be diagnostically challenging due to the varied clinical presentation. The exophytic growth of the oral lesions is due to the type of pathology and histological changes. Careful clinical interpretation with a better histological understanding of exophytic lesions may ease the diagnosis from the differential diagnosis panel. The purpose of proposing classification system is to categorize the exophytic lesions of interest under specific clinical and/or histological explanation; and this will eventually lead to better understanding of the pathological condition that is described. To the best of our knowledge, there is no such classification system available for oral exophytic lesions and hence proposal of classification system is attempted in this study. Further, proposing a new classification system is not just to influence the academic contribution, but also to assist at greatest extent for diagnosis during clinical practice.

Stensen's Duct Carcinoma with a Papillary Architecture

Primary carcinoma of the parotid duct (Stensen's duct carcinoma) is a rare entity, first described in 1927 and with approximately thirty-one cases reported in the English literature. Criteria for diagnosis are primarily demonstration of an origin from the Stensen's duct lining and exclusion of parotid gland, accessory parotid, oral mucosal and adjacent minor salivary gland origin. The carcinoma is usually of a specific type, and most have been described as squamous, mucoepidermoid, or undifferentiated adenocarcinomas. We report an unusual case of Stensen's duct carcinoma showing a primarily basaloid phenotype with focal squamous differentiation and a partial papillary architecture raising the possibility of malignant transformation in a ductal papilloma. Wide local excision was performed with postoperative radiotherapy and the patient is free of complications one and a half years postoperatively. Due to the small number of cases reported, the overall prognosis is not well defined, but seems to depend on the tumour size. Regional metastasis confers a 14 % mortality rate but there appears to be no relationship between histological type and prognosis.

A rare case report of mucinous cystadenoma with immunohistochemical analysis and review of literature

Cystadenomas are rare salivary gland tumours characterised by prominent epithelium-lined papillary projections into the cystic spaces. A 37 year-old female, presented with a swelling on the right side of the hard palate. Clinically, the swelling was soft, fluctuant, sessile and non-tender measuring 2.5 × 2 cm in diameter. Excisional biopsy was performed. The histopathological and immunohistochemical features were characteristic of mucinous cystadenoma. There has been no recurrence over a 2-year follow up period. The article highlights its clinical, histopathological, immunohistochemical features and differential diagnosis along with review of literature. Cystadenoma of the palate is rare, papillary variety being more common than mucinous with very few cases reported in literature.

Buccal mucosa tumour around the parotid papilla

We present a case of a 50-year-old male patient with a lump around the right parotid papilla. A 25×20 mm soft pendulous lump was identified around the right parotid duct. After obtaining non-malignant results from a tissue biopsy, we resected the tumour to preserve the right parotid duct under local anaesthesia. The patient had an uncomplicated postoperative course and maintained normal salivary secretion function. Based on the histopathological features, the lump was thought to have developed secondary to being repeatedly bitten. Several cases of parotid duct disease have been reported, but a literature search revealed that the present case is rare.

Papillary cystadenocarcinoma of the hard palate

Papillary cystadenocarcinoma (PCC) is an uncommon malignant tumour of the salivary gland, sometimes involving the minor salivary gland. Previously this entity was classified as an atypical type of adenocarcinoma, malignant papillary cystadenoma, low-grade papillary adenocarcinoma or mucus producing adenopapillary carcinoma. PCC is a glandular tumour with an indolent biological behaviour characterised by cysts and papillary endophytic projections. We report two cases of PCC involving the minor salivary gland of the hard palate. Both the patients presented with a swelling in the palate with difficulty in chewing. MRI revealed an extensively destructive lesion involving hard palate, alveolar ridge and maxillary antrum. Clinical and radiological features suggested the malignant nature of the lesion. Histopathology of incisional biopsy revealed tumour proliferation in a multicystic pattern, with extensive papillary proliferation. Diverse and cellular cytomorphology, and cellular and nuclear pleomorphism with few mitotic figures were the prominent features. Both the lesions were confirmed as PCC.

Intraductal papilloma: atypical presentation

Ductal papillomas have unique papillary features arising from the salivary gland duct system. They comprise three rare benign adenomas, namely, inverted ductal papilloma, sialadenoma papilliferum, and intraductal papilloma. Intraductal papilloma is an extremely rare benign salivary gland tumor that occurs most commonly in the minor salivary glands. Here, we are presenting a case report of intraductal papilloma in an 18-year-old patient.

CD44 expression in intraoral salivary ductal papillomas and oral papillary squamous cell carcinoma

CD44 is a transmembrane adhesion molecule which has been previously shown to be useful in the differentiation of benign papillary lesions from invasive carcinoma in several different areas including sinonasal mucosa and breast tissue. CD44 expression has previously been shown to be lost in invasive carcinoma and retained in benign papillary lesions in both of the above locations. In addition, studies have evaluated oral mucosal lesions for CD44 expression and found a loss with invasive squamous cell carcinoma when compared to normal epithelium, hyperplasia, and squamous papillomas, which stained particularly strongly. To the best of our knowledge, no study has evaluated CD44 expression when comparing salivary ductal papillomas in comparison to oral papillary SCCA. In this study 18 cases of intraductal papilloma were compared to 19 cases of oral papillary SCCA. Within the ductal papilloma group, all cases stained either absent (6%), weakly (33%), or moderately (61%) with 76% expressing the stain diffusely and 24% focally. In comparison, the papillary squamous cell carcinoma cases expressed the CD44 moderately (26%) or strongly (74%) with 100 % showing diffuse staining. Thus, the CD44 expression was contrary to expectation based on previous studies, which we hypothesize is due to the extremely well differentiated nature of papillary SCCA which expressed CD44 staining compatible with levels previously reported with oral squamous papillomas than invasive carcinoma.

Sialadenoma papilliferum: clinical misdiagnosis with a histological decree

Sialadenoma papilliferum is a rare salivary gland tumor clinically resembling papilloma originating probably from the excretory duct. It is characterized by a biphasic growth pattern of exophytic squamous component and endophytic glandular component. We report a rare case of sialadenoma papilliferum in the floor of the mouth with epithelial dysplasia with pertinent review of literature. The present case highlights the importance of keeping sialadenoma papilliferum as a differential diagnosis of exophytic papilliferous oral lesions and the need to explore the etiology and malignant potential of the tumor.

Intraductal Papilloma of the Extraglandular Segment of the Stensen Duct

Intraductal papillary neoplasm of major salivary glands is exceedingly rare. Most reported cases have been diagnosed on histopathology; an extensive literature search found no case where a preoperative imaging diagnosis was suspected or established. This report depicts the sonographic diagnosis of intraductal papilloma of the extraglandular segment of the Stensen duct. The sonographic and histological appearances of this rare entity are illustrated.

Intraductal papilloma of the parotid gland in a child

Intraductal papillomas are rare benign tumors, most commonly encountered in minor salivary glands and rarely in major salivary glands. They are cystic, solitary neoplasm that arise from ductal epithelium and produce painless swelling. We report a case of intraductal papilloma of the parotid gland in a child.

Relative frequency of intra-oral minor salivary gland tumors: a study of 380 cases from northern California and comparison to reports from other parts of the world

BACKGROUND

The relative frequency of individual intra-oral minor salivary gland tumors (IMSGT) is not well documented in the literature. The aim of this study was to determine the relative frequency and distribution of IMSGT in an oral pathology biopsy service and to compare the data with similar studies from different parts of the world.

METHODS

Files from the Pacific Oral and Maxillofacial Pathology Laboratory of the University of the Pacific, San Francisco, California served as a source of material for this study. Files were systematically searched for all cases of IMSGT during a 20-year period. Tumors were classified according to the 2005 WHO classification of salivary gland tumors.

RESULTS

IMSGT were identified in 380 (0.4%) cases of 92 860 accessed. This is the largest series of IMSGT from one source reported in recent years. Of the 380 tumors, 224 (59%) were benign and 156 (41%) were malignant. Of the benign tumors, pleomorphic adenoma (PA) was the most common (39.2%), followed by cystadenoma (6.3%), canalicular adenoma (6.1%), ductal papillomas (4.4%), basal cell adenoma (1.6%), and myoepithelioma (1.3%). Of the malignant tumors, mucoepidermoid carcinoma was the most common (21.8%), followed by polymorphous low-grade adenocarcinoma (7.1%), adenoid cystic carcinoma (6.3%), adenocarcinoma, not otherwise specified (NOS; 2.1%), acinic cell carcinoma (1.6%), clear cell carcinoma, NOS (1.0%), and carcinoma ex PA (0.5%).

CONCLUSIONS

Studies related to the relative frequency of individual IMSGTs from different parts of the world are difficult to compare because many studies are outdated, the number of cases is small, the list of tumors is limited, and new entities are not included. To determine the true relative frequency, more studies should be conducted, on a large number of cases from one source, by experienced pathologists in the field of salivary gland tumors.

A rare case of sialadenoma papilliferum with epithelial dysplasia and carcinoma in situ

Sialadenoma papilliferum is a rare benign tumor of salivary glands that predominantly affects intraoral minor salivary glands. It is characterized by a biphasic growth pattern of exophytic squamous component and endophytic glandular component. Malignant transformation of sialadenoma papilliferum has only been recently recognized. The present article reports a rare case of sialadenoma papilliferum with epithelial dysplasia and carcinoma-in-situ in the exophytic component.

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.