Basal cell adenoma and basal cell adenocarcinoma of the parotid gland: clinical findings and surgical outcomes in a single-institution study.

BACKGROUND: Basal cell adenoma (BCA) is a rare benign tumor within the salivary glands. Basal cell adenocarcinoma (BCAC), the malignant counterpart of BCA, is also an exceedingly rare tumor with very limited clinical studies conducted. This study aims to investigate the clinical characteristics, demographics, and surgical outcomes of patients diagnosed with BCA and BCAC within the parotid gland. METHODS: A retrospective analysis from May 2003 to August 2023 was performed for all patients undergoing parotidectomy for masses. Retrospective data on gender, age, tumor characteristics, and outcomes were collected. Surgical approaches, including negative margin attainment, capsule removal, and histological diagnosis, were also detailed. RESULTS: The study included 1268 patients who underwent parotidectomy, resulting in 81 cases of BCA and 7 cases of BCAC. BCA patients, with a mean age of 55.1 years, showed diverse age distribution and predominantly presented in the 50s. In BCAC cases, seven female patients exhibited a predominant location in the deep lobes. FNA revealed BCAC in three out of seven cases, and subsequent parotidectomy was performed, resulting in no observed recurrences or metastases. CONCLUSION: This study reports the largest number of BCA cases from a single institution and provides comprehensive insights into the demographics, tumor characteristics, and clinical outcomes of both BCA and BCAC. Although further research should be conducted, based on clinical follow-up results, appropriately including the capsule in the tumor excision indicates favorable outcomes, especially when the tumor size is not large.

Identification and characterization of primary cilia-positive salivary gland tumours exhibiting basaloid/myoepithelial differentiation.

Primary cilia (PC) are non-motile, antenna-like structures on the cell surface. Many types of neoplasms exhibit PC loss, whereas in some neoplasms PC are retained and involved in tumourigenesis. To elucidate the PC status and characteristics of major salivary gland tumours (SGTs), we examined 100 major SGTs encompassing eight histopathological types by immunohistochemical analysis. PC were present in all (100%) of the pleomorphic adenomas (PAs), basal cell adenomas (BCAs), adenoid cystic carcinomas (AdCCs), and basal cell adenocarcinomas (BCAcs) examined, but absent in all (0%) of the Warthin tumours, salivary duct carcinomas, mucoepidermoid carcinomas, and acinic cell carcinomas examined. PC were also detected by electron-microscopic analysis using the NanoSuit method. It is worthy of note that the former category and latter category of tumours contained and did not contain a basaloid/myoepithelial differentiation component, respectively. The four types of PC-positive SGTs showed longer PC than normal and exhibited a characteristic distribution pattern of the PC in the ductal and basaloid/neoplastic myoepithelial components. Two PC-positive carcinomas (AdCC and BCAc) still possessed PC in their recurrent/metastatic sites. Interestingly, activation of the Hedgehog signalling pathway, shown by predominantly nuclear GLI1 expression, was significantly more frequently observed in PC-positive SGTs. Finally, we identified tau tubulin kinase 2 (TTBK2) as being possibly involved in the production of PC in SGTs. Taken together, our findings indicate that SGTs that exhibit basaloid/myoepithelial differentiation (PA, BCA, AdCC, and BCAc) are ciliated, and their PC exhibit tumour-specific characteristics, are involved in activation of the Hedgehog pathway, and are associated with TTBK2 upregulation, providing a significant and important link between SGT tumourigenesis and PC. © 2021 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Synchronous bilateral multifocal basal cell adenomas of the parotid gland-a case report.

BACKGROUND: Bilateral parotid gland tumors account for up to 3% of cases. In this group, the vast majority are Warthin's tumors. However, bilateral presentations of other parotid gland tumor entities is also possible, an example of which is a basal cell adenoma (BCA). Bilateral BCA is extremely rare, which could cause misdiagnosing it as a Warthin tumor. CASE PRESENTATION: The current study reports the unique case of a 48-year-old woman who presented with a 6-month history of slowly growing masses located bilaterally in the parotid region, surgically treated with 5-year follow-up (no recurrence, normal facial nerve function). Magnetic resonance imaging (MRI) revealed three lesions: two in the superficial and deep lobes of the right parotid gland, and one in the superficial lobe of the left parotid gland. A total parotidectomy with facial nerve preservation was performed on the right side, and superficial parotidectomy on the left side 6 months later. Histopathological examination confirmed that all three tumors were BCAs. Molecular analysis didn't show any strong, potential of unknown clinical significance in the studied sample. CONCLUSIONS: Multifocal bilateral lesions of the parotid gland are usually Warthin tumors. Detailed preoperative diagnostics including MRI and histopathological examination is essential to avoid misdiagnosing BCA and Warthin tumors. To our best knowledge, no case of synchronous bilateral multifocal basal cell adenomas of the parotid gland has been reported in English literature so far.

A retrospective study of 30 basal cell adenomas of the salivary gland in a Brazilian population and literature review.

PURPOSE: The present study aimed to provide the clinicopathological data of Brazilian patients with basal cell adenoma (BCA). METHODS: Records of BCA cases were retrospectively gathered from the Brazilian National Cancer Institute database between 1996 and 2006. All cases were histopathologically reviewed, and the clinicopathological data were collected from the patients' medical files. In addition, an English literature review about this tumor is also presented. RESULTS: Of 1127 salivary gland tumors identified, 30 were BCAs (2.7%). Women were more affected than men (70.0% vs. 30.0%), and the majority (60.0%) were elderly (> 65 years old). The parotid gland was the most frequent location affected (93.3%), followed by the upper lip (3.3%) and submandibular gland (3.3%). Fine-needle aspiration was the main procedure applied to establish a preoperative diagnosis of tumor; however, the results were not always consistent. Histopathologically, the trabecular pattern was the most common type seen (50.0%) among our BCA samples. Most patients underwent superficial or partial parotidectomy. Frey's syndrome was reported only in one case during the follow-up. No recurrence was noted in the present series. The literature review revealed a total of 213 reported cases of BCA in the period investigated. CONCLUSIONS: This is the first case series of BCA reported in Brazil. As occurred in other previously reported series, the clinicopathological data of BCAs are similar and confirm that this type of tumor is rare, develops predominantly in the parotid gland, frequently affects older women, has an indolent behavior, and the affected patients have an excellent prognosis.

The diagnostic value of Superb Microvascular Imaging in identifying benign tumors of parotid gland.

BACKGROUND: We compared the ultrasound features, superb microvascular imaging (SMI) and micro vessel density (MVD) of pleomorphic adenoma (PA), Warthin's tumor (WT) and basal cell adenoma (BCA) to explore the clinic value of SMI in differential diagnosis of benign tumors of parotid gland. METHODS: The vascular distributions and grade by color doppler flow imaging (CDFI) and SMI, as well as vascular index (VI) of 249 parotid gland masses from 217 patients were analyzed. RESULTS: The internal echogenicity of BCA are more homogeneous in comparing with WT and PA(P < 0.05). By SMI, the vascular distribution and vascular grade in PA were mainly peripheral (33.1%) and avascular (25.7%), Grade 1 (27.8%) and Grade 0 (25.7%). WT were mainly central (31.3%) and mixed distribution (34.9%), in Grade 3 (37.3%) and Grade 2 (36.2%). BCA was mainly peripheral (33.3%) and mixed distribution (33.3%), in Grade 2 (33.3%) and Grade 3 (33.3%). The overall detection rate of SMI for vascular Grade 2 and 3 was significantly higher than that of CDFI (P < 0.05). Both VI and MVD were lowest in PA, highest in WT (P < 0.001). The VI by SMI was correlated with MVD (P < 0.001). The correlation index between vascular distribution and grade by SMI and MVD were significantly higher than CDFI. CONCLUSION: SMI can provide low-velocity blood flow information, which is helpful for the differential diagnosis of common benign tumors of parotid gland, and is expected to be more widely used.

Lipomatous basal cell adenoma (Basal cell lipoadenoma) - Report of the first two cases.

We present, to the best of our knowledge, the first two cases (60 year old female and 71 year old male) of basal cell adenoma with significant adipocytic components and suggest the term "lipomatous basal cell adenoma" for these lesions. Both tumors presented as slow growing nodules in the parotid gland. The two cases represent different points on a histopathological spectrum with one case being extremely well differentiated with distinct spiradenoma-like histological features; distinct bilayering, duct formation with secretory material and very low proliferative activity and the other case displaying more primitive cytological features composed of a predominant uniform, (p63-positive; CK 7-negative) basaloid, abluminal cell type, high proliferative activity and only scattered true ducts composed of (CK7-positive, p63-negative) luminal cells.

CTNNB1 mutations in basal cell adenoma of the salivary gland.

BACKGROUND/PURPOSE: Basal cell adenoma (BCA) and basal cell adenocarcinoma (BCAC) are uncommon salivary gland tumors comprising proliferation of basaloid cells. Nuclear ß-catenin expression and mutations in its encoding gene (CTNNB1) are reported to be specific to BCA. PIK3CA mutations are only found in BCAC not in BCA. However, in previous studies the number of cases was relatively small. The present study analyzed 44 cases of basal cell neoplasms to identify the CTNNB1 and PIK3CA mutation profiles in this rare salivary gland tumor. METHODS: The basic clinical features and detailed histological patterns of 41 BCA and three BCAC cases were analyzed. All basal cell neoplasms and a tissue microarray of adenoid cystic carcinoma (AdCC) were tested for ß-catenin immunohistochemistry. CTNNB1, PIK3CA, and CYLD mutations were detected by PCR and Sanger sequencing in each case. RESULTS: Nuclear ß-catenin expression was present in 97.6% of BCA and 66.7% of BCAC cases but not in AdCC cases. CTNNB1 mutations were found in 60% of BCA but not in BCAC. None of the tested cases had PIK3CA mutations. CTNNB1 mutation trended to be more common in those cases having a predominant tubular or tubulotrabecular patterns (p = 0.059). CONCLUSION: ß-catenin immunohistochemistry is very useful for the differential diagnosis between BCA/BCAC and AdCC. CTNNB1 mutations are common in BCA, especially those with tubular or tubulotrabecular patterns.

Immunohistochemical expression of MYB in salivary gland basal cell adenocarcinoma and basal cell adenoma.

BACKGROUND: Basal cell predominant salivary gland neoplasms can be difficult to separate histologically. One of the most aggressive of basaloid salivary gland neoplasms is adenoid cystic carcinoma. MYB expression by immunohistochemistry has been documented in adenoid cystic carcinoma. Some investigators have suggested that using this expression can help in establishing the diagnosis of adenoid cystic carcinoma. Utilizing tissue microarrays, we studied a group of basal cell adenocarcinomas and basal cell adenomas to determine: (i) whether either tumor expressed MYB and (ii) the frequency of any expression in either tumors. METHODS: Seventeen salivary gland basal cell adenocarcinomas and 30 salivary gland basal cell adenomas were used to construct microarrays. These tissue microarrays were used to assess for immunohistochemical MYB expression. RESULTS: Fifty-three percent (nine of 17) of salivary gland basal cell adenocarcinomas and 57% (17 of 30) of salivary gland basal cell adenomas showed MYB overexpression. For comparison, we studied 11 adenoid cystic carcinomas for MYB expression and found that 64% (seven of 11) overexpressed MYB. We found no relation to clinical course for basal adenomas or basal cell adenocarcinomas that overexpressed MYB vs those that did not. CONCLUSIONS: MYB expression does not help separate basal cell adenocarcinomas from basal cell adenomas, and our data suggest it does not differentiate between either of these neoplasms and adenoid cystic carcinoma.

Carcinoma ex basal cell adenoma of the parotid gland: A report of an extremely rare case.

Malignant non-basaloid tumors that arise from basal cell adenoma (BCA) are extremely rare. The patient was a 72-year-old Japanese male, who had noticed swelling of the left parotid region 21 years ago. A superficial lobectomy was performed. About 60% of the tumor was made up of cribriform and trabecular tissue composed of basaloid cells, which exhibited mild atypia and nuclear expression of ß-catenin. This portion of the tumor was considered to be a BCA. In the other part of the tumor, the proliferation of large eosinophilic atypical cells, most of which formed intraductal structures, was observed. These tumor cells displayed cellular atypia, and some of them formed Roman bridge structures or contributed to intracapsular invasion. Immunohistochemically, these cells were positive for cytokeratin 7, gross cystic disease fluid proten-15 (GCDFP-15), androgen receptor (AR), and mammaglobin (MMG) and exhibited a high Ki-67 labeling index. So, this portion of the tumor was considered to be a salivary duct carcinoma (SDC). The tumor's final diagnosis was SDC ex BCA (intracapsular type), which is extremely rare. GCDFP-15, AR, MMG, and Ki-67 are useful immunohistochemical markers for diagnosing SDC ex BCA.

Orbital basal cell adenoma: A case report.

Basal cell adenomas are uncommon benign epithelial tumors of the salivary gland. Orbital basal cell adenoma of the orbit has not been described before. The authors report an unusual case of basal cell adenoma that presented in the orbit. Immunohistochemical findings for the tumor are also described.

Differences in MYB expression and gene abnormalities further confirm that salivary cribriform basal cell tumors and adenoid cystic carcinoma are two distinct tumor entities.

BACKGROUND: In practices, some cases of salivary basal cell tumors that consist mainly of cribriform growth pattern are difficult to differentiate from adenoid cystic carcinoma (AdCC). Identification of reliable molecular biomarkers for the differential diagnosis between them is required. METHODS: Twenty-two cases of cribriform salivary basal cell tumors (at least 10% cribriform pattern present in each tumor) comprising 18 cases of basal cell adenoma (BCA) and four cases of basal cell adenocarcinoma (BcAC) were collected between 1985 and 2008. Twenty cases of cribriform AdCC were retrieved from our archives. MYB protein expression and gene abnormalities were detected in all cases by immunohistochemistry (IHC) and fluorescent in situ hybridization (FISH) analyses, respectively. RESULTS: Neither MYB protein nor split genes were detected in any of the cases of cribriform basal cell tumors, while 55% (11/20) of cases of cribriform AdCC had MYB protein expression. High MYB expression was detected in 81.8% (9/11) cases, while low expression was found in the remaining cases. FISH analysis indicated that nine AdCC tumors with high MYB protein expression were split gene-positive, while MYB gene splitting was not detected in the 11 cases with low or absent MYB protein expression. CONCLUSION: The molecular changes in AdCC differ from those associated with cribriform basal cell tumors, which further confirms that cribriform basal cell tumors and AdCC are two distinct tumor entities. Simultaneous detection of MYB protein expression and the associated molecular changes could be beneficial in differentiating salivary cribriform basal cell tumors from AdCC.

Tubular variant of basal cell adenoma shares immunophenotypical features with normal intercalated ducts and is closely related to intercalated duct lesions of salivary gland.

AIMS: The morphological criteria for identification of intercalated duct lesions (IDLs) of salivary glands have been defined recently. It has been hypothesised that IDL could be a precursor of basal cell adenoma (BCA). BCAs show a variety of histological patterns, and the tubular variant is the one that presents the strongest resemblance with IDLs. The aim of this study was to analyse the morphological and immunohistochemical profiles of IDLs and BCAs classified into tubular and non-tubular subtypes, to determine whether or not IDL and tubular BCA represent distinct entities. METHODS AND RESULTS: Eight IDLs, nine tubular BCAs and 19 non-tubular BCAs were studied. All tubular BCAs contained IDL-like areas, which represented 20-70% of the tumour. In non-tubular BCA, IDL-like areas were occasional and small (<5%). One patient presented IDLs, tubular BCAs and IDL/tubular BCA combined lesions. Luminal ductal cells of IDLs and tubular BCAs exhibited positivity for CK7, lysozyme, S100 and DOG1. In the non-tubular BCA group, few luminal cells exhibited such an immunoprofile; they were mainly CK14-positive. Basal/myoepithelial cells of IDLs, tubular BCAs and non-tubular BCAs were positive for CK14, calponin, α-SMA and p63; they were more numerous in BCA lesions. CONCLUSIONS: IDL, tubular BCA and non-tubular BCA form a continuum of lesions in which IDLs are related closely to tubular BCA. In both, the immunoprofile of luminal and myoepithelial cells recapitulates the normal intercalated duct. The difference between the adenoma-like subset of IDLs and tubular BCA rests mainly on the larger numbers of myoepithelial cells in the latter. Our findings indicate that at least some BCAs can arise via IDLs.

Basal cell adenoma of salivary glands with a focal cribriform pattern: clinicopathologic and immunohistochemical study of 19 cases of a potential pitfall for diagnosis.

Cribriform type of salivary basal cell adenoma (cBCA) is relatively rare and problematic in distinction from adenoid cystic carcinoma (AdCC). The aim of this study was to investigate the clinicopathology and immunoprofile of cBCA. Nineteen cases of cBCA with at least a 30% area of cribriform structure under microscope were analyzed by the description of their histopathologic and immunohistochemical features using the antibodies of matrix metalloproteinase-9 (MMP9), CK8&18, calponin, SMA, S100, P63, CD117, and laminin. The patients of cBCA ranged from 24 to 71 years with a distinct predilection for females (79%). The tumor was well-circumscribed and had no recurrent tendency after a local excision followed by a median of 67 months. Enhanced computed tomography (CT) showed that the tumor was rich in blood supply. Microscopically, it was mainly composed by the basaloid cells with the peripheral palisading. The cells around the cribriform pattern expressed P63 protein and had almost no immunoreactivity for calponin, SMA, S100, or CK8&18. The expression level of MMP9, laminin, and CD117 were significantly lower in cBCA than those in AdCC. Good circumscription, lack of infiltrative properties, and absence of MMP9, laminin, CD117, and myoepithelial marker (SMA, S100 and calponin) in the cells around the cribriform spaces, are the most reliable points for differential diagnosis of cBCA from AdCC.

Surgical management of basal cell adenoma of the parotid gland: A case report and review of the literature.

INTRODUCTION AND IMPORTANCE: Basal cell adenoma (BCA) is a rare, benign tumor of the salivary gland. It has distinct histologic features that are different from mixed tumors of the salivary gland. Often times, it occurs in the parotid gland. Usually it appears as a hard, slowly growing, asymptomatic lump that may exist for years prior to treatment. Pathologically, BCA tumors demonstrate a monomorphic basaloid cell population devoid of myxochondroid components. This rather uncommon tumor's clinical appearance, pathological characteristics, differential diagnosis, and available treatments have been briefly described. CASE PRESENTATION: A 52-year-old female patient presented with a longstanding, gradual facial asymmetry that resulted from a mass of parotid region. She had no other symptoms. Radiology and cytology test results were suggestive of a benign salivary gland tumor of the parotid gland. A superficial parotidectomy was successfully done with a preservation of the facial nerve. Histopathology reported concluded the diagnosis of BCA trabecular subtype. During the 12-month follow-up period, the tumor did not recur, and there was no postoperative impairment of the facial nerve. CLINICAL DISCUSSION: Imaging studies, including CT scans and MRI, are helpful in determining the tumor's size, location, and relationship to adjacent structures. The definitive diagnosis is achieved through histopathology. This clinically asymptomatic mass requires early recognition, a prompt therapeutic intervention and long-term follow-up. CONCLUSION: As clinicians, it is critical that we have a thorough understanding of clinicopathology in terms of clinical presentation, pathology, diagnosis, treatment, and prognosis of this rare tumor.

A presentation of basal cell adenoma: a case report.

BACKGROUND: While statistically rare in comparison to other head and neck tumours, parotid gland swellings are often encountered in clinical practice where one of the primary goals of examination becomes distinction between benign and malignant lesions. Hallmarks of malignancy are characterized by a female preponderance, history of radiation exposure, a positive family history, and clinical features like heterogenous consistency, fixity to skin/underlying tissues and involvement of facial nerve. CASE PRESENTATION: Here we present a case of parotid swelling in a 72-year old gentleman from south India that had a curious amalgamation of both benign and malignant features. CONCLUSIONS: While benign, the risk of malignant transformation and rare multicentric occurrence indicates a need to keep basal cell adenoma in mind in case of parotid swellings and their surgical management.

Basal cell adenoma of the deep lobe of the parotid gland misdiagnosed as mucoepidermoid carcinoma - A case report.

INTRODUCTION: Basal cell adenoma is a rare, benign epithelial tumour of the salivary gland, comprising only 1-2 % of all salivary gland tumours. Predominantly found in the parotid gland, basal cell adenoma can also occur in minor salivary glands and are often confused with other benign and malignant salivary gland tumours. A thorough histopathological examination can provide a definitive diagnosis. PRESENTATION OF CASE: A 65-year-old woman presented with a painless mass in the right infra-auricular region. Imaging revealed a well-defined hypodense lesion in the deep lobe of the right parotid gland, initially suspected as mucoepidermoid carcinoma. Fine needle aspiration was inconclusive, leading to the decision to perform a total conservative parotidectomy. Histopathology confirmed basal cell adenoma, characterized by cystic areas filled with mucoid material and basaloid cells arranged in trabecular and tubular patterns. DISCUSSION: Basal cell adenoma was classified as a distinct entity by the WHO in 1991. Cytologically, they imitate both benign and malignant salivary as well as non-salivary gland tumours. The histological hallmark of basal cell adenoma involves basaloid cells with small round nuclei showing no atypia, scant pale cytoplasm, and distinct peripheral palisading. Treatment involves surgical removal, with a more radical approach for certain variants such as the membranous type. CONCLUSION: This case highlights the clinical, radiological, and histopathological features of basal cell adenoma, emphasizing the importance of accurate diagnosis and appropriate surgical management. Early detection and appropriate treatment are crucial for optimizing patient outcomes in basal cell adenoma management.

Basal Cell Adenoma of the Upper Lip: Report of a Rare Case With Literature Review.

Basal cell adenoma (BCA) is a rare, benign tumor originating from the epithelial cells of the salivary glands. It was earlier categorized as a subtype of monomorphic adenoma with distinctive histopathological features. BCA usually manifests as asymptomatic, slow-growing masses that exhibit a site and age predilection, commonly affecting the major salivary glands of elderly female patients. Histologically, solid, trabecular, tubular, and membranous patterns are recognized. It is imperative to establish a precise distinction between BCA, pleomorphic adenoma, and malignant salivary gland tumors before initiating treatment to ensure effective management. The standard treatment approach is surgical resection of the tumor. Recurrence and malignant transformation rarely occur, except for the membranous subtype. This article aims to report an unusual case of BCA arising from a minor salivary gland in the upper lip. The post-operative course was unremarkable, with complete healing of the surgical site. No recurrence was observed during a one-year follow-up. BCA arising from a minor salivary gland in the upper lip is an extremely uncommon entity. A comprehensive review of BCA in the upper lip, reported from 1991 to December 2023, revealed only 14 cases.

Association of Membranous Basal Cell Adenoma and Basal Cell Adenocarcinoma With Brooke-Spiegler Syndrome.

Basal cell adenoma (BCA) and basal cell adenocarcinoma (BCAC) are uncommon basaloid biphasic salivary gland tumors composed of basal and ductal cells. BCAC is differentiated from BCA by the presence of invasion in BCAC. In this paper, an 82-year-old woman presented with a palpable 3 cm immobile mass in her right parotid gland. A computed tomography (CT) scan showed two separate right parotid masses. She underwent a right parotidectomy, and the pathology showed multiple membranous BCAs and BCAC, which were highly suspicious for Brooke-Spiegler syndrome (BSS). This paper discusses BCA, BCAC, and their relationship with BSS.

Diagnostic role of DOG-1, GFAP and B-catenin in Basal cell Adenoma and Cellular Pleomorphic Adenoma of the Salivary Gland.

BACKGROUND: Pleomorphic Adenoma (PA) and Basal cell adenoma (BCA) are benign salivary gland tumors that may pose a diagnostic challenge if typical features are not present. Due to the increased relapse and malignant transformation rate of the former, a correct diagnosis carries relevant prognostic information. Even though immunohistochemistry (IHC) plays a limited role in the diagnosis of these tumors, the use of IHC panels could increase diagnostic accuracy. In the present work, we aimed to demonstrate that the use of an IHC panel consisting of Glial Fibrillary Acid Protein (GFAP), B-Catenin and Discovered On GIST 1 (DOG-1) can aid in the differential diagnosis between PA and BCA. METHODS: We analyzed 18 cases of benign salivary gland tumors (Pleomorphic adenomas and Basal cell adenomas) with overlapping histologic features. First, a head and neck pathologist diagnosed the cases relying on morphology alone. Afterwards, cases were re-evaluated considering the IHC panel results. Inter-observer IHC scoring concordance was evaluated with pre-defined marker cut-off points using Cohen's Kappa scores. RESULTS: Based on morphology alone, 9 cases were classified as PA while the remaining tumors were considered to be BCA. Five out of nine BCA cases showed GFAP staining and absent nuclear B-catenin and DOG-1 positivity. Conversely, 2 PA cases showed absent GFAP and positive nuclear B-catenin with concurrent DOG-1 expression. Therefore, after IHC evaluation, up to 40% of morphologic diagnoses were reconsidered. Overall, the inter-observer concordance for IHC evaluation was good (resulting Kappa Scores between 0.78 and 1). CONCLUSION: Our work supports the use of a concise IHC panel to improve the diagnostic accuracy of benign salivary gland tumors with overlapping histologic features.

Basal cell adenoma of the floor of the mouth masquerading as ranula- A rare case in an unusual location.

A 65-year-old female patient with a history of wearing a denture for 15 years reported with a complaint of pain in the floor of the mouth. On examination, a swelling measuring about 2.2 X1.2 cms was noted in the floor of the mouth on the left side. The lesion was excised under local anesthesia. Histopathology revealed a cystic lesion with basaloid cells arranged in tubules, nests and cribriform pattern. A diagnosis of basal cell adenoma was made and confirmed by immunohistochemistry. We report a rare case of Basal Cell Adenoma of the floor of the mouth which mimicked a ranula. The predominantly cystic nature of this basaloid tumor posed a diagnostic challenge. Histopathological and immunohistochemical analysis to arrive at a definitive diagnosis aid in treatment planning and prognostication.