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.

Infarction of basal cell adenoma of the parotid gland: First case report and literature review on CTNNB1 I35T mutations in salivary basal cell neoplasms

Infarction has rarely been reported in some types of salivary gland tumors. In this study, we present the first case of infarction occurring in salivary basal cell adenoma. A 62-year-old male presented with swelling in the left parotid region. Histopathological examination revealed extensive central necrosis surrounded by a rim of viable tumor tissue showing the typical histology of basal cell adenoma. Nuclear β-catenin expression and the CTNNB1 p.I35T (c.104 T > C) mutation were identified in the tumor. A diagnosis of basal cell adenoma with central necrosis was made, and the postoperative period was uneventful. In addition, we review the literature on CTNNB1 I35T mutations in basal cell neoplasms of the salivary glands. Awareness of the possible occurrence of infarction and the high frequency of the unique mutation in basal cell adenoma may help in the differential diagnosis of salivary gland tumors.

Basal Cell Adenoma and Basal Cell Adenocarcinoma: a 50-year Experience From a Single Institution

BACKGROUND

Basal cell adenoma (BCA) and adenocarcinoma (BCAd) are two of the least frequent salivary gland tumors. We describe the largest series of these neoplasms, spanning over a period of 50 years (1970-2020), diagnosed and treated in a single Institution.

METHODS

Sixty-eight cases were identified. Clinical and pathological data were collected and correlated with outcome.

RESULTS

Forty-one BCA and 27 BCAd were identified. BCA cases had almost pristine prognosis, with only a relapse in a tumor inadequately excised. Ten patients with BCAd developed metastases, and 14 died from the disease. The 2-year and 5-year survival was of 76% and 42%.

CONCLUSIONS

The importance of adequate excision is reinforced in BCA, with no recurrences occurring when margins were negative. Contrary to previous reports, BCAd was not associated with a good prognosis. A better understanding of the genetics of these neoplasms may identify therapeutic options when dealing with inoperable or metastatic disease.

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.

Evaluation of MR imaging findings differentiating parotid basal cell adenomas from other parotid tumors

PURPOSE

To evaluate the usefulness of magnetic resonance imaging (MRI) to differentiate basal cell adenomas (BCAs) from other parotid tumors.

METHOD

A total of 136 patients with histologically proven parotid gland tumors (13 BCAs, 66 pleomorphic adenomas [PAs], 30 Warthin tumors [WTs], and 27 parotid cancers [PCs]) who underwent a cervical MRI study between December 2011 and March 2019 were retrospectively enrolled. The MRI findings of the tumors were evaluated by two board-certified radiologists.

RESULTS

All 13 of the BCAs showed smooth margins, while 19 of the 27 PCs showed irregular margins (p < 0.0001). Eleven BCAs had some cystic components, and five were cyst-dominant. The BCAs had significantly more cystic components than the PAs (p = 0.0077). The mean apparent diffusion coefficient (ADC) value of the BCAs was 1.21 ± 0.20 × 10^-3 mm²/sec, which was equivalent to that of the PCs (1.12 ± 0.25 × 10^-3 mm²/sec, p = 0.76), significantly lower than that of the PAs (1.61 ± 0.32 × 10^-3 mm²/sec, p < 0.0001), and significantly higher than that of the WTs (0.81 ± 0.19 × 10^-3 mm²/sec, p = 0.0004). The plateau time-intensity curve (TIC) was the most common type for both BCAs and PCs, seen in 8 of 12 BCAs and 21 of 26 PCs, with no significant difference between these groups (p = 0.34).

CONCLUSIONS

BCA should be considered a possibility when a parotid lesion has smooth margins with an entire capsule and includes a cystic component, even if the TIC and diffusion-weighted MR images suggest a malignant pattern.

Basal Cell Adenoma and Basal Cell Adenocarcinoma

Basal cell adenoma (BCA) and basal cell adenocarcinoma (BCAC) are uncommon biphasic salivary gland tumors having morphologic similarities to other biphasic salivary gland neoplasms having differentiation toward the intercalated ducts of the salivary gland. Both tumors show mixtures of trabecular, tubular, solid, and membranous solid patterns. BCAC is separated from BCA primarily by the presence of invasion in the former. The diagnosis of BCA and BCAC is best carried out with hematoxylin and eosin-stained sections and careful attention to detail of tumors in the differential diagnosis, including adenoid cystic carcinoma, pleomorphic adenoma, and epithelial myoepithelial carcinoma.

Basal cell adenocarcinoma of the parotid gland: Comparison with basal cell adenoma for preoperative diagnosis

OBJECTIVE

To summarize the diagnosis and treatment outcomes of basal cell adenocarcinoma (BCAC) of the parotid gland, a rare low-grade malignancy, at a single institution, and to investigate the treatment approach for this rare malignancy.

METHODS

We conducted a retrospective analysis of 9 patients with BCAC during 20 years from September 1999 to December 2019. Forty-five patients with basal cell adenoma (BCA), who were treated during the same time period, were used for comparison. The clinical characteristics of BCAC, diagnostic imaging, the usefulness of fine-needle aspiration cytology (FNAC) and frozen section biopsy (FSB), histological assessment of malignancy, and treatment outcomes were investigated.

RESULTS

There were no marked differences in sex, age, tumor diameter, or tumor location between BCAC and BCA cases. Among the 9 patients with BCAC, one patient was noted with pain/tenderness, and two patients were observed with adhesion to the surrounding tissues. Only one patient was diagnosed as malignant based on MRI/US. FNAC for BCAC was suspicious for malignancy in 6 of the 9 cases, which included one patient with the correct grade of malignancy, one patient with malignancy only, and 4 patients suspicious for malignancy. FSB was suspicious for malignancy in 8 of the 9 cases. Malignancy grade was determined based on infiltration to the surrounding tissues and expression of Ki-67, p53, and bcl-2. One patient with infiltration to the surrounding tissue was diagnosed as intermediate-grade malignancy, while the remaining 8 patients were diagnosed as low-grade malignancy. The BCAC cases included 7 patients with T2 and 2 patients with T1. Conservative resection was performed for all patients, and all cases are surviving cancer-free.

CONCLUSION

The malignancy of BCAC can be suspected before surgery based on symptoms/signs, diagnostic imaging, and FNAC. FSB enables the diagnosis of not only malignancy but also the grade of malignancy, which may help determine the appropriate surgical resection. Although all 9 patients with BCAC are surviving free from cancer, a long-term follow-up is warranted.

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.

Basal cell adenoma of sublingual salivary gland: A rare entity

Monomorphic adenoma or Basal cell adenoma (BCA) is a benign epithelial tumor of glandular origin. It has very unique histological characteristic and its diagnosis is mainly established by histological examination. Most common occurrence is in parotid gland and rarely reported in submandibular and sublingual salivary glands. In this case report, we are presenting a case of basal cell adenoma of sublingual gland.

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.

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.

A large basal cell adenoma extending to the ipsilateral skull base and mastoid in the right parotid gland: A case report

BACKGROUND

Basal cell adenoma (BCA) is a rare benign tumour that has unique histological characteristics and primarily arises in the parotid glands. According to published reports, nearby tissue destruction by BCA seems impossible.

CASE SUMMARY

We presented a case of a 54-year-old woman with a mass in the deep lobe of the right parotid gland involving the ipsilateral skull base and mastoid. The patient exhibited gradual right facial swelling but no other obvious symptoms. Combined resection of the total right parotid gland and partial skull base excision were performed. The biopsy conducted before the surgery and sections cut from intraoperatively obtained tissues were not definitive for identifying the character of the neoplasm. A final diagnosis of tubular BCA without malignant elements was established based on postoperative pathology results and immunohistochemical analysis. The tumour did not recur during the 12-mo follow-up period.

CONCLUSION

A diagnosis of BCA can only be established based on a histopathological examination after an excisional biopsy, and tubular BCA should carefully be considered as a destructive type.

Difference in transducin-like enhancer of split 1 protein expression between basal cell adenomas and basal cell adenocarcinomas - an immunohistochemical study

Background

Basal cell adenoma (BCA) and basal cell adenocarcinoma (BCAC) are benign and malignant, basaloid salivary gland neoplasms, respectively. These tumors show a dual-cell proliferation of inner luminal/ductal cells and outer abluminal/myoepithelial or basal cells. The only difference between them is defined as a malignant morphology such as invasion. Recently, the nuclear expression of β-catenin and a catenin beta-1 (CTNNB1) mutation were found in BCA. Transducin-like enhancer of split 1 (TLE1) belongs to the Groucho/TLE family, and it functions in the “off” state in the Wnt/β-catenin signaling pathway. We hypothesized that if the dysregulation of the Wnt/β-catenin signaling pathway could be attributed to the tumorigenesis of BCA/BCAC, there might be differences in TLE1 expression between BCA and BCAC.

Method

The study included 35 BCA and 4 BCAC cases. We performed immunohistochemistry to detect TLE1 and β-catenin and investigated the catenin beta-1 (CTNNB1) mutational profile among BCA and BCAC cases.

Results

In BCA, the expression of TLE1 was confined to luminal cells of glandular structures, in contrast to the expression of β-catenin in abluminal cells. The BCA cases harbored CTNNB1 gene mutations (12/35). In BCAC, luminal cell staining of TLE1 was identical to BCA in non-invasive areas (4/4) but indistinct in invasive areas (3/4). The BCAC cases were β-catenin positive for abluminal cells in both areas. The BCAC cases had CTNNB1 mutation (2/4) and the laser-captured microdissection allowed the separate collection of infiltrative and non-infiltrative areas to detect the same mutation.

Conclusions

Immunohistochemical analysis for TLE1 can identify BCA and BCAC by luminal cell staining difference, especially indistinct luminal cell expression for TLE1 in invasive areas of BCAC. Moreover, TLE1 can be luminal/ductal cell markers.

Potential Difficulties in Cytological Approach of Basal Cell Adenoma of Salivary Glands: The Experience of a Single Institution

OBJECTIVE

Basal cell adenoma (BCA) is an uncommon benign epithelial neoplasm of salivary glands, which was first described by Kleinsasser and Klein in 1967 and which derives its name from the monomorphic basaloid appearance of tumor cells. This tumor represents 1-2% of all salivary gland epithelial tumors; the most common site of occurrence is the parotid gland. It usually arises in adults over 50 years of age with slight female prevalence.

STUDY DESIGN

We analyzed 5 cases of parotid lesions investigated by fine needle aspiration cytology at a single institution between 2002 and 2018.

RESULTS

Our series was composed by 3 women and 2 men with a mean age of 62 years. The most important cytological criteria we observed were cohesive sharp-angled clusters of regular basaloid cells, palisaded by p63-positive myoepi-thelial cells, and bordered by basement membrane-like hyaline membrane in the absence of a myxochondroid stroma. Overall features were consistent with the diagnosis of BCA.

CONCLUSIONS

Our aim is to highlight the cytological features of these rare lesions improving the awareness of cytological pitfalls of salivary gland basaloid neoplasms. Moreover, the goal of this paper is to add to the literature 5 additional cases of these unusual tumors.

Wnt/β-catenin signal alteration and its diagnostic utility in basal cell adenoma and histologically similar tumors of the salivary gland

Differential diagnosis among basal cell adenoma (BCA), basal cell adenocarcinoma (BCAC), adenoid cystic carcinoma (ACC) and pleomorphic adenoma (PA) of the salivary gland can be challenging due to their similar histological appearance. Although frequent nuclear β-catenin expression and CTNNB1 mutations have been reported in BCA, further details of the Wnt/β-catenin signal alterations are unclear. The aim of this study was to assess the diagnostic utility of Wnt/β-catenin signal alteration in BCA and morphological mimics. We performed immunohistochemical staining for β-catenin and mutation analysis for Wnt/β-catenin-related genes (CTNNB1, APC, AXIN1 and AXIN2) in BCA (n = 34), BCAC (n = 3), ACC (n = 67) and PA (n = 31). We also analyzed ACC-specific MYB and MYBL1 gene rearrangements by fluorescence in situ hybridization (FISH). Nuclear β-catenin expression (≥3%) was present in 32/34 cases (94.1%) of BCA, and the nuclear β-catenin labeling index was significantly higher than in other tumor types (p = < 0.0001). In BCA, we found mutations in CTNNB1, APC and AXIN1 genes (41.1%, 2.9% and 8.8%, respectively). In BCAC, nuclear β-catenin expression with CTNNB1 mutation was present in 1/3 cases (33.3%). As for ACC, nuclear β-catenin expression was observed in 3/67 cases (4.4%), but all 3 cases harbored either MYB or MYBL1 gene rearrangement. The results suggest that nuclear β-catenin immunoreactivity with appropriate criteria may be helpful to distinguish BCA from histologically similar tumors. However, a minor subset of ACCs with nuclear β-catenin expression require careful diagnosis. In addition, Wnt/β-catenin signal alteration may play a role in the pathogenesis of BCA and BCAC.

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.

Next-Generation Sequencing in Salivary Gland Basal Cell Adenocarcinoma and Basal Cell Adenoma

Basal cell adenoma and basal cell adenocarcinoma represent basaloid salivary gland neoplasms that show cyto-morphologic similarity but differ at the histologic level by their invasive qualities, as adenocarcinomas show invasion beyond their capsule, a finding not seen in the adenomas. Due to the low incidence of these tumors, the molecular mechanism underlying their pathogenesis is poorly understood. We sought to further delineate these neoplasms through mutation profiling by targeted next-generation sequencing (NGS). Twenty cases (basal cell adenocarcinoma = 10; basal cell adenoma = 10) were retrospectively selected from a previous analysis. NGS was performed using the Ion AmpliSeq™ Cancer Hotspot Panel v2 (Life Technologies, Carlsbad, CA). The data was analyzed using the Ion Torrent Suite Software (Life Technologies) followed by a laboratory-developed pipeline. One of eight cases of basal cell adenocarcinoma had a mutation, which was an activating mutation in PIK3CA (c.3140A>G, p.H1047R). No mutations were detected in the remaining basal cell adenocarcinomas. In the basal cell adenomas, the CTNNB1 p.I35T mutation was identified in three of nine (3/9) cases. A missense mutation in the ATM gene (c.2572T>C, p.F858L) was seen in a basal cell adenoma with an allele frequency of 53 %, raising the possibility of a germline mutation. The overall findings suggest that although there is cytomorphologic similarity, differences exist between these two tumors at the histologic and genetic level. Although the numbers of cases are limited, the aberrations in genes affecting different signaling pathways in the basal cell adenocarcinoma versus the basal cell adenomas suggest that basal cell adenocarcinoma likely arises de novo and not from basal cell adenoma.

Basal Cell Adenoma of Parotid Gland: Case Report and Review of Literature

Basal cell adenoma (BCA) of the salivary gland is a rare neoplasm consists of a monomorphic population of basaloid epithelial cells, and it accounts for approximately 1-2 % of all salivary gland tumors. Its most frequent location is the parotid gland. It usually appears as a firm and mobile slow-growing mass. Histologically, isomorphic cells in nests and interlaced trabecules with a prominent basal membrane are observed. In contrast to pleomorphic adenoma, it tends to be multiple and its recurrence rate after surgical excision is high. Due to prognostic implications, differential diagnosis with basal cell adenocarcinoma, adenoid cystic carcinoma and basaloid squamous cell carcinoma is mandatory. We report a case of BCA of the parotid gland. We also review the literature and discuss the diagnosis and management of this rare entity.

Basal cell adenoma in the deep portion of the parotid gland: a case report

Basal cell adenoma (BCA) is a rare, benign neoplasm that most frequently arises in the parotid gland. We treated a 54-year-old female patient with BCA that had developed in the deep portion of the left parotid gland. The patient presented with gradual facial swelling with no other symptoms. We performed a total parotidectomy to excise the mass, but we preserved the facial nerve. Histopathology revealed a well-encapsulated mass. The tumor was composed of islands of comparatively uniform, small, dark, basaloid epithelial cells in the stroma. Histologic and immunohistochemical studies concluded that the BCA tumors were mostly trabecular. Postoperatively, there was no facial nerve weakness, and the tumor did not recur during the 24-month follow-up period.

Synchronous Ipsilateral Parotid Tumors with Cytologic-Histologic Correlation

Synchronous ipsilateral tumor formation within a major salivary gland is a very rare event. In this case, a 54-year-old female tobacco smoker presented with a slowly enlarging left parotid gland. Computed tomography of the neck demonstrated a solid mass superficial to a cystic mass in the deep lobe of the gland. Ultrasound-guided fine needle aspiration yielded oncocytic cells, lymphoid cells, and granular debris along with rare cohesive groups of basaloid cells. Parotidectomy was performed, and the resected gland was found to contain two adjacent but distinct masses. One mass, a predominantly solid, well-circumscribed lesion composed of ribbons of double-layered oncocytic cells and a lymphoid stroma with germinal center formation, was a Warthin tumor. The other mass, a predominantly cystic lesion composed of cords and nests of basaloid cells with associated deposits of basement membrane-like material, was a basal cell adenoma of the membranous type. To our knowledge, this is the first reported case of synchronous Warthin tumor and basal cell adenoma of the parotid gland with cytologic-histologic correlation attributable to each tumor.

Epithelial-Mesenchymal Transition Protein Expression in Basal Cell Adenomas and Basal Cell Adenocarcinomas

Basal cell adenomas and basal cell adenocarcinomas show marked histomorphologic similarity and are separated microscopically primarily by the invasive characteristics of the adenocarcinomas. We wished to explore potential differences in the expression of epithelial-mesenchymal transition associated proteins in these two tumor types. A tissue microarray was constructed utilizing 29 basal cell adenomas and 16 basal cell adenocarcinomas. Immunohistochemical expression of E-cadherin, beta-catenin, Twist 1 and vimentin were investigated. Both tumors expressed all proteins in a relatively similar manner. Nuclear beta-catenin was essentially limited to the abluminal cell populations in both tumor types. E-cadherin was limited largely to luminal locations but was more prevalent in the adenocarcinomas as compared to the adenomas. Primarily abluminal expression for vimentin was seen, sometimes present in an apical dot-like pattern. Distinct populations of cellular expression of these four markers of epithelial mesenchymal transition were present but were similar in locations in both tumors with no patterns discerned to separate basal cell adenoma from basal cell adenocarcinoma. Given these findings, the mechanisms by which basal cell adenocarcinoma is able to invade while its counterpart, basal cell adenoma can not, may be more complex than in other tumor types.

Basal Cell Adenoma of the Parotid Gland-A Rare Entity

Salivary gland tumors are uncommon and constitute about 2.0 to 6.5 % of all head and neck tumors. Incidence of basal cell adenoma is about 1 to 3 % of salivary gland tumors. We present a rare case of basal cell adenoma of the parotid and a review of literature.

Basal Cell Adenoma of Palate, a Rare Occurrence with Review of Literature

Basal cell adenoma is an uncommon benign epithelial neoplasm of salivary gland which derives its name from the basaloid appearance of tumor cells and accounting for 1-2 % of all salivary gland epithelial tumors. This tumor usually arises in the major salivary glands, with the parotid being the most frequent site of occurrence, followed by the upper lip; while it is very rare in the minor salivary glands. Microscopically, it is composed of isomorphic cells similar to basal cells with nuclear palisading. We report a case of BCA presenting as an asymptomatic swelling over the right side of palate of 55-year-old female patient. A follow-up of 1 year revealed no recurrence. This report emphasizes the rare site of occurrence of this tumor and briefly reviews the literature.

Basal cell adenoma-clinicopathological, immunohistochemical analysis and surgical considerations of a rare salivary gland tumor with review of literature

Introduction:

Basal cell adenoma (BCA) of the salivary glands is a rare benign salivary gland tumour. Differentiation of BCA from varied entities involving maxillofacial area is mandatory.

Aim:

To analyze the clinicopathological, histopathologic features, immunohistochemcal analysis and surgical considerations of this rare entity.

Materials and Methods:

This study included 12 cases of BCA from archives of department reported over the period of 13 years. All the pertaining clinicopathologic features such as incidence, age, sex and site of lesions were assessed. Tissue sections were stained by using panel of immunohistochemical markers, i.e. Pan CK, CK 5/6 and S100, Calponin, p63, CD 117 and smooth muscle actin.

Results:

BCA was observed in 26-52 years age group (mean age, 38.75 years) with female propensity of 7:5 male to female ratio. It is seen more commonly in parotid gland, followed by upper lip, buccal mucosa and palate. Solid type is the most common histopathologic type followed by tubular, membranous and trabecular. Only one case of membranous type of BCA showed recurrence. Pan CK, CK 5/6 showed strong immunoreactivity, calponin showed moderate staining, p63 and Ki-67 mild staining, whereas CD 117 and SMA showed negative immunostaining.

Conclusion:

Vigilant comprehensive analysis of all the pertaining clinicopathologic and histopathologic features and immunohistochemical analysis are required for differentiating from other lesions with basaloid differentiation having varying prognosis.

Basal cell adenoma of the parotid gland: clinical and pathological findings in 29 cases

OBJECTIVE

To determine the clinical and pathological features of basal cell adenoma (BCA) of the parotid gland.

METHODS

This is a retrospective study of 29 parotid BCAs in 28 patients who underwent surgery at the Department of Otolaryngology Head and Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, between October 2000 and June 2013. The tumors were categorized according to their location in the parotid gland as superior superficial lobe, inferior superficial lobe and deep lobe.

RESULTS

The mean age was 57.0 years (range, 32-83 years). The clinical manifestations of parotid BCAs were consistent with those of other benign parotid tumors. There were no significant differences in age, average disease duration and tumor size among the three tumor groups. There were 11 deep tumors (11/29, 37.9%), and five of them exhibited cystic degeneration (5/11, 45.5%). A total of 15 patients underwent FNAB examination, and the results were positive in seven patients (7/15, 46.7%). Mild facial nerve function impairment occurred in five patients (House-Brackmann grade II), of whom, three had recovered by the 6-month follow-up. No cases of local recurrence or malignant transformation were observed during follow-up.

CONCLUSION

The clinical features of BCA are consistent with those of other benign tumors. The deep lobe of the parotid gland is more likely to develop BCAs, and thus, this diagnosis should be considered in patients with deep-lobe tumors, especially when accompanied with cystic degeneration. FNAB can increase the rate of preoperative diagnoses.

Basal cell adenoma of nasal septum: report of a case and review of literature

Basal cell adenoma is an uncommon benign salivary gland neoplasm, presenting isomorphic basaloid cells with a prominent basal cell layer. Basal cell adenoma arising from the nasal septum is exceptionally rare. Reports on positron emission tomography with 2-deoxy-2-fluorine-18-fluoro-D-glucose (18FDG-PET) imaging for basal cell adenoma are limited. Here, we present the case of a 49-year-old man who had the symptoms of intermittent repeated bleeding from the left nose for half a year. 18FDG-PET scanning showed increased accumulation of 18FDG with its characteristic benign pathology has a potential to malignancy. After removal of the mass, the patient became symptom free. Pathology showed basal cell adenoma. The evidence of active and growing cells was present in the specimen.

Basal cell adenoma of the parotid gland: Cytological diagnosis of an uncommon tumor

Basal cell adenoma (BCA) is a rare benign epithelial tumor of the salivary gland, displaying monomorphic basaloid cells without a myxochondroid component, representing 1-3% of all salivary gland neoplasms seen predominantly in women over 50 years of age. It is uncommon in young adults. Cytodiagnosis of basaloid tumors chiefly basal cell adenoma of the salivary gland, is extremely challenging. The cytological differential diagnoses range from benign to malignant, neoplastic to non- neoplastic lesions. Histopathological examination is a must for definitive diagnosis, as these entities differ in prognosis and therapeutic aspects. We present a 22-years-old male with this uncommon diagnosis with a discussion on the role of cytological diagnosis. Fine needle aspiration cytology is a simple, minimally invasive method for the preoperative diagnosis of various types of neoplastic and non-neoplastic lesions. The knowledge of its pitfalls and limitations contributes to a more effective approach to treatment.

Basal Cell Adenoma of Submandibular Salivary Gland: A Case Report and Literature Review

BACKGROUND

Salivary gland tumours constitute about 3-4 % of all head and neck neoplasms. Approximately 80 % originate in the parotid gland and they are rarely present in the submandibular gland. Basal cell adenoma is a benign epithelial salivary gland tumour that appears to have unique histologic characteristics. The diagnosis of this entity must be established by histological study.

CASE REPORT

The literature revealed only four reported cases of basal cell adenoma of submandibular salivary gland. This article presents a rarely occurring basal cell adenoma as a fifth reported case in submandibular salivary gland in a 23 year old female.

DISCUSSION

A rare case of basal cell adenoma of submandibular salivary gland is reported with clinical features, diagnosis, histopathological features and treatment modalities. When there is involvement of submandibular gland with a tumour the histopathological confirmation is mandatory instead of relying on FNAC and it must be differentiated from pleomorphic adenoma, adenoid cystic carcinoma, adenocarcinoma due to its prognostic implications.

CONCLUSION

Entities like basal cell adenoma can only be established by histopathological examination after excisional biopsy. The treatment done also affects the ultimate prognosis. As such the surgeon has to make his clinical decision based on many factors like history, clinical examination, histopathological examinations, radiological examination and immunohistochemistry study. No single criteria should be relied upon. We recommend to carry out genetic pattern study in a person with basal cell adenoma to rule out pathogenesis and establish a correct diagnosis of it for better understanding and prognosis.

Basal cell adenoma in the parotid: a bizarre myoepithelial-derived stroma rich variant

Basal cell adenoma (BCA) is a specific entity that lacks the myxochondroid stromal component of a pleomorphic adenoma. There are six histopathological types of BCA: solid, tubular, trabecular, membranous, cribriform, and myoepithelial-derived stroma rich. Myoepithelial-derived stroma rich variant is so rare, especially with cellular atypia. Herin we describe a rare case of BCA arising in the parotid on a 25-year-old man. A well-demarcated nodule arising in the parotid that was composed of basaloid cells, forming small duct-like or tubular structures containing basement membrane-like material, as well as highly cellular elongated cells with hyperchromatic, enlarged, pleomorphic, and bizarre nuclei. Immunohistochemically, S100 protein and p63 highlighted the basal aspect of the peripheral epithelial cells and peripheral spindle and bizarre cells, while CK7 expressed on the luminal cells. We made a diagnosis of "basal cell adenoma, myoepithelial-derived stroma rich variant, with bizarre myoepithelial proliferation". The differential diagnosis includes cellular pleomorphic adenoma, basal cell adenocarcinoma, and carcinoma ex pleomorphic adenoma. After follow-up for 3 years, there was no evidence of recurrence. Further pathological characteristics of this disease are discussed.

Membranous basal cell adenoma arising in the eyelid

Basal cell adenoma (BCA) is a specific entity that lacks the myxochondroid stromal component of pleomorphic adenoma. Membranous basal cell adenoma is a rare variant of BCA, which is characteristic by abundant eosinophilicextracellular hyaline material deposited either inside or at the periphery of the epithelial islands. Herin we describe the first case of membranous BCA arising in the upper eyelid in a 38-year-old woman. A well-demarcated nodule arising in the eyelid was composed of isomorphic basaloid cells organized with a prominent basal cell layer and distinct basement membrane-like material. Immunohistochemically, S100 protein and p63 highlighted the basal aspect of the peripheral epithelial cells, while CK7 expressed on the luminal cells. A diagnosis of membranous basal cell adenoma of the eyelid was made. At follow-up for 2 years and 3 months later, there was no evidence of recurrence. Further pathological characteristics of this disease are discussed.

Basal cell adenoma in a relatively rare site

Basal cell adenoma (BCA) of the salivary glands is an uncommon type of monomorphic adenoma. Its most frequent location is the parotid gland. It usually appears as a firm and mobile slow-growing mass. Histologically, it is seen as nests of isomorphic cells and interlaced trabeculae with a prominent basal membrane. There is also slack, hyaline stroma with absence of a myxoid or chondroid component. We describe a case of BCA of palatal minor salivary glands, a rare site for its occurrence. We also briefly review the literature on the same.

Basal cell adenoma of the upper lip from minor salivary gland origin

Basal cell adenoma is an uncommon benign salivary gland neoplasm, presenting isomorphic basaloid cells with a prominent basal cell layer. Taking into account that basal cell adenomas represent 1% of all salivary gland tumors, being the majority of cases in the parotid glands, the goal of this paper is to report a case of basal cell adenoma of the upper lip arising from minor salivary gland.

A rare case of bilateral basal cell adenomas in the parotid glands

We report a very rare case of bilateral parotid tumors in a 55-year-old female patient who presented with left parotid mass of 7 × 7 cm size since 8 years and right parotid mass of 2.5 × 1.5 cm size since 2 years duration. Based on clinical features a provisional diagnosis of bilateral pleomorphic adenomas was made. Results of fine needle aspiration cytology of both masses were inconclusive. Bilateral superficial conservative parotidectomy with facial nerve preservation revealed bilateral encapsulated and lobulated tumors which on histopathological examination revealed bilateral basal cell adenomas in both parotid glands.