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.Keywords: Basal cell adenoma, basal cell adenocarcinoma, monomorphic adenom

Choudaha, N

Gandi, L

Ghosh, AK

Majumdar, S

Pal, SP

Sharma, I

Singh, AD

Nigerian Journal of Surgery

English

PubMed

AJOL - African Journals Online

31Nigerian Journal of Surgery Jan‑Jun 2015 | Volume 21 | Issue 1IntroductIonBasal cell adenoma (BCA) of  the salivary glands is a rare benign tumor with a high recurrence rate and, in general, good prognosis is recognized as an independent entity in the Second Edition of  the Salivary Gland Tumors Classification of  the World Health Organization (WHO).[1] The most frequent location is the parotid gland, followed by upper lip, buccal mucosa, lower lip and palate. These tumors frequently affect patients between their fifth and seventh decades. Histologically, four characteristic patterns have been described: Solid, trabecular, tubular and membranous.[2‑4] Due to prognostic implications, differential diagnosis with basal cell adenocarcinoma, basaloid squamous cell carcinoma (BSCC) and adenoid cystic carcinoma (AdCC) is mandatory. Considering the rarity of  this lesion, histologic paradox regarding its diagnosis and lack of  descriptive studies in literature directed us to analyze the clinicopathological factors, immunohistochemcal analysis and surgical considerations of  this rare entity.MAterIALs And MethodsThis study included 12 cases of  BCA from patients referred to the Department of  Oral Pathology between 2002 and 2012. All the pertaining clinic‑demographic characteristics such as incidence, age, sex and site of  lesions were collected for descriptive assessment. Three micrometer tissue sections were taken for histopathologic and immunohistochemical (IHC) evaluation. After confirmation of  the Basal Cell Adenoma‑Clinicopathological, Immunohistochemical Analysis and Surgical Considerations of a Rare Salivary Gland Tumor with Review of LiteratureAD Bhagat Singh, Swapan Majumdar1, Amal Kanti Ghosh2, Lakshmi Gandi3, Nidhi Choudaha4, Ipsita Sharma4, SP Pal5Departments of Oral Surgery, 1Prosthodontics, 2Conservative Dentistry and 5Orthodontics, Mithala Minority Dental College and Hospital, Mansukh Nagar, Darbhanga, Bihar, 3Department of Oral and Maxillofacial Surgery, Vyas Dental College and Hospital, Jodhpur, Rajasthan, 4Department of Oral Pathology, RKDF Dental College and Research Center, Bhopal, Madhya Pradesh, IndiaORiginAl ARticleAbstrActIntroduction: 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.Keywords:  Basal cell adenoma, basal cell adenocarcinoma, monomorphic adenomaAddress for correspondence: Dr. AD Bhagat Singh, Department of Oral Surgery, Mithala Minority Dental College and Hospital, Mansukh Nagar, Darbhanga, Bihar, India. E-mail: adbhagatsingh@yahoo.inAccess this article onlineQuick Response Code:Website: www.nigerianjsurg.comDOI:  *****Singh, et al.: Basal cell adenoma of salivary gland32Nigerian Journal of SurgeryJan‑Jun 2015 | Volume 21 | Issue 1previous diagnosis by two independent pathologists, tissue sections were subjected to IHC analysis by using Pan CK, CK 5/6 and S100, calponin, p63, CD 117 and SMA markers. Immunoreactivity was independently assessed by all study participants and graded into negative staining (<10%), weak, (10%‑25%), mild (26%‑50%), moderate (51%‑75%) and strong staining (76%‑100%).resuLtsA total of  12 cases of  BCA of  maxillofacial region over the period of  13 years were selected for assessment and results obtained were correlated with the findings of  differential lesions found in literature. BCA was observed in 26 ‑ 52 years age group (mean age, 38.75 years) with female propensity. It was observed more commonly in parotid gland (8) followed by upper lip (2), buccal mucosa (1) and palate (1). Solid type is most common histopathologic type followed by tubular, membranous and trabecular. [Table 1] None of  the cases showed facial nerve involvement and treatment was local excision. Follow‑up from two to six years revealed only a single case of  recurrence of  membranous type of  BCA. The lesions typically are slow growing, firm, non‑tender, asymptomatic masses with minimal chances of  recurrence [Table 1]. Pan CK and CK 5/6 showed strong immunoreactivity [Figure 1d and 1e], calponin showed moderate staining [Figure 1f], p63 and Ki‑67 mild staining [Figure 2d and 2c], whereas CD 117 [Figure 2e] and SMA showed negative immunostaining [Figure 2a and Table 2].dIscussIonPresent study focused on differentiation of  BCA from other lesions of  varied prognosis. PA is the most common benign tumor involving parotid glands and palate as the most common intraoral site (42.8 ‑ 68.8%), followed by the upper lip (10.1%) and cheek (5.5%). It is seen commonly in females of  4 ‑ 6th decade.[5] Sometimes, it is even difficult to differentiate PA and BCA histologically. In PA, palate is the most common intra‑oral site but in contrary to BCA palate is the rarest site of  occurrence. PA shows strong immunoreactivity for calponin and moderate for Pan CK and SMA indicating myoepithelial cell proliferation. It shows weak staining for Ki‑67, which is a proliferative marker and mild staining in BCA [Table 2].Differential diagnosis must be established with some unfavorable entities, such as the basal cell adenocarcinoma, AdCC and BSCC. In contrast to BCA, an infiltrative growth, more mitotic figures (>4 mitotic count/10 HPF) and Ki67‑staining of  5% of  the cells are observed in basal cell carcinoma.[6]Sometimes pathologists face a diagnostic challenge in differentiating AdCC and BCA because both the entities show proliferation of  basaloid cells. According to literature, AdCC is seen commonly in mean age of  52 years and have high Table 1: Clinicopathologic characteristics of 12 cases of basal cell adenomaIHC markersBasal cell adenomaPleomorphic adenomaBasal cell adenocarcinomaAdenoid cystic carcinomaBasaloid squamous cell carcinomaPAN CK Strong Moderate Strong Strong ModerateCK 5/6 Strong Mild Mild Moderate ModerateCalponin Moderate Strong Mild Moderate NegativeCD 117 Negative Negative Negative Strong Negativep 63 Mild Mild Strong Strong (peripheral) Mild (diffuse)Ki-67 Mild Weak Strong Strong StrongSMA Weak Moderate Negative Moderate NegativeS-100 Variable Mild Mild Strong NegativePCNA Mild Mild Strong Strong StrongPAN CK: Pan cytokeratin, SMA: Smooth muscle actin, PCNA: Proliferating cellular nuclear antigen, IHC: ImmunohistochemistryTable 2: Immunohistochemical analysis of lesions with basaloid proliferationAge (years) Gender Site Histopathologic type Treatment Follow up36 Female Parotid gland Solid Local excision No recurrence32 Female Parotid gland Solid Local excision No recurrence26 Female Parotid gland Membranous Total parotidectomy Recurrence after 9 months52 Male Palate Solid Local excision No recurrence30 Male Parotid gland Tubular Local excision No recurrence45 Female Parotid gland Solid Local excision No recurrence28 Female Upper lip Membranous Total parotidectomy No recurrence38 Male Parotid gland Solid Superficial parotidectomy No recurrence46 Female Parotid gland trabecular Local excision No recurrence52 Male Buccal mucosa Solid Superficial parotidectomy No recurrence42 Female Upper lip Tubular Local excision No recurrence38 Male Parotid gland Solid Local excision No recurrenceSingh, et al.: Basal cell adenoma of salivary gland33Nigerian Journal of Surgery Jan‑Jun 2015 | Volume 21 | Issue 1propensity for parotid glands. In AdCC there are high chances of  perineural invasion,[7] whereas the present study showed that none of  the cases of  BCA demonstrated perineural invasion. In the AdCC whirlpool of  epithelial cells, dark external cells in a stockade pattern and a thick basal membrane‑like structure are observed. Moreover, vascularization in the microcystic areas is absent, in contrast to BCA, in which multiple endothelial canals are present.[8] IHC analysis showed that CD117(c‑Kit) is a specific marker for AdCC[9] and the present study showed that it is negative for BCA. Ki‑67 and p63 markers are indicative of  proliferative activity of  tumor tissue. P63 is a selective IHC marker of  basal/stem cells of  stratified epithelium and of  myoepithelial cells.[9] Current study showed that they are strongly expressed in AdCC and weak‑mild expression in BCA. So these markers can be reliable in differentiating BCA and AdCC.BSCC is an aggressive variant of  squamous cell carcinoma (SCC), which predominantly occurs in men between the age of  60 and 70. Differentiation of  it from other entities is mandatory as it carries a very poor prognosis. It is characterized by the presence of  solid cells in a lobular fashion, which are small and have scarce cytoplasm with hyperchromatic nuclei without nucleoli. In this latter entity, both populations of  basal cells are not observed, in contrast to BCA. Continuity of  tumoral cells with epithelium of  the surface and squamous dysplasia are also observed, in contrast to BCA.[10,11] Tumoral nests are clearly differenced from inter‑epithelial stroma because of  an intact basal cell membrane. This delimitation is observed neither in the pleomorphic adenoma nor in the AdCC. Present study showed that Pan CK and CK 5/6 are strongly expressed in BCA and Ki‑67 and p63 show high immunoreactivity in BSCC.Figure 1: (a) Clinical photograph showing swelling at parotid gland region; Photomicrograph showing: (b) Cells arranged in solid and tubular pattern  in hyalinized stroma (H and E, ×10); (c) Basaloid cells in hyalinized stroma (H and E, ×10); (d) Strong Pan CK immunostaining; (e) Strong CK 5/6 immunostaining; (f) Moderate calponin immunostainingdcbfaeFigure 2: Photomicrograph showing: (a) Weak smooth muscle actin immunostaining; (b) Moderate S100 immunostaining; (c) Mild Ki-67 immunostaining; (d) Mild p63 immunostaining; (e) Negative CD117 immunostaining; (f) Mild PCNA immunostainingdcbfaeSingh, et al.: Basal cell adenoma of salivary gland34Nigerian Journal of SurgeryJan‑Jun 2015 | Volume 21 | Issue 1Other benign lesions such as the mucocele, sebaceous cyst, lipoma and nasolabial cyst are also considered in the differential diagnosis. Clinical appearance of  BCA may simulate a mucocele of  the oral mucosa. Generally, the mucocele usually appears in the lower lip of  young people, whereas BCA appears in the upper lip of  the elderly.[12]Basal cell adenocarcinoma is a malignant counterpart of  BCA. Ki‑67 and p63 are expressed intensely in case of  basal cell adenocarcinoma, basaloid squamous cell carcinoma and AdCC but in our study only focal/Mild staining was observed in BCA. [Table 2] Additionally BCA was positive for S100 and Pan CK indicating its relation to myoepithelial cells. However some authors suggest the existence of  these markers in neoplastic cells of  BCA independent of  their lineage.[13]BCA can be unencapsulated, therefore, the best treatment is adequate local excision rather than enucleation.[14] They are amenable to conservative resection such as superficial parotidectomy. Extracapsular excision is performed in cases in which there is effect on minor salivary glands in the oral mucosa. It is mandatory not to disrupt the capsule, in order to minimize the risk of  recurrence, which is observed in rare occasions.[10] The recurrence rate for the solid and trabecular‑tubular variants is almost nonexistent. The membranous type is most commonly associated with recurrence (25% to 37%), and this may be a result of  the multicentricity of  this lesion rather than because of  true recurrences, although rare, malignant transformation is more common in the membranous type than in the other types. So, total parotidectomy rather than superficial parotidectomy has been proposed in the membranous type of  BCA. Multicentric development, unencapsulation in 50% of  cases, association with eccrine tumors and malignant transformation have led some investigators to classify separately.[10,15]concLusIonVigilant comprehensive analysis of  all the pertaining clinicopathologic, histopathologic features and IHC analysis are required for differentiating lesions with basaloid differentiation which can sometimes pose challenge to pathologist. With increased awareness and acceptance of  this lesion as a separate entity by pathologists, we perhaps can expect an increase in its diagnosis.references1. Seifert G, Sobin LH. The World Health Organization´s Histological Classification of Salivary Gland Tumors. A commentary on the second edition. Cancer 1992;70:379-85.2. Mintz GA, Abrams AM, Melrose RJ. Monomorphic adenomas of the major and minor salivary glands. Report of twenty-one cases and review of the literature. Oral Surg Oral Med Oral Pathol 1982;53:375-86.3. Fantasia JE, Neville BW. Basal cell adenomas of the minor salivary glands. A clinicopathologic study of seventeen new cases and review of the literature. Oral Surg Oral Med Oral Pathol 1980;50:433-40.4. Kusama K, Iwanari S, Aisaki K, Wada M, Ohtani J, Itoi K, et al. Intraoral minor salivary gland tumors: A retrospective study of 129 cases. J Nihon Univ Sch Dent 1997;39:128-32.5. Mendenhall WM, Mendenhall CM, Werning JW, Malyapa RS, Mendenhall NP. Salivary gland pleomorphic adenoma. Am J Clin Oncol 2008;31:95-9.6. Nagao T, Sugano I, Ishida Y, Hasegawa M, Matsuzaki O, Konno A, et al. Basal cell adenocarcinoma of the salivary glands: Comparison with basal cell adenoma through assessment of cell proliferation, apoptosis, and expression of p53 and bcl-2. Cancer 1998;82:439-47.7. Sur RK, Donde B, Levin V, Pacella J, Kotzen J, Cooper K, et al. Adenoid cystic carcinoma of the salivary glands: A review of 10 years. Laryngoscope 1997;107:1276-80.8. de Vicente Rodríguez JC, López Arranz JS, Junquera Gutierrez LM, Álvarez Álvarez I, García-Pola Vallejo MJ. Adenoid cystic carcinoma and basal cell adenoma of the parotid gland: A compromised differential diagnosis. Rev Eur Odontoestomatol 1991;3:333-6.9. Nagao T, Sato E, Inoue R, Oshiro H, H Takahashi R, Nagai T, et al. Immunohistochemical analysis of salivary gland tumors: Application for surgical pathology practice. Acta Histochem Cytochem 2012;45:269-82.10. Yu GY, Ubmüller J, Donath K. Membranous basal cell adenoma of the salivary gland: A clinicopathologic study of 12 cases. Acta Otolaryngol 1998;118:588-93.11. Banks ER, Frierson HF Jr, Mills SE, George E, Zarbo RJ, Swanson PE. Basaloid squamous cell carcinoma of the head and neck. A clinicopathologic and immunohistochemical study of 40 cases. Am J Surg Pathol 1992;16:939-46.12. Zabaleta M, Mollá FJ, Salazar F, Erdozain E, Sánchez L. Monomorphic adenoma of basal cells in a minor salivary gland. Acta Otorrinolaringol Esp 1997;48:169-72.13. Gupta N, Jadhav K, Ahmed MB, Amberkar VS. Basalcell adenoma in a relatively rare site. J Oral Maxillofac Pathol 2009;13:101-4.14. Thawley SE, Ward SP, Ogura JH. Basal cell adenoma of the salivary glands. Laryngoscope 1974;84:1756-66.15. Junquera L, Gallego L, de Vicente JC, Fresno MF. Bilateral parotid basal cell adenoma: An unusual case report and review of the literature. J Oral Maxillofac Surg 2010;68:179-82.How to cite this article: ????Source of Support: Nil, Conflicts of Interest: None declared.

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

A D Bhagat Singh

Swapan Majumdar

Amal Kanti Ghosh

Lakshmi Gandi

Nidhi Choudaha

Ipsita Sharma

S P Pal

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

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Basal Cell Adenoma‑Clinicopathological, Immunohistochemical Analysis and Surgical Considerations of a Rare Salivary Gland Tumor with Review of Literature

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