This document presents a case report of a rare occurrence of basal cell adenoma in the palate of a 25-year-old male patient. It describes the clinical findings and diagnostic workup including imaging, biopsy, histopathological examination, and immunohistochemical analysis of the excised tumor. The pathological features were consistent with basal cell adenoma. The tumor was successfully removed surgically and the patient recovered well, with the tumor representing an unusual site for this rare minor salivary gland tumor.

1. A rare occurrence of basal cell
adenoma of palate: A case report
Dr. Abhay Partap Singh Brar
BDS Final year
Dasmesh Institute of Research and Dental Sciences, Faridkot

2. INTRODUCTION
• Salivary gland tumors are relatively uncommon lesions affecting
predominantly major salivary glands, especially the parotids.
Tumors of minor salivary gland account for 9-23% of all salivary
gland tumors.
• It is estimated that minor salivary gland tumors represent 0.5-1.5%
of all the head and neck admissions.
• Basal cell adenoma (BCA) is one of the rare minor salivary gland
tumor classified under benign salivary gland adenomas in the
Second Edition of the Salivary Gland Tumours Classification of the
World Health Organization (WHO) and accounts for approximately
1.8% of all salivary gland epithelial tumors.
• In 1967, Kleinsasser and Klein introduced the term "basal cell
adenoma" to describe a benign salivary gland tumor comprised of
uniform-appearing basaloid cells arranged in solid, trabecular,
tubular, and membranous patterns; but lacking the myxoid and
chondroid mesenchymal-like component as seen in pleomorphic
adenoma.

3. INTRODUCTION………….
• The majority of monomorphic adenomas shows a nonaggressive
behavior and are adequately treated with soft tissue palatal
excision.
• Morphological variability, together with the relative rarity of a
number of minor salivary gland tumors, can sometimes make
diagnosis difficult, despite the abundance of named tumor entities.
• Unfortunately, the morphological variability of these tumors is
mirrored by the immunocytochemical profiles which further
complicate the diagnosis.
• Considering the rarity of this lesion and histologic paradox regarding
its diagnosis, I hereby present a case of BCA of palate with
emphasis on comprehensive Immunohistochemical analysis.

4. CASE REPORT
• A 25-year-old male patient reported with the chief complaint of painless
swelling with respect to left side of palate since 6 months.
• Swelling was insidious in onset, it started initially as a small intraoral mass
and gradually progressed to present size of 3 × 4 cm in largest extent with
history of repeated ulcerations.
• Clinical examination revealed no extraoral swelling and lymphadenopathy.
Intraoral examination revealed a soft movable submucous mass on the left
side of the palate extending anterioposteriorly from distal 25 to distal of
28 and mediolaterally from the free gingival margins to 1 cm short of
midline.
• Overlying mucosa was ulcerated but showed no secondary changes. The
swelling was soft, non-fluctuant and nontender with no evidence of
paresthesia. A provisional diagnosis of adenoma of minor salivary gland of
palate was made.

5. Figure 1: Soft tissue palatal mass extending anterioposteriorly from distal 25 to
distal of 28 and mediolaterally from the free gingival margins to 1 cm short of
midline

6. • Radiological examination including panoramic and occlusal view
revealed no abnormality.
• Computed tomography scan did not reveal any underlying bone
resorption and mass was localized without any invasion into
surrounding anatomical cavities.
• On aspiration, negative pressure was observed suggestive of solid
lesion. An incisional biopsy was performed and subjected for
histopathological examination.
• Histopathology showed encapsulated tumor mass composed of
sheets of large and small basaloid cells with nuclear staining varying
from pale to hyperchromatic. Cells were arranged in numerous
strands and cords in solid and tubular pattern which were separated
from each other by hyalinized connective tissue stroma. These
features were suggestive of BCA

7. • The tumor was subsequently excised under general anesthesia with
1 cm margins along with overlying palatal mucosa and resected
tissue specimen was submitted for histopathological examination.
• To reconfirm our diagnosis, tissue-sections were further subjected
to immunohistochemical (IHC) analysis using panel of markers. Pan-
cytokeratin (pan-CK), CK 5/6, and S100 showed positive
immunoreactivity; Calponin and p63 showed focal staining,
whereas CD 117 and smooth muscle actin (SMA) showed negative
staining [Table 1].
• These findings reconfirmed our definitive diagnosis of BCA.
• The wound was allowed to heal by secondary intention and the
patient had an uneventful recovery and is under regular follow-up
since 6 months.

8. Figure 2: Photomicrograph showing: (a) Sheets of large and small basaloid cells arranged separated by
hyalinized connective tissue stroma, (H and E stain, ×4) and inset showing high power view (×40) of basaloid
cells. (b) Intense positive immunostaining for pan-CK, (c) intense positive immunostaining for CK 56, (d)
moderately positive immunostaining for calponin, (e) moderately positive immunostaining for S100, (f) focal
immunostaining for p63, (g) focal immunostaining for Ki 67, (h) negative immunostaining for SMA, and (i)
negative immunostaining for CD117. CK=Cytokeratin, SMA=Smooth muscle actin

9. Table 1: Differential diagnosis of lesions with
basaloid proliferation

10. DISCUSSION
• BCA is a rare benign salivary gland neoplasm characterized by the
basaloid appearance of the tumor cells and absence of the
myxochondroid stromal component as seen in pleomorphic
adenoma.
• The BCA occur more frequently in the parotid gland, followed by
the minor salivary glands of the upper lip, buccal mucosa, and
rarely on lower lip and palate.
• In the present case, the palatal location of the tumor represents a
very unusual site. Extensive review of pertinent cases in PubMed
and Medline data using keywords "basal cell adenoma of palate"
and "basal cell adenoma of minor salivary glands" revealed only
four cases

11. DISCUSSION
• The tumor can occur at any age, but is most common in middle-
aged and older adults, with peak prevalence in the 7 th decade of
life. In contrast to review of literature, present case occurred in
3 rd decade of life.
• Differential diagnosis of BCA must be established with some
unfavorable entities such as basal cell adenocarcinoma, adenoid
cystic carcinoma (AdCC), and basaloid squamous cell carcinoma as
all these lesions show basaloid proliferation.
• So, there is need of IHC analysis to differentiate BCA from such
prognostically different set of tumors, but unfortunately there was
scarcity of comprehensive IHC analysis in literature published which
can often lead to erroneous diagnosis.

12. DISCUSSION
• Malignant transformation to basal cell adenocarcinoma is rare;
however, few cases have been reported.
• Although recurrence is rare, the membranous subtype, which is a
hereditary variety of BCA, has a 25-37% recurrence rate, possibly
related to its multifocal nature, which impairs complete removal.
• Management of benign tumors requires local soft tissue palatal
excision. There is no need to fenestrate the palate and removal of
bone is unnecessary.

13. CONCLUSION
• Salivary gland tumors can show a striking range of
morphological diversity between different tumor types and
sometimes within an individual tumor mass.
• In addition, hybrid tumors, dedifferentiation and the
propensity for some benign tumors to progress to
malignancy can confound histopathological interpretation.
• Definitive diagnosis by clinical and imaging techniques
alone is difficult.
• IHC plays an imperative role in diagnosis of salivary gland
tumors to support the histological assessment.
• As it is difficult to delineate the exact behavior of lesions
which are insufficiently reported in literature, a close
regular follow-up after surgical treatment is mandatory.

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