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

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 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.

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.

Fine Needle Aspiration Cytology of Basal Cell Adenoma of Parotid Simulating Adenoid Cystic Carcinoma

Basal cell adenoma is a rare type of monomorphic salivary adenoma most commonly involving the parotid gland. Cytology of basal cell adenoma closely mimics many other benign and malignant basaloid neoplasms. Cytological features of membranous basal cell adenoma simulate adenoid cystic carcinoma in fine needle aspiration cytology (FNAC) smears. Here, we are presenting a rare case of cytodiagnosis of membranous basal cell adenoma of parotid gland in an elderly lady, which mimicked adenoid cystic carcinoma on FNAC. We discuss the cytomorphology of this rare case with an emphasis on cytological difference between membranous basal cell carcinoma and adenoid cystic carcinoma as well as other basaloid neoplasms.

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.