Carcinoma ex pleomorphic adenoma of the buccal region is composed of salivary duct carcinoma and squamous cell carcinoma components

Salivary duct carcinoma with squamous differentiation: histomorphological and immunophenotypical analysis of six cases

BACKGROUND AND AIMS

Salivary duct carcinoma (SDC) is an aggressive salivary malignancy with multiple morphological subtypes. Primary salivary squamous cell carcinoma (SCC) requires exclusion of high-grade salivary malignancies and metastatic disease and is considered exceptionally rare. We report six cases of SDC with resemblance to SCC on account of variable, but often extensive, squamous differentiation.

METHODS AND RESULTS

A retrospective review (2009-2023) at two institutions of SDC with histological and immunophenotypical evidence of squamous differentiation identified six cases. Medical charts and available glass slides were reviewed. There were five males and one female with a median age of 63 years, with tumours involving the parotid (five of six) and submandibular (one of six) glands. All six tumours showed a conventional SDC component comprising < 5-90% of viable tumour. Squamous differentiation comprised 10-95%+ (> 75% in three of six cases) of total viable tumour, and demonstrated CK5/6, p63 and/or p40 immunoexpression in all cases. A sarcomatoid component, comprising 10-60% of viable tumour, was present in three of six (50%) cases. All tumours were androgen receptor (AR)-positive, but only two of six (33.3%) retained AR immunoreactivity in the squamous component. Metastatic SDC to regional lymph nodes exhibited exclusive squamous differentiation in two of six (33.3%) cases.

CONCLUSION

Squamous differentiation, histologically and immunophenotypically, can be extensive in SDC. AR expression may be lost in the squamous component and metastases may demonstrate only squamous differentiation. These findings cast further doubt on the existence of primary salivary SCC. SDC should be considered whenever encountering a carcinoma with squamous differentiation in major salivary glands or within cervical lymph nodes in the setting of a salivary mass.

Squamous Cell Carcinoma Ex Pleomorphic Adenoma of the Parotid Gland: Unusual Entity and Diagnostic Pitfalls

BACKGROUND

Carcinoma ex pleomorphic adenoma (PA) of the salivary gland with squamous cell carcinoma (SCC) component is extremely rare and can be easily misdiagnosed as a benign PA or SCC (primary or metastatic).

CASE REPORT

A 75-year-old male who had no significant past medical history, presented with a rapid growing right parotid gland mass. A fine needle aspiration revealed malignant cells. Following partial parotidectomy, a 2.4 cm ill-defined mass was grossly identified. Microscopically, it showed a keratinizing SCC with adjacent component of residual PA. Immunohistochemically, the malignant tumor cells were positive for p40, p63 and CK5. The residual PA was focally positive for CAM5.2, SMA, p63 and S100. The pathological features were consistent with SCC ex PA. The patient was well at the 7 month-follow-up post-surgery.

CONCLUSION

SCC ex PA is a rare entity that can be mistaken for a benign PA with squamous metaplasia, or primary or metastatic SCC. It behaves aggressively and has high recurrence and metastasis rate. Awareness of this disease and the diagnostic pitfalls are essential to avoid misinterpretation in difficult cases.

Parotid Salivary Duct Carcinoma With a Prominent Squamous Component: Immunohistochemical Profile, Diagnostic Pitfalls, and Therapeutic Implications

Salivary duct carcinoma of the parotid gland is a highly aggressive epithelial malignancy morphologically resembling high-grade, invasive, and in situ breast carcinoma. It can occasionally present with variable morphology making it diagnostically challenging in cases with unusual morphological components. Ancillary testing, particularly androgen receptor (AR) positivity on immunohistochemistry, can be very helpful in cases that demonstrate extensive squamous morphology, since AR positivity is uncommon in both the primary salivary gland and metastatic squamous cell carcinomas to the parotid. In this report, we describe a case of salivary duct carcinoma that showed only a squamous cell carcinoma component on the initial primary tumor site biopsy, as well as in subsequent contralateral neck lymph node and skin metastases. Apart from the variable morphology, the typical salivary duct and squamous cell carcinoma tumor components also showed significant immunohistochemical differences, including differential staining of human epidermal growth factor receptor 2/neu. The associated diagnostic pitfalls, distinct immunoprofiles of the tumor components, helpful adjuncts for making the correct diagnosis, and associated therapeutic implications are discussed.

Acantholytic Squamous Cell Carcinoma and Salivary Duct Carcinoma Ex-pleomorphic Adenoma of the Submandibular Gland: A Report of Two Extremely Rare Cases with an Immunohistochemical Analysis

Carcinoma ex pleomorphic adenoma (CXPA) is a malignant tumor of the salivary gland that arises from pleomorphic adenoma (PA). Squamous cell carcinoma (SCC) is extremely rare in the salivary glands. We report two cases of acantholytic SCC (ASCC) ex PA. Case 1 involved a 72-year-old female, and case 2 involved a 67-year-old male. Histologically, both cases involved PA, and salivary duct carcinoma (SDC) components, which were positive for androgen receptor (AR) and gross cystic disease fluid protein (GCDFP)-15 but negative for HER2, were seen in the intracapsular regions. The invasive components consisted of ASCC, which were positive for cytokeratin 5/6 and p63 but negative for AR and GCDFP-15. The SDC and ASCC components were positive for the epidermal growth factor receptor. In both cases, the cytoplasmic localization or decreased expression of E-cadherin was observed in the ASCC. In the early phase, CXPA might emerge as SDC, and it might change into SCC as it invades beyond the capsule due to changes in microenvironment. Also, the aberrant expression of E-cadherin is related to acantholysis in SCC.

Buccal space tumours

OBJECTIVE

To review the available literature as it pertains to the buccal space with a specific focus on the pathologies encountered within this space. Clinical presentation, investigations, and surgical approaches to the region are also reviewed.

METHODS

A systematic review of the available literature was performed on buccal space tumours from 1980 to 2017. Data was extracted on clinical presentation, investigations and surgical approaches to the buccal space. The pathologies encountered in the buccal space were reviewed and presented.

RESULTS

Forty-nine unique articles were reviewed, with a total 217 patients. The age of the patients ranged from 0 to 83 with a mean age of 45.8. A total of 51 pathologies were reported. The majority of these were vascular and salivary gland pathologies. The majority of salivary gland neoplasms were malignant. However a wide variety of benign and malignant soft tissue tumours were also reported to occur in this region.

CONCLUSIONS

The buccal space is a small and complex region with a variety of pathologies occurring within it. This review clarifies the differential diagnosis of a mass which presents in this area and the pathologies which occur within it.

Pedunculated carcinoma ex pleomorphic adenoma of the nasal cavity: A unique case report

BACKGROUND

A carcinoma ex pleomorphic adenoma (CXPA) is an epithelial malignancy arising in or from a benign pleomorphic salivary adenoma. The parotid gland is the most common location of CXPAs. Minor salivary gland CXPAs of the nasal cavity are exceedingly rare, with only 6 documented in the literature.

METHODS AND RESULT

We present a 7th case: an unusual pedunculated intranasal CXPA, which had a favorable outcome after a wide endoscopic excision and the longest follow-up period reported to date. The clinical features, immunohistochemical characteristics, treatment choices, and disease outcomes of the intranasal CXPAs reported in previous studies are also reviewed.

CONCLUSION

This case demonstrates the importance of considering the possibility of CXPA in the differential diagnosis of minor salivary gland malignancies in the nasal cavity.

Carcinoma Ex Pleomorphic Adenoma: Is It a High-Grade Malignancy?

PURPOSE

The objective of this study was to investigate the clinicopathologic features of carcinoma ex pleomorphic adenoma (CXPA) and comprehensively improve an understanding of this disease.

MATERIALS AND METHODS

This retrospective study investigated 151 cases of histologically confirmed CXPA. Disease-specific survival, local recurrence, and regional and distant metastases were analyzed.

RESULTS

Most cases were classed as frankly invasive CXPA (135 of 151). More than half these cases (73 of 135; 54.1%) developed local recurrence; 25 (18.5%) developed cervical metastasis; 21 (15.6%) developed distant metastasis; and 60 patients (55.6%) died during follow-up. In contrast, only 1 patient in the noninvasive CXPA group (n = 10) died after treatment for lung metastasis and 1 patient developed cervical metastasis. Similarly, only 1 patient in the minimally invasive CXPA group (n = 6) died of lung metastasis and the remaining 5 patients had an uneventful recovery after treatment.

CONCLUSIONS

Frankly invasive CXPA was a high-grade malignancy with an unfavorable prognosis. Elective neck dissection should be performed in cases of frankly invasive CXPA that originate in the submandibular gland. Patients with minimally invasive and noninvasive CXPA should be followed closely after primary treatment because regional or distant metastasis can occur.

Carcinoma ex-pleomorphic adenoma of the parotid gland consisting of high-grade salivary duct carcinoma and keratinizing squamous cell carcinoma

Carcinoma ex-pleomorphic adenoma (CXPA) is a rare salivary gland malignancy that presents diagnostic difficulties partly because of its wide range of histologic presentations. We report a case of a 77-year-old man, who presented with a 6-year history of a parotid mass that had undergone rapid growth within weeks. Magnetic resonance imaging revealed an infiltrative mass in the parotid gland, and the fine-needle aspiration (FNA) biopsy result was highly suspicious for carcinoma. Subsequent excision of the tumor demonstrated a poorly differentiated epithelial neoplasm consisting of keratinizing squamous cell carcinoma (SCC) and adenocarcinoma with regions of both ductal carcinoma in situ and invasive salivary duct carcinoma (SDC). Only focal areas exhibited a benign pleomorphic adenoma component. To our knowledge, this is the first case of a CXPA that consists of both a high-grade SDC and a keratinizing SCC in the parotid gland.

Carcinoma ex pleomorphic adenoma of the palate composed of invasive micropapillary salivary duct carcinoma and adenoid cystic carcinoma components: an unusual case with immunohistochemical approach

Carcinoma ex pleomorphic adenoma (CXPA) is an unusual epithelial malignancy that develops from a primary or recurrent pleomorphic adenoma (PA), the most common tumor of salivary glands, and constitutes about 11.5% of all carcinomas that affect these glands. Intraoral minor salivary glands and seromucous glands of the oropharynx are uncommon locations of CXPA. On histopathological examination, the tumor comprises a wide morphological spectrum with a variable proportion between the benign and malignant components with the latter often predominating and overlapping the PA, which may cause misdiagnosis. Here, we report a case of palatal minor salivary gland CXPA composed of invasive micropapillary salivary duct carcinoma and adenoid cystic carcinoma components with multiple nodal metastases in a 74-year-old woman. Neoplastic cells showed heterogeneous immunohistochemical profile with both luminal and myoepithelial differentiation. The invasive micropapillary salivary duct carcinoma component demonstrated overexpression of the oncoprotein human epidermal growth factor receptor-2. This feature should be considered and evaluated as a possible target for adjuvant therapy in case of metastatic disease.

Carcinoma ex pleomorphic adenoma of the upper lip: a case of an unusual malignant component of squamous cell carcinoma

Background

Squamous cell carcinoma (SCC) as the malignant component of carcinoma ex pleomorphic adenoma (CXPA) occurring in upper lip is rare.

Case report

A 55-year-old male patient presented with an asymptomatic mass of the upper lip that had noticed 8 years previously. The mass was clinically suspected to be a benign salivary gland tumor based on palpation and magnetic resonance imaging findings. A needle biopsy was then carried out, and the pathological diagnosis was pleomorphic adenoma. The tumor was removed under general anesthesia. Histopathological examination revealed well-demarcated tumor tissues showing typical histologic features of pleomorphic adenoma. However, SCC tissue with several mitotic figures was found in the central area of the tumor tissue. The tumor was finally diagnosed as CXPA. There was no evidence of recurrence or metastasis 6 years postoperatively.

Conclusion

This is the first report of CXPA of the upper lip with an unusual malignant component of SCC.

Pleomorphic adenoma of the buccal salivary gland: magnetic resonance imaging findings with differential diagnoses

The majority of minor salivary gland tumors are malignant. Of the benign tumors, pleomorphic adenomas are most common. The cheeks, lips, and gingiva are rarely sites of occurrence. A case of pleomorphic adenoma of the buccal salivary gland is presented here with a discussion of the importance of magnetic resonance imaging in demonstrating the extent of the lesion and establishing a differential diagnoses.

Carcinoma ex pleomorphic adenoma: a comprehensive review of clinical, pathological and molecular data

Carcinoma ex pleomorphic adenoma (Ca ex PA) is a carcinoma arising from a primary or recurrent benign pleomorphic adenoma. It often poses a diagnostic challenge to clinicians and pathologists. This study intends to review the literature and highlight the current clinical and molecular perspectives about this entity. The most common clinical presentation of CA ex PA is of a firm mass in the parotid gland. The proportion of adenoma and carcinoma components determines the macroscopic features of this neoplasm. The entity is difficult to diagnose pre-operatively. Pathologic assessment is the gold standard for making the diagnosis. Treatment for Ca ex PA often involves an ablative surgical procedure which may be followed by radiotherapy. Overall, patients with Ca ex PA have a poor prognosis. Accurate diagnosis and aggressive surgical management of patients presenting with Ca ex PA can increase their survival rates. Molecular studies have revealed that the development of Ca ex PA follows a multi-step model of carcinogenesis, with the progressive loss of heterozygosity at chromosomal arms 8q, then 12q and finally 17p. There are specific candidate genes in these regions that are associated with particular stages in the progression of Ca ex PA. In addition, many genes which regulate tumour suppression, cell cycle control, growth factors and cell-cell adhesion play a role in the development and progression of Ca ex PA. It is hopeful that these molecular data can give clues for the diagnosis and management of the disease.