Mucinous and Squamous Metaplasia in Benign Tumors of the Parotid Gland: A Potential Pitfall in the Diagnosis

Hamdan, Kasem; Maly, Bella; Elashar, Ron; Gross, Menachem

doi:10.1016/j.otohns.2005.01.020

Cited by 10 publications

(8 citation statements)

References 3 publications

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“…Focal squamous metaplasia, probably related to ischemia 16 , may be present in about 25% of the PA 24 . The cases of PA presenting extensive keratin-filled cysts lined by squamous epithelium are referred to in the literature as "cystic PA with extensive adnexa-like differentiation", since the histologic features mimic cutaneous appendages 7 , 25 .…”

Section: Discussionmentioning

confidence: 99%

“…Extensive squamous metaplasia in PA, especially in the absence of chondromyxoid stroma, can mistakenly lead to a diagnosis of benignity, such as choristoma 24 or keratocystoma 21 , and malignancy 13 , including mucoepidermoid carcinoma (MEC) and squamous cell carcinoma, especially when sampling the tissue by fine-needle aspiration biopsy (FNAB) and incisional biopsy, due to limited and selective sampling 5 , 7 , 12 , 16 , 26 . It is important to discuss the diagnostic pitfall of this unusual presentation of a common benign entity, particularly the differential diagnosis with these malignant lesions.…”

Section: Discussionmentioning

confidence: 99%

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Pleomorphic adenoma with extensive squamous metaplasia and keratin cyst formations in minor salivary gland: a case report

Goulart¹,

Freitas-Faria²,

Goulart³

et al. 2011

J. Appl. Oral Sci.

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Pleomorphic adenoma (PA), the most common salivary gland tumor, accounts for 54 to 65% of all salivary gland neoplasias and 80% of the benign salivary gland tumors. It most frequently affects the parotid gland, followed by the submandibular and the minor salivary glands. Microscopically, mucous, sebaceous, oncocytic and squamous metaplasia, sometimes with the formation of keratin pearls, may be present, but the latter rarely results in the formation of extensive keratin-filled cysts lined by squamous epithelium. Extensive squamous metaplasia can be mistaken for malignancy, including mucoepidermoid carcinoma and squamous cell carcinoma. Here, we present an unusual case of PA with extensive squamous metaplasia and keratin cyst formations in a minor salivary gland, and discuss its microscopic features, including the immunohistochemical characteristics, and differential diagnosis of this uncommon presentation.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Pleomorphic adenoma with extensive squamous metaplasia and keratin cyst formations in minor salivary gland: a case report

Goulart¹,

Freitas-Faria²,

Goulart³

et al. 2011

J. Appl. Oral Sci.

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“…3–6 Squamous cell metaplasia has been reported as a potential pitfall in fine-needle aspiration cytology (FNAC) of pleomorphic adenoma, which can be confused with a squamous cell or mucoepidermoid carcinoma. Different hypotheses have been advanced for its etiopathology.…”

Section: Discussionmentioning

confidence: 99%

Schwannoma-like pleomorphic adenoma of the parotid

Tille

Reychler²,

Hamoir³

et al. 2011

Rare Tumors

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Pleomorphic adenoma is the most common benign salivary gland tumour. It can occur in any salivary gland, but is most frequently found in the parotid gland. Chondroid metaplasia is a frequent finding in pleomorphic adenoma. Other forms of metaplasia have been described, but are encountered less frequently. We report a rare case of unusual pleomorphic adenoma of the parotid gland with schwannoma-like feature.

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“…In a case report by Hamdan et al , a misdiagnosis of mucoepidermoid carcinoma was made on frozen section. [ 9 ]…”

Section: Discussionmentioning

confidence: 99%

Pleomorphic adenoma with squamous and appendageal metaplasia mimicking mucoepidermoid carcinoma on cytology

et al. 2008

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Background:Histological diversity is the hallmark of pleomorphic adenoma, the most common salivary gland tumor. It may cause difficulty in cytological interpretation, due to limited and selective sampling.Case presentation:A 16-year-old female patient presented with right cheek swelling. Fine needle aspiration cytology showed squamous cells, basaloid cells, and foamy cells, along with extracellular keratin and foreign body giant cells. Characteristic metachromatic fibrillary chondromyxoid stroma, which is usually seen in pleomorphic adenoma, was not seen in the aspirate. A diagnosis of mucoepidermoid carcinoma was given on cytology. Subsequent resection revealed an encapsulated pleomorphic adenoma, with extensive squamous metaplasia and appendageal differentiation on histology.Conclusion:This case illustrates that pleomorphic adenoma with squamous metaplasia presents a potential for misinterpretation as mucoepidermoid carcinoma on cytology. We discuss the various pitfalls and the features that are helpful in distinguishing these two lesions.

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Mucinous and Squamous Metaplasia in Benign Tumors of the Parotid Gland: A Potential Pitfall in the Diagnosis

Cited by 10 publications

References 3 publications

Pleomorphic adenoma with extensive squamous metaplasia and keratin cyst formations in minor salivary gland: a case report

Pleomorphic adenoma with extensive squamous metaplasia and keratin cyst formations in minor salivary gland: a case report

Schwannoma-like pleomorphic adenoma of the parotid

Pleomorphic adenoma with squamous and appendageal metaplasia mimicking mucoepidermoid carcinoma on cytology

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