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Primary Pleural Malignant Mesothelioma with Delayed Metastasis to the Piriform Sinus: Report of a Case

Piriform sinus tumors are uncommon and silent lesions. Their prognosis is poor because these tumors are usually not detected until they have reached an advanced stage. Almost all piriform sinus cancers are primary squamous cell carcinomas; other primary and metastatic tumors of the hypopharynx are exceedingly rare. One of the rare tumors in the laryngopharyngeal area is sarcomatoid carcinoma, which is an unusual type of squamous cell carcinoma. Another uncommon malignant tumor that is histologically similar to sarcomatoid carcinoma is malignant mesothelioma, which is a rare form of lung carcinoma. The macroscopic appearance and histologic characteristics of sarcomatoid carcinoma and malignant mesothelioma are so similar that differentiation is usually achieved by immunohistochemical examination. To the best of our knowledge, no case of primary or metastatic laryngohypopharyngeal malignant mesothelioma has been previously reported in the literature. In this article, we describe a case of isolated malignant mesothelioma of the piriform sinus that resembled a sarcomatoid carcinoma in a 50-year-old man with a history of lung mesothelioma.