The correct answer is D: Mucoepidermoid carcinoma.
Discussion: Mucoepidermoid carcinomas, most often encountered in the salivary gland, are rare and unusual tumors of the lung. Primary salivary gland-type tumors of the lung represent a minor subset of lung tumors, accounting for no more than 1% of all pulmonary neoplasms. Of those, however, mucoepidermoid carcinomas are the most common.
It is highly important to separate this tumor from either adenocarcinoma or squamous cell carcinoma. Contrary to both of those two tumors, which belong to the non–small-cell carcinomas, the treatment of choice for low-grade mucoepidermoid carcinomas is complete surgical resection. It is important to separate low-grade mucoepidermoid carcinomas from high-grade mucoepidermoid carcinomas. In the high-grade variant, the tumor commonly shows mitotic activity and necrosis, which is not prominent in the low-grade variant. Also, high-grade tumors are usually followed by adjuvant treatment in addition to surgical resection.
The use of immunohistochemical markers in the diagnosis of these tumors is limited to epithelial markers, which may share similar immunophenotype with other non–small-cell carcinomas. However, the correct interpretation requires familiarity with these tumors.
The prognosis after complete surgical resection is excellent.
Tips for the diagnosis:
• Be suspicious of this tumor in the younger age population
• On histology, the admixture of epidermoid cells with mucus-secreting cells
1. Moran CA. Primary salivary gland type tumors of the lung. Sem Diagn Pathol. 1995;12:106-122.
2. Yousem SA, Hochholzer L. Mucoepidermoid tumors of the lung. Cancer. 1987;60:1346-1352.