Salivary gland anlage tumor of the nasopharynx: a clinicopathologic and immunohistochemical study of three cases.

ABSTRACT

The histologic and immunohistochemical features of three congenital pedunculated nasopharyngeal midline masses are reported. The follow-up in all cases was uneventful. The tumors were characterized by solid and cystic squamous nests and ductlike structures focally continuous with the surface squamous mucosa of the tumor. Most of epithelial structures coalesced with densely cellular stroma-like nodules. Immunoperoxidase staining showed the presence of epithelial markers in both spindle cells and epithelial structures. Spindle cells were also reactive to vimentin and smooth muscle actin, revealing their myoepithelial phenotype. Based on these observations, a diagnosis of salivary gland anlage tumor, also called congenital pleomorphic adenoma of the nasopharynx, was made. The similarity of these tumors' architecture and cellular composition to the normally developing salivary gland has led to the hypothesis of a tumorlike, hamartomatous lesion developing in a site in which minor salivary gland tissue occurs. This report reviews 12 identified cases of this tumor, of which all but one (in which the patient died of sepsis) had a favorable outcome. In an infant with respiratory distress and/or feeding difficulties, these tumors must be differentiated from other midline masses such as encephaloceles and teratomas. They appear curable by surgical exeresis only.