SALIVARY-GLAND ANLAGE TUMOR (CONGENITAL PLEOMORPHIC ADENOMA) - A CLINICOPATHOLOGICAL, IMMUNOHISTOCHEMICAL AND ULTRASTRUCTURAL-STUDY OF 9 CASES

Salivary gland anlage tumor (SGAT) is a polypoid lesion of the nasopha rynx that presents with respiratory distress at birth or within the fi rst few days or weeks of life. Among our nine cases, there was a male predilection (7M:2F). All tumors were in the midline and attached to t he posterior pharyngeal wall by a delicate pedicle. The largest tumor measured 3 cm. A biphasic histologic pattern of squamous nests and duc t-like structures at the periphery blended into solid, predominantly m esenchymal-appearing nodules centrally. The surrounding submucosal man tle of epithelial structures was consistently immunoreactive for cytok eratin and epithelial membrane antigen, whereas the stromal-like cells of the central nodules showed variable immunopositivity for cytokerat in, vimentin, and muscle-specific actin. Both components were equally reactive for salivary gland amylase. Ultrastructurally, some of the st romal-like cells had features of myoepithelial cells. The histologic a nd architectural features of SGAT are similar in some respects to the developing salivary gland. It is proposed that the SGAT is a probable hamartoma of minor salivary gland derivation whose origin in the nasop harynx is potentially life-threatening in an infant.