Benign and malignant salivary gland-type mixed XXXX of the lung. Clinicopathologic and immunohistochemical study of eight cases.

@entity1 @entity4264 @entity5 @entity2 @entity2277 @entity583
BACKGROUND: Primary @entity2 showing features of salivary gland-type @entity5 are extremely rare. METHODS: Eight @entity1 with primary @entity2 showing light microscopic and immunohistochemical features of salivary gland-type mixed @entity5 were studied. RESULTS: The @entity1 were six @entity1 and two @entity1 , ages 35-69 years (mean, 52.5 years). The @entity5 ranged from 2 to 16 cm in greatest diameter. In two @entity1 the lesions presented as polypoid endobronchial lesions obstructing the lumen; in another two @entity1 the lesions were found in close proximity or in continuity with a bronchus; in three @entity1 , the lesions presented as peripheral parenchymatous nodules unrelated to a bronchus; and in one @entity1 , the relationship to the bronchus could not be determined. Histologically, the lesions were biphasic, showing admixtures in varying proportions of epithelial elements containing a predominant myoepithelial cell population with a stromal component containing an abundant myxoid or focally chondroid matrix. Immunohistochemical studies showed strong positivity of the cells in the epithelial component with low molecular weight keratins (CAM 5.2), and to a lesser extent with broad spectrum keratin, actin, and @entity2277 antibodies. The cells also showed variable reactivity in the epithelial and nonepithelial elements with S-100 protein and glial fibrillary acidic protein. Six @entity5 were grossly and histologically benign; in two @entity1 , the @entity5 were larger, locally invasive, and showed more atypical histologic features. All @entity1 were treated with surgical excision. On follow-up, of the six @entity1 with histologically benign-appearing @entity5 , one was alive and well 6 years after surgery; another died 4 years after surgery of a second unrelated @entity5 ; one died during the immediate postoperative period of @entity583 ; and three have been lost to follow-up. In the two @entity1 with histologically atypical lesions, the @entity5 recurred and metastasized after 2 and 3 years, respectively, with one of them leading to death caused by widespread metastases and superior @entity4264 . CONCLUSIONS: Review of the literature and the findings in the current series indicate that salivary gland-type mixed @entity5 of the lung may present with a spectrum of histologic features and clinical behavior, ranging from benign to frankly malignant, similar to that observed for their salivary gland counterparts. Size of the lesion at the time of presentation, extent of local infiltration, and degree of mitotic activity appear to be the most reliable prognostic features of these @entity5 .
