[1146] A Histologic and Immunohistochemical Study of High-Grade Non-Intestinal Sinonasal Adenocarcinomas

EB Stelow, VY Jo, SE Mills, DL Carlson. University of Virginia, Charlottesville, VA; Memorial Sloan-Kettering Cancer Center, New York, NY

Background: The WHO currently classifies sinonasal adenocarcinomas (SNACs) that do not resemble typical salivary gland tumors as intestinal or non-intestinal. Non-intestinal SNACs are then further classified as low or high grade based on cellular pleomorphism, mitotic activity and necrosis. Non-intestinal SNACs are somewhat poorly characterized and high-grade non-intestinal (HGNI) SNACs have been only rarely reported. Here we review our experience with these tumors.
Design: The surgical pathology files of two institutions were reviewed for all SNACs. Cases were reviewed and all tumors better classified as salivary gland-type tumors, intestinal-type SNACs (based on histology and / or immunohistochemistry (IHC)) and low-grade non-intestinal SNACs were removed. We recorded all clinical and histologic features. Previous IHC results were noted and additional IHC was performed in select cases.
Results: Twenty-five cases of HGNI SNACs were identified from 20 men and 5 women. Ages ranged 19 to 83 yrs (mean=54.5; median=60). Ten cases involved the nasal cavity and sinuses, 9 involved the nasal cavity only and 6 involved the sinuses only. Surface involvement by tumor was seen in 64% of cases and 24% of cases were associated with Schneiderian papillomas. Many cases were solid and trabecular with occasional small cystic spaces, composed of neoplastic cells with a small amount of amphiphilic cytoplasm. Occasional cases were more nested and composed of larger cells, with more abundant eosinophilic cytoplasm (somewhat akin to salivary duct carcinomas). Most cases had marked cytologic and nuclear pleomorphism, abundant mitotic activity and necrosis, however, these features were not uniform. Tumors lacked CDX2 and CK20 immunoreactivity (aside from rare CK20 immunoreactive cells). Diffuse, strong CK7 immunoreactivity was seen in 43% of cases. S100, p63 and neuroendocrine antigen reactivity were only seen in rare cells in occasional cases.
Conclusions: High-grade non-intestinal SNACs are more common in men and, although they occur over a wide age range, they are much more common in older individuals. Histologically, they show a great deal of heterogeneity, however, the majority appear solid and trabecular and have small cystic spaces. Surface involvement is common and their association with Schneiderian papillomas raises the possibility that the tumors develop from the surface epithelium. Immunohistochemically, the tumors do not show intestinal or myoepithelial differentiation.
Category: Head & Neck

Tuesday, March 10, 2009 1:00 PM

Platform Session: Section H, Tuesday Afternoon