Sinonasal teratocarcinosarcoma (SNTC) is a rare, aggressive, histologically heterogeneous
neoplasm of the paranasal sinuses and nasopharnyx of adults that is composed of variably benign or malignant neuroepithelial, epithelial, and mesenchymal elements. Occasional cases show intracranial extension and may be operated on by neurosurgeons and encountered by neuropathologists who may not be familiar with the entity. STNCs have not previously been associated with functional hypersecretory status. We report a 59-year-old male who presented with
headache and syndrome of inappropriate secretion of
antidiuretic hormone (
SIADH) and was subsequently found to have a bulky
tumor of the frontal and ethmoid sinuses with focal dural invasion. The
tumor was predominantly composed of
olfactory neuroblastoma areas (90% of
tumor) admixed with unusually well-developed
craniopharyngioma-like mature squamous epithelium and ghost cells ( 10% of
tumor). Scattered
neuroblastoma tumor cells showed strong immunoreactivity with
antibodies to
arginine vasopressin, supporting
ectopic hormone secretion by the
tumor. While the coexistence of neuroectodermal and oral ectodermal-like differentiation in SNTCs is characteristic, in our case it was developed to an extreme functional and morphologic degree and was unassociated with other mesenchymal or epithelial elements often found in these complex
tumors. SNTCs with limited differentiation have prompted controversy in classification.