Sinonasal teratocarcinosarcoma with rhabdoid features.

Sinonasal teratocarcinosarcoma (SNTCS) is a very rare tumor developed in the nasal cavity and paranasal sinuses. The rhabdoid phenotype represents an aggressive biological behavior, but the rhabdoid feature has hitherto not been reported in cases of SNTCS. A 46-year-old man complained of a 1-month history of left-sided nasal obstruction. Computed tomography scan and magnetic resonance imaging showed a tumor mass involving the left nasal cavity, ethmoid sinus, and ethmoid bone with extension to the left frontal lobe of the brain. A gross total resection of the mass was performed and postoperative radiation therapy administered. Seven weeks later, several recurring masses were detected in the left frontotemporal lobe of the brain. A gross total resection of the mass was performed and postoperative chemotherapy administered. Histopathologically, the tumor showed benign and malignant epithelial, mesenchymal, neural, and immature elements. In addition, diffuse sheets of rhabdoid cells were immunopositive for vimentin, nestin, neuron-specific enolase, and INI1. Ultrastructurally, rhabdoid cells showed paranuclear aggregates and whorls of intermediate filaments with a 9-10 nm diameter. In conclusion, we report first case of rhabdoid features in SNTCS. The present case showed an advanced stage and early recurrence; the rhabdoid component was probably responsible for this aggressive behavior.