Sinonasal teratocarcinosarcoma with rhabdoid features

Area of Science:

• Oncology
• Pathology

Background:

• Sinonasal teratocarcinosarcoma (SNTCS) is an exceptionally rare tumor originating in the nasal cavity and paranasal sinuses.
• The rhabdoid phenotype is associated with aggressive tumor behavior, but has not been previously documented in SNTCS.

Observation:

• A 46-year-old male presented with a month of left nasal obstruction.
• Imaging revealed a tumor involving the left nasal cavity, ethmoid sinus, ethmoid bone, and extending to the frontal lobe.
• The tumor exhibited diverse histopathological elements, including benign and malignant epithelial, mesenchymal, neural, and immature components.

Findings:

• The SNTCS displayed diffuse sheets of rhabdoid cells.
• Immunohistochemistry confirmed rhabdoid cell positivity for vimentin, nestin, neuron-specific enolase, and INI1.
• Ultrastructural analysis revealed paranuclear aggregates and whorls of intermediate filaments within the rhabdoid cells.

Implications:

• This case represents the first documented instance of rhabdoid features in SNTCS.
• The tumor presented at an advanced stage with rapid recurrence following initial treatment.
• The presence of the rhabdoid component is strongly suspected to be the driver of the observed aggressive clinical behavior.