Fine needle aspiration biopsy of epithelioid-mesenchymal neoplasm with PTCH1-GLI1 fusion: A case report.

Mesenchymal tumors harboring GLI1 gene fusions are a rare new entity that typically occur in the head and neck region of young to middle aged adults, with a particular predilection for the tongue. We report herein a case of epithelioid mesenchymal tumor with PTCH1-GLI1 gene fusion of the right submental region in an 82-year-old male never smoker. Ultrasound-guided fine needle aspiration (FNA) with concomitant core needle biopsy was performed. Cytology smears revealed a hypercellular, monotonous aspirate comprised of epithelioid to plasmacytoid cells with round regular nuclei and moderate amounts of cytoplasm. There were admixed granulomata. The patient underwent surgical resection with limited neck dissection and subsequent pathologic examination with performed next generation sequencing confirmed the presence of epithelioid mesenchymal tumor with PTCH1-GLI1 gene fusion. To our knowledge, this is the first reported example of a mesenchymal tumor harboring GLI1 gene fusion initially evaluated by FNA.