Solitary Fibrous Tumor of the Larynx—CO 2 Laser Excision With Arterial Embolization

Solitary fibrous tumor (SFT) is a rare mesenchymal neoplasm that typically appears as a pleura-based mass despite the recent recognition of its extrapleural location ^1,2 These tumors have been described in other locations including the mediastinum, head and neck, orbit, and urogenital system. ^{1 –4} Only 3 cases of SFT arising from the larynx have been reported in the English literature. ³ We describe a new case of laryngeal SFT localized at the right aryepiglottic fold (AEF). A 35-year-old man presented with a 6-month history of foreign body sensation in the throat, but not voice problem. Computed tomography images revealed a well-defined mass, 1.6 × 2.3 × 3.5 cm, well lobulated, enhancing mass, on the right AEF (Figure 1A and B). There was no destruction of surrounding structures including the thyroid cartilage. External carotid angiography demonstrated a supraglottic, hypervascular tumor. The tumor vessels originated from the superior thyroid artery and were embolized with complete occlusion (Figure 1C and D). The tumor was removed by transoral CO₂ laser surgery using suspension laryngoscopy. Endoscopically, the mass was a large, well-defined supraglottic tumor without signs of infiltration (Figure 2A). An excised specimen (Figure 2B) showed moderate cellularity, mild to moderate atypia, and no necrosis. The definitive diagnosis was obtained by immunohistochemical analysis that showed fibrosis and ovoid to spindle-shaped tumor cells (H&E stain, original magnification ×200; Figure 2C). The tumor cells show strong immunoreactivity to CD34 (original magnification ×200; Figure 2D). The patient remains free of tumor after 11 months of follow-up.

Figure 1.

Computed tomography demonstrates a well-defined mass at the right aryepiglottic fold (A; axial, B; sagittal). Arterial angiography before embolization (C), supraglottic hypervascular tumor, and after embolization (D), successful with complete occlusion.

Figure 2.

Solitary fibrous tumor on the right aryepiglottic fold (A) and excised specimen (B). The tumor shows fibrosis and the tumor cells are ovoid to spindle shape (H&E stain, original magnification ×200) (C). The tumor cells show strong immunoreactivity to CD34 (original magnification ×200) (D).

The histogenesis of SFT has been controversial, but findings of a recent immunohistochemical and ultrastructural analysis have strongly suggested of origin from submesothelial mesenchymal fibroblast-like cells, rather than epithelial tissue. ^1,2 Solitary fibrous tumor is composed mainly of spindle cells arranged in no specific pattern that form a hard encapsulated mass usually with mild atypia and rare mitoses. Immunohistochemically, CD34 is a transmembrane glycoprotein found on the surface of hematopoietic progenitor cells that has recently been considered a positive marker for SFT. ³ Although CD34 is not specific for these tumors, the expression of CD34, in conjunction with lack of expression of other immunohistochemical markers, can be helpful in excluding a variety of soft tissue tumors. Solitary fibrous tumors of the head and neck seem to be mostly benign and can be treated successfully with surgical excision. ^3,4 To our knowledge, this case is the first laryngeal SFT that has been resected by transoral CO₂ laser surgery after embolization of feeding vessels.