Background: Inflammatory, hemorrhagic or tumoral laryngeal mass lesions can be found, but some of these lesions can be very rare, which makes the diagnosis a real challenge. Case presentation: We report a case of a laryngeal/hypopharynx lesion in a 69-year-old man with a submucosal bulging in the right piriform sinus. The only notable symptom was a mild foreign body sensation. CT scan confirms the presence of an expansive lesion, with lobulated contours, cystic/ with necrosis, comprising the right lateral wall of the hypopharynx, involving the piriform sinus circumferentially. Differential diagnosis with schwannoma, paraganglioma, hemangioma or other rare laryngeal lesions has to be made. Conclusion: In this case, the option for the diagnostic tool was excisional biopsy using an intralaryngeal approach. Histologic results showed a nodular fragment with hyaline replacement and central cavitation, with hematic fibrin clots, suggesting a clot/thrombus.

Keywords: thrombus; larynx; laryngeal mass; vascular event; case report.