Osteoradionecrosis of the hyoid bone: imaging findings

Abstract

Background and purpose: ORN is a postradiation complication that has been well-documented in the medical literature. Most cases in the head and neck have been described in the mandible or larynx. Only a handful of cases in the hyoid bone are documented, all in the clinical literature. Our purpose is to present the clinical and imaging features of ORN involving the hyoid bone.

Materials and methods: We present a case series of 13 patients with imaging findings highly suggestive of hyoid ORN after radiation therapy for head and neck cancers, in which we observed progressive features of hyoid disruption along with adjacent soft-tissue ulceration.

Results: Pretreatment imaging, when available, showed a normal hyoid. Typical postradiation imaging findings included an initial tongue base ulcerative lesion with air approaching the hyoid bone, and subsequent observation of hyoid fragmentation, often with intraosseous or peri-hyoid air and the absence of associated mass-like enhancement.

Conclusions: Findings of hyoid fragmentation, cortical disruption, and soft tissue or intraosseous air in the postradiation therapy patient should strongly suggest the diagnosis of hyoid ORN. It is important recognize this entity because the diagnosis may preclude potentially harmful diagnostic intervention and allow more appropriate therapy.

Fig 1.

Patient 4. A 64-year-old man radiated for squamous cell carcinoma of the left lateral oropharyngeal wall. A, CT examination with contrast obtained before radiation therapy shows the lower aspect of the lesion in the vallecula, lying adjacent to the hyoid bone (arrow). There is a nodal metastasis in the left neck (arrowhead), also adjacent to the hyoid. B and C, Axial contrast-enhanced CT images obtained 5 months following treatment with 70 Gy show a defect in the lateral pharyngeal wall (arrow, B) and an exposed piece of hyoid (arrow in C). At this time, the hyoid was otherwise intact. D, CT bone window on follow-up imaging shows a missing resorbed hyoid.

Fig 2.

Patient 10. A 67-year-old man after radiation therapy at an outside hospital for base-of-tongue cancer. A and B, Axial contrast-enhanced CT scans show an air-filled soft-tissue defect in the left posterior tongue (arrow, A). Lower down, this communicates with the hyoid (B). There is an unrelated nodal recurrence in the right neck (arrowhead, A). B, Soft-tissue CT image more inferiorly shows air (arrowheads) and fluid (arrows) surrounding the hyoid. C, CT bone window shows intraosseous air (arrowheads) and a hyoid fracture (arrow).

Fig 3.

Patient 9. A 70-year-old man previously radiated for base-of-tongue carcinoma and subsequently re-irradiated for neck recurrence. A, Contrast-enhanced CT examination 6 months after the completion of the second course of radiation demonstrates an air-filled necrotic cavity in the tongue base without surrounding enhancement (arrow). B, CT image more inferiorly shows that the cavity contains fluid and internal air bubbles (arrow, B) and is in close contact with the hyoid. The hyoid was reported as being at risk for ORN. C, CT bone window obtained 2 months after B reveals that the hyoid is now fragmented (arrow).

Fig 4.

Patient 3. A 66-year-old man status post 60 Gy for treatment of metastatic squamous cell carcinoma to the left neck, primary unknown, who subsequently developed a primary malignancy in the right oropharyngeal wall, for which an additional dose of 50.2 Gy was administered. A, CT bone window before XRT shows an intact hyoid. B and C, Contrast-enhanced CT, soft-tissue and bone windows, respectively, 5 months following completion of the second course of XRT. There is an enhancing process surrounding the right side of the hyoid (arrows, B) and an exposed fragment of hyoid surrounded by air (arrowhead, B and C). Hyoid fractures can be seen (arrow in C). D, Contrast-enhanced CT image 5 months after B and C shows dramatically increased enhancement extending to the left of midline (arrows). Because of these findings and relentless aspiration, a total laryngectomy was performed; at histologic examination, there was only necrosis and inflammation.

Fig 5.

Patient 1. A 67-year-old man, 34 months following an unknown dose of XRT at an outside facility for treatment of squamous cell carcinoma of the tongue base. A, Axial bone window CT scan shows typical fragmentation and intraosseous air characteristic of hyoid ORN. B, PET/CT, obtained concurrent to A, demonstrates intense focal FDG uptake (SUV=7.5), which was regarded as suspicious for tumor. The patient was offered hyoidectomy but refused, and his symptoms of dysphagia and odynophagia gradually improved with hyperbaric O₂ during the follow-up period of 14 months, after which the patient was lost to follow-up.