Computed Tomographic Features of Basihyoid Ectopic Thyroid Carcinoma in Dogs

Abstract

Eight dogs with a firm, nonpainful swelling in the ventral laryngeal region and with a final diagnosis of ectopic thyroid carcinoma were investigated by Computed Tomography (CT) at six different institutions. Computed Tomography findings were reviewed, focusing on lesion volume, shape, margins, relationship with surrounding structures and adjacent vessels, attenuation characteristics, and presence of metastases. Ectopic thyroid carcinomas were seen as oval-to-bilobed masses centered on the basihyoid bone with associated bone lysis, highly vascularized capsules with central poorly contrast enhancing areas. In all cases there was laryngeal wall infiltration, in two dogs invasion of the laryngeal lumen and in one case invasion of the ventral muscular and subcutaneous plane. Metastases were found in retropharyngeal lymph nodes (three cases) and in the lung (two cases). Ectopic thyroid carcinoma should be considered in the differential diagnosis when a mass in the basihyoid region is present. Described CT features may be typical for ectopic thyroid neoplasia and could be used to help decide the therapeutic plan.

Computed tomographic appearance of canine thyroid tumours

“…This study, the study by Taeymans et al () and a further study by Rossi et al () described ectopic thyroid carcinomas located at midline, ventral to the hyoid apparatus. This appears to be a location where neoplastic transformation of ectopic thyroid can occur.…”

Clinical Features and Treatment Outcomes of 41 Dogs with Sublingual Ectopic Thyroid Neoplasia

“…Contrast‐enhanced computed tomography (CT) has been described as a highly specific way to distinguish thyroid tumors from other cervical masses, and CT is a more sensitive modality to detect pulmonary metastatic nodules than conventional radiography . Recently, the CT characteristics of 8 dogs with ectopic sublingual thyroid carcinoma were reported; in that study, these tumors were associated with severe lysis of the basihyoid bone, with infiltration of the laryngeal wall or laryngeal lumen, sometimes with metastasis. Based on these characteristic features, it was concluded that CT is strongly indicated for evaluation of dogs with cranioventral cervical masses, as CT identifies the most probable origin of the tumor and can be used for treatment planning .…”

“…Recently, the CT characteristics of 8 dogs with ectopic sublingual thyroid carcinoma were reported; in that study, these tumors were associated with severe lysis of the basihyoid bone, with infiltration of the laryngeal wall or laryngeal lumen, sometimes with metastasis. Based on these characteristic features, it was concluded that CT is strongly indicated for evaluation of dogs with cranioventral cervical masses, as CT identifies the most probable origin of the tumor and can be used for treatment planning . While there is no doubt that use of CT has facilitated the diagnosis and staging of head and neck tumors, there are potential problems with the routine use of CT for evaluation dogs with thyroidal neoplasia.…”

“…Almost all reported cases in dogs, however, represent ectopic thyroid tumors arising in the cranial mediastinal, heart base locations, or both . In contrast, there are only a small number of reported dogs with ectopic thyroid neoplasia arising in the lingual or sublingual location, and neither the prevalence nor clinical characteristics of ectopic thyroid tumors arising in this location have been described. The aim of this study was to describe the clinical features, treatment, and outcomes of 41 cases of ectopic sublingual thyroid neoplasia in dogs.…”

Behandlung eines ektopen Schilddrüsentumors mit Invasion des Zungenbeins

“…Das computertomografische Erscheinungsbild von ektopen Schilddrüsentumoren wurde in einer Studie von 2013 ausführlich beschrieben [9]. Bei allen 8 Fällen dieser Studie, wie auch in diesem Fallbericht, zeigte sich der Tumor als heterogene Umfangsvermehrung, sowohl vor als auch nach der Kontrastmittelgabe.…”