Thyroid gland after total laryngectomy: CT appearance.

PURPOSE

To determine the computed tomographic (CT) appearance of the normal thyroid gland after total laryngectomy, because the high attenuation (or heterogeneous attenuation) of thyroid parenchyma was misinterpreted as tumor on several CT studies.

MATERIALS AND METHODS

A search of computerized clinical files compiled from January 1996 through August 1997 yielded data on 24 patients who had undergone laryngectomy and subsequent CT of the neck. From these 24 patients, CT findings were available in 21. Because one patient had undergone total thyroidectomy and was excluded from the study, a retrospective review was performed in the remaining 20 patients.

RESULTS

In 14 patients, unilateral thyroid tissue was present; in the other six there was bilateral thyroid tissue not connected by an isthmus. Thus, there were 26 remaining thyroid lobes, of which six were round and 20 were oval or lobular. Nineteen lobes showed homogeneously high attenuation (including one scanned without use of contrast material), six showed heterogeneous high attenuation or contained areas of hyperlucency, and one was obscured by streak artifact.

CONCLUSION

Thyroid tissue can appear as unilateral or bilateral asymmetric masses on neck CT scans after laryngectomy. Gland tissue can show homogeneously or heterogeneously high attenuation. Familiarity with the varied postoperative appearance of normal thyroid gland can prevent its misdiagnosis as tumor.