Thyroid hemiatrophy associated with papillary thyroid carcinoma.

Purpose: The present study aimed to investigate CT imaging features, pathological findings, and prognosis in patients with thyroid hemiatrophy (THA) associated with papillary thyroid carcinoma (PTC).

Methods: This retrospective study included 225 patients with histopathologically proven PTC treated by surgical resection who underwent preoperative CT scanning. On CT images, THA was defined as thyroid parenchymal hemiatrophy on the ipsilateral side of PTC. CT findings, overall survival, and disease-free survival were compared between patients with and without THA. Pathological findings were also assessed in PTCs with and without THA.

Results: THA was observed in 35 of 225 (16%) patients with PTC. Atrophic thyroid parenchyma was observed in the right lobe of 20 patients (57%) and in the left lobe of the remaining 15 patients (43%). With respect to the solid components within PTCs, contrast-enhanced CT attenuation (114.2 ± 18.2 vs. 126.7 ± 31.3 HU; p < 0.05) and CT attenuation change for contrast-enhanced CT minus unenhanced CT (60.2 ± 18.1 vs. 72.3 ± 31.0 HU; p < 0.05) were significantly lower in PTCs with THA than in those without THA. Histopathologically, almost all PTCs with THA (97%) had keloid-like collagen, which is broad bundles of hypocellular collagen with bright eosinophilic hyalinization, typically observed in keloid. However, no significant differences were observed in the prognosis between the two groups.

Conclusion: THA was occasionally observed in patients with PTC. Weak contrast-enhancement was distinct characteristic of PTC patients with THA, which is probably caused by keloid-like collagen.