Multiparametric Ultrasound Features of the Diffuse Sclerosing Variant of Papillary Thyroid Carcinoma: A Single-Center Case Series

<b>Background/Objectives:</b> The diffuse sclerosing variant of papillary thyroid carcinoma (DSV-PTC) is a rare and aggressive subtype characterized by diffuse gland involvement and early cervical lymph node metastasis. Preoperative differentiation from classic papillary thyroid carcinoma and autoimmune thyroid disease remains challenging on B-mode ultrasound. This study aimed to describe the multiparametric ultrasound features of DSV-PTC in a single-center case series and highlight practical imaging insights. <b>Methods:</b> We retrospectively reviewed seven consecutive patients with histologically confirmed DSV-PTC evaluated at a single center between 2013 and 2025. All patients underwent standardized B-mode ultrasound, color Doppler, and two-dimensional shear-wave elastography prior to surgery. Clinical, autoimmune, cytological, surgical, pathological, and follow-up data were analyzed descriptively. <b>Results:</b> The cohort included five females and two males (mean age 28 years). Autoimmune thyroid disease was present in three patients. High-risk ultrasound features were identified in all cases, with microcalcifications in six patients and a diffuse "snowstorm" appearance in five. Elastography demonstrated increased stiffness in six out of seven lesions (Emean 28-173 kPa; Emax 31-300 kPa). Cervical lymph node metastases were confirmed in all patients. In two cases, elastography aided identification of focal malignant involvement within diffusely altered thyroid parenchyma. All patients underwent total thyroidectomy with central neck dissection; lateral neck dissection and radioiodine therapy were performed selectively. No distant metastases were detected. <b>Conclusions:</b> In this case series, DSV-PTC showed a characteristic multiparametric ultrasound pattern combining high-risk B-mode features with frequently increased tissue stiffness. Elastography provided complementary information, particularly in the presence of autoimmune thyroid disease, by helping localize focal malignant involvement within diffusely altered parenchyma.