Diagnostic imaging of parotid gland oncocytoma: a pictorial review with emphasis on ultrasound assessment.

Parotid gland oncocytoma (PGO) is a rare benign epithelial tumor that usually occurs in the elderly population. The most common clinical presentation is a painless, slow-growing, non-tender, lobulated, and mobile mass. Histologically, it is composed of monotonous sheets of epithelial cells (oncocytes) with a central scar. The cross-sectional appearance is not specific, and it overlaps with other parotid lesions. On ultrasound (US), oncocytoma appears as an ovoid, well-defined, homogeneous, and hypoechoic lesion. Cystic and hemorrhagic areas as well as intralesional fat may be observed. Doppler analysis shows intratumoral vessels, sometimes with a spoke-wheel pattern. The peak systolic flow is high (up to 100 cm/sec). Furthermore, oncocytoma is avid of FDG on a PET scan, as well as a malignant tumor. Thus, a combined clinical, imaging, and pathologic assessment is essential to establish the most accurate diagnosis and plan the best treatment. US, combined with Doppler techniques, can play an important role in suggesting the diagnosis and confirming it through percutaneous sampling. The purpose of this review is to show the imaging findings in PGO, with special emphasis on the US appearance.

Thyroglossal duct cysts and site-specific differential diagnoses: imaging findings with emphasis on ultrasound assessment.

Thyroglossal duct cysts (TGDCs) are the most common congenital abnormality of the neck, accounting for approximately 70% of congenital neck lesions. Two-thirds of thyroglossal duct anomalies are diagnosed within the first three decades of life, with more than half being identified before 10 years of age. The age of presentation, clinical examination and imaging are essential for an accurate diagnosis. This review aims to summarize the imaging findings of TGDCs and their main differential diagnoses with emphasis on ultrasound assessment. A focus on site-specific key differentiating between them is also addressed.