Which lesion is described as a 'Stealth lesion' and is usually solitary, less than 5 cm?

Which lesion is described as a 'Stealth lesion' and is usually solitary, less than 5 cm?

• A. FNH
• B. Hemangioma
• C. Infantile Hemangioendothelioma
• D. Kasabach-Merritt Syndrome

Answer: (A)

A stealth lesion is a nodule that blends with the normal liver on ultrasound—usually isoechoic and without distinct features that clearly separate it from surrounding parenchyma. Focal nodular hyperplasia often fits this description. It tends to be small and solitary, typically under 5 cm, and can appear as a well-defined, iso- to mildly hypoechoic lesion that resembles liver tissue on gray-scale imaging. Because its ultrasound appearance is subtle and lacks a unique hallmark on gray-scale, it may be easy to overlook unless other imaging phases or modalities reveal its character. The central scar and distinctive vascular pattern are often better seen on CT or MRI, not on ultrasound, which is why FNH is commonly described as stealth. In contrast, a hepatic hemangioma usually presents with a more clearly recognizable pattern on ultrasound (often very bright, well-circumscribed on gray-scale and shows characteristic Doppler features) and is less typically described as stealth. Infantile hemangioendothelioma occurs in infants rather than adults and tends to be multifocal or diffuse. Kasabach-Merritt syndrome refers to a coagulopathy associated with certain vascular tumors in infants, not a solitary small lesion with the ultrasound stealth appearance.

A stealth lesion is a nodule that blends with the normal liver on ultrasound—usually isoechoic and without distinct features that clearly separate it from surrounding parenchyma. Focal nodular hyperplasia often fits this description. It tends to be small and solitary, typically under 5 cm, and can appear as a well-defined, iso- to mildly hypoechoic lesion that resembles liver tissue on gray-scale imaging. Because its ultrasound appearance is subtle and lacks a unique hallmark on gray-scale, it may be easy to overlook unless other imaging phases or modalities reveal its character. The central scar and distinctive vascular pattern are often better seen on CT or MRI, not on ultrasound, which is why FNH is commonly described as stealth.

In contrast, a hepatic hemangioma usually presents with a more clearly recognizable pattern on ultrasound (often very bright, well-circumscribed on gray-scale and shows characteristic Doppler features) and is less typically described as stealth. Infantile hemangioendothelioma occurs in infants rather than adults and tends to be multifocal or diffuse. Kasabach-Merritt syndrome refers to a coagulopathy associated with certain vascular tumors in infants, not a solitary small lesion with the ultrasound stealth appearance.