90Y-TheraSpheres: The New Look of Yttrium-90

Area of Science:

• Radiology and Nuclear Medicine
• Surgical Pathology
• Oncology

Background:

• Selective internal radiation therapy (SIRT) using Y-TheraSphere and Y-SIRSphere is a treatment for unresectable liver malignancies.
• Y-TheraSphere microspheres have distinct histologic features.
• This is the first reported series of Y-TheraSpheres identified in surgical pathology specimens.

Purpose of the Study:

• To describe the histologic characteristics of Y-TheraSpheres.
• To report the identification of Y-TheraSpheres in hepatectomy specimens from patients treated for hepatocellular carcinoma (HCC).
• To highlight the importance of recognizing Y-TheraSpheres for diagnosis.

Main Methods:

• Histologic examination of 15 hepatectomy specimens from patients treated with Y-TheraSphere.
• Review of surgical pathology specimens for microsphere identification.
• Prospective identification of Y-TheraSpheres gastritis in a separate case.

Main Results:

• Y-TheraSpheres were identified in 15 hepatectomy specimens from four centers.
• Microspheres were colorless, 20-30 μm, with occasional internal bulls'-eye or cross structures.
• One case of Y-TheraSpheres gastritis was identified.

Conclusions:

• Recognition of Y-TheraSpheres is important for considering nearby malignancy or radiation injury.
• Y-TheraSpheres can be distinguished from Y-SIRSphere by their colorless appearance and specific internal structures.
• A history of HCC and background radiation changes are clues to diagnosis.