Sanded nuclei in hepatitis B: eosinophilic inclusions in liver cell nuclei due to excess in hepatitis B core antigen formation.

In confirmation of earlier descriptions by Huang et al. (Huang S-N, Millman I, O'Connell A, Aronoff A, Gault H, Blumberg BS: Am J Pathol 67: 453, 1972) nuclear eosinophilic inclusions due to excess HBcAg particles have been identified in cases of chronic hepatitis B virus infection. As the euchromatin space of affected nuclei is "sanded" by numerous core particles with concomitant dissolution of the chromatin network, spiky, finely granular, and eosinophilic inclusions without a limiting membrane become visible in hematoxylin and eosin-stained paraffin sections. These HBcAg inclusions stain greyish pink with chromotrope aniline blue and are negative for orcein, the periodic acid-Schiff reaction, and the Feulgen reaction for DNA. Sanded nuclei were detected, although not always and only few in number, exclusively in HBAg-positive patients when a focal (as in chronic aggressive hepatitis) or a generalized core formation (as in immunosuppressed kidney transplant recipients) could be demonstrated by electron microscopy or immunofluorescence. Therefore, the positive finding of sanded nuclei in a persistent hepatitis B virus infection indicates an excessive core formation the extent of which should be verified by specific methods.