The next two images show immunoperoxidase stains for light chains in a cellular area of the infiltrate. The positive cells have a brown cytoplasm. The light chain deposits were not differentially stained with the antibodies in paraffin sections.
Frozen sections are preferable for staining the deposits.
Further, A PCR study for immunoglobulin heavy chain gene rearrangement was consistent with the presence of a clonal B-cell population. Finally, electron microscopy was performed on the homogeneous pink tissue. A. Low-power view of a vessel wall. This pattern excludes amyloid. Subsequently, a PAS-D stain on a paraffin section showed a positive reaction.