Fluorescence in situ hybridization (FISH) as an aid for the diagnosis of graft-versus-host disease in two multivisceral organ transplant patients.

We herein describe 2 cases of adult multivisceral transplant patients who developed graft-versus-host disease manifesting predominantly as lichenoid skin papules and plaques. The diagnosis was supported by histopathology but ultimately corroborated by the utilization of the fluorescence in situ hybridization (FISH) technique using X and Y chromosome probes on unstained biopsy slides. In both cases, FISH revealed a high percentage of donor-derived cells as part of the inflammatory infiltrate in the skin biopsy. This report adds to the previous publications showing the utility of FISH in corroborating the diagnosis of graft-versus-host disease in transplant patients with unmatched sex donor.