C. Cytomegalovirus infection
Examination of a punch biopsy specimen revealed epidermal ulceration with mixed dermal inflammation (Figure, B and C). There were large fibroblasts and endothelial cells with glassy cytoplasm and large intranuclear inclusions surrounded by a clear halo, giving the “owl’s eye” appearance (Figure, D). Inclusions were positive for cytomegalovirus (CMV) immunohistochemical stain. Quantitative PCR results demonstrated a CMV load of 172 000 copies/mL (5.24 log10 IU/mL) in the blood. A PCR swab from the ulcer base was positive for CMV. Based on these findings, a diagnosis of cutaneous ulceration secondary to CMV infection was made.
A common infectious complication after renal transplant, CMV increases the risk for allograft rejection.1 As with this patient, CMV-seronegative patients who receive renal transplants from seropositive donors are at highest risk of hospitalization from CMV disease.1 In patients who receive a transplant, CMV infection may lead to significant morbidity and mortality, most notably owing to CMV colitis. This patient had diarrhea; however, the diagnosis of CMV colitis was obscured by concurrent C difficile colitis.