The gingival biopsy in the diagnosis of thrombotic thrombocytopenic purpura

Gingival biopsy specimens from five patients with a clinical diagnosis of thrombotic thrombocytopenic purpura (TTP) were reviewed. All biopsy specimens demonstrated the characteristic histologic lesion associated with TTP. Review of the literature showed an average diagnostic yield of 37% ( 30 81) for this procedure. The increase in diagnostic correlation in this study may be explained in part by the marked degree of disease expression in the patients who underwent gingival biopsy. Three of the five patients who underwent gingival biopsies ultimately died of their disease. In addition, a persistent search through multiple serial sections for the characteristic lesion, beyond the usual three levels, was performed. Despite the disparity in diagnostic yield, we consider the gingival biopsy to be a safe diagnostic correlate of TTP because of easy access, rich vascularity, and low surgical morbidity. Furthermore, we recommend biopsy, as Goodman and colleagues have, only in areas of the gingiva that appear clinically normal and free of inflammation in order to reduce misinterpretation as a consequence of false-positive intraluminal fibrin thrombi that may occur with inflammation.