Cutaneous complications in hematopoietic cell transplant recipients: impact of biopsy on patient management.

The utility of cutaneous biopsies in directing the management of post-hematopoietic cell transplantation (HCT) eruptions remains uncertain. We retrospectively analyzed 439 consecutive HCT procedures for malignant hematologic disorders performed at our institution between January 2005 and December 2012; 192 patients underwent 430 cutaneous biopsies. The clinical and dermatopathologic diagnosis differed in 240 cases (56%). Biopsy results led to a change in therapy in 69 (16%) episodes. Seventeen of 69 management changes occurred in response to a clinical diagnosis of graft-versus-host disease and resulted in augmentation of systemic immunosuppression. The management was modified with similar frequencies with respect to concordance or discordance between the clinical and histopathologic diagnosis (P = .51). We used classification and regression tree (CART) analysis, a decision-modeling technique, to predict the biopsy yield as expressed by impact on clinical management in the allogeneic and autologous setting. The models were cross-validated and then tested against a validation subset, and they maintained a high negative predictive value and high specificity. Although skin biopsies may not be mandatory for either diagnostic or therapeutic reasons, in carefully chosen circumstances, this procedure can yield extremely important data. We believe a prospective study should be undertaken to evaluate current practice data and to validate our decision tree models.