Histopathology of calciphylaxis: Cohort study with clinical correlations

Calciphylaxis is a rare, painful, and life-threatening condition with a high mortality rate. Although the etiology of calciphylaxis is not well understood, it has been proposed that calcium deposition within and around subcutaneous vessels restricts blood flow chronically, thereby predisposing the patient to acute pannicular and dermal thrombosis. Given increasing recognition of the role of hypercoagulability in calciphylaxis, this retrospective cohort study sought to evaluate the presence of thromboses and dermal angioplasia in calciphylaxis. Moreover, we aimed to validate previous observations about the histopathology of calciphylaxis compared with skin biopsies from patients with end-stage renal disease but without calciphylaxis. After a meticulous clinical chart review, we assessed the corresponding skin biopsies for the presence of vessel calcification, thromboses, and dermal angioplasia in skin biopsies from patients with calciphylaxis (n = 57) and compared with those from patients with end-stage renal disease but without calciphylaxis (n = 26). Histopathologic findings were correlated with clinical features such as chronic kidney disease, diabetes, or associated malignancy. Our results validated a prior observation that calciphylaxis was significantly more likely to show calcification of dermal vessels and diffuse dermal thrombi. This study reports the frequent finding of dermal angioplasia, a potential marker of chronic low-grade ischemia, as another frequent microscopic finding in calciphylaxis. Among cases of calciphylaxis, histopathologic changes in patients with chronic kidney disease were indistinguishable from those in patients without chronic kidney disease, thereby implying a final common pathogenic pathway in both uremic and nonuremic calciphylaxis. In future, larger, prospective studies may be useful in validating these findings.