A Retrospective Histologic and Histochemical Evaluation of Cutaneous Calciphylaxis
Mark Mochel, Ryan Arakaki, Guilin Wang, Daniela Kroshinsky, Mai Hoang. Massachusetts General Hospital, Boston, MA
Background: Calciphylaxis is a rare and life-threatening disease of vascular calcification and cutaneous necrosis. To confirm the diagnosis and exclude other diseases, skin biopsy is performed. However, skin biopsies are often non-diagnostic due to inadequate sampling or biopsy site. The objective of this study was to investigate the utility of various histologic features in rendering the diagnosis of calciphylaxis and to compare two histochemical methods, von Kossa (VK) and Alizarin red (AR), for detecting calcium deposits.
Design: The histologic and histochemical features of 56 skin biopsies from 27 consecutive patients with confirmed diagnoses of calciphylaxis were retrospectively analyzed and compared with those of 19 skin biopsies from 17 patients originally suspected to have calciphylaxis but determined to have other disease processes. Fisher's exact test was used to assess histopathologic features, with two-tailed p-values of <0.05 deemed significant.
Results: Vascular calcification and thrombosis were significantly associated with cutaneous calciphylaxis (Table 1). Peri-eccrine calcification, a subtle histologic finding, was highly specific to calciphylaxis and was the only form of calcium deposition present in four biopsies in the calciphylaxis group. Other epidermal, dermal, and subdermal changes were not significantly associated with calciphylaxis. Although VK and AR stains showed comparable detection of calcium in our study, the deposits seen on AR appeared larger and birefringent.
|Histologic features||Calciphylaxis (*)||Control||p-value||Sensitivity (*)||Specificity|
|Stippled calcification||36/56 (33/43)||0/19||< 0.0001||0.64 (0.77)||1.00|
|Chunky calcification||37/56 (25/43)||5/19||0.0034||0.66 (0.58)||0.74|
|Capillary calcification||28/56 (26/43)||0/19||< 0.0001||0.50 (0.60)||1.00|
|Any vessel size calcification||43/56 (32/43)||4/19||<0.0001||0.77 (0.74)||0.79|
|Peri-eccrine calcification||6/55 (6/43)||0/19||0.33||0.11 (0.16)||1.00|