[482] 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.

Table 1: Histologic features of calciphylaxis versus non-calciphylaxis controls
Histologic featuresCalciphylaxis (*)Controlp-valueSensitivity (*)Specificity
Stippled calcification36/56 (33/43)0/19< 0.00010.64 (0.77)1.00
Chunky calcification37/56 (25/43)5/190.00340.66 (0.58)0.74
Capillary calcification28/56 (26/43)0/19< 0.00010.50 (0.60)1.00
Any vessel size calcification43/56 (32/43)4/19<0.00010.77 (0.74)0.79
Peri-eccrine calcification6/55 (6/43)0/190.330.11 (0.16)1.00
Vascular thrombosis37/567/190.0330.660.63
*evaluation with AR instead of VK

Conclusions: A stippled calcification quality and capillary calcification were highly specific to calciphylaxis. Although not statistically significant, peri-eccrine calcification was highly specific to calciphylaxis and may be useful in the evaluation of biopsies for calciphylaxis when classic features such as small vessel calcification are not present. As the VK and AR methods each stained occasional calcium deposits that the other method missed, performing both stains may increase calcium deposit detection.
Category: Dermatopathology

Monday, March 4, 2013 8:15 AM

Proffered Papers: Section F, Monday Morning


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