Search

Background: Microvascular thrombosis is key to the pathogenesis of calciphylaxis. C5b-9-mediated microvascular injury reflective of complement pathway activation could be a key pathophysiologic event., Methods: We conducted a retrospective multicenter study of 24 patients who have had biopsy-supported calciphylaxis from the 2010-2022 data base from Emory where C5b-9 immunohistochemistry (IHC) had not been conducted and the 2019-2023 data base from Cornell where C5b-9 IHC was done as part of the routine calciphylaxis work up. IHC for C5b-9 on lesional biopsy specimens was assessed and correlated with routine light microscopic findings and clinical features., Results: Most of the patients in our study had uremic calciphylaxis associated with obesity, diabetes, dialysis, hypertension, hyperparathyroidism and elevated serum phosphorus. Most patients did not have defined procoagulant and/or hyperviscosity states. The vascular pathology was predominantly limited to the subcutaneous fat and ranged from a calcific intimal arteriopathy to microvascular thrombosis with endothelial injury with or without endothelial calcification. In most cases (ie, in excess of 80%), there was prominent deposition of C5b-9 within the vasculature including the microvasculature and arteries of the fat at least localized to injured vessels suggesting a causal association. In about 40% of cases, there was evidence of systemic complement pathway activation revealed by concurrent dermal microvascular C5b-9 deposition., Conclusions: Calciphylaxis is characterized by subcuticular vascular changes that reflect an interplay between complement triggered endothelial cell injury, resultant vascular thrombosis, and subsequent abluminal calcification. Complement inhibition therapy defines a potential intervention that should be explored., (Copyright © 2024 The Author(s). Published by Wolters Kluwer Health, Inc.)

Competing Interests: None disclosed.

Background: Pediatric melanoma presents with distinct clinical features compared to adult disease., Objective: Characterize risk factors and negative outcomes in pediatric melanoma., Methods: Multicenter retrospective study of patients under 20 years diagnosed with melanoma between January 1, 1995 and June 30, 2015 from 11 academic medical centers., Results: Melanoma was diagnosed in 317 patients, 73% of whom were diagnosed in adolescence (age ≥11). Spitzoid (31%) and superficial spreading (26%) subtypes were most common and 11% of cases arose from congenital nevi. Sentinel lymph node biopsy was performed in 68% of cases and positive in 46%. Fatality was observed in 7% of cases. Adolescent patients with melanoma were more likely to have family history of melanoma (P = .046) compared to controls., Limitations: Retrospective nature, cohort size, control selection, and potential referral bias., Conclusion: Pediatric melanoma has diverse clinical presentations. Better understanding of these cases and outcomes may facilitate improved risk stratification of pediatric melanoma., Competing Interests: Conflicts of interest SH reports honorarium from Elsevier and past consulting for Novan Pharmaceuticals., (Copyright © 2024. Published by Elsevier Inc.)