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Reported reaction rates with gadolinium-based contrast agents (GBCA) ranged from 0.07% to 2.4%, the rate of hypersensitivity reaction (HS) is around 0.1% 1 and immediate and delayed HS have been reported. [1][2][3][4] The diagnosis of HS to GBCA is challenging, based on clinical history and skin tests. Although little data are available on the performances of the GBCA skin tests, its negative predictive value appears to be of interest. 5 Some classes of GBCA had been commercialized, grouped according their chemical structures and properties: macrocyclic or linear and ionic or non-ionic GBCA; some linear GBCA called protein-binding agents had briefly bound serum albumin or other proteins. A recent systematic review and meta-analysis reported that a higher rate of immediate HS was associated with ionicity, protein binding, and macrocyclic structure of GBCA. 6 From 2004 to 2009, the FDA received reports on 40 gadoliniumbased contrast agent U.S. deaths unrelated to nephrogenic systemic fibrosis, with an incidence per million doses of 0.15, 0.19, 0.97, 2.7, and 0.7 for gadodiamide, gadoversetamide, gadopentetate dimeglumine, gadobenate dimeglumine, and gadoteridol, respectively. 2The aim of this retrospective study was to evaluate the performances of skin tests and an intravenous provocation test (IPT) with low-dose GBCA in patients with suspected HS to GBCA.We report an observational retrospective study, in accordance with local ethics committee. We enrolled all patients with a history of HS to GBCA who underwent skin tests and IPT with low-dose GBCA between January 2013 and December 2015. Skin tests were performed following the EAACI-ENDA recommendations. 7 Briefly, skin prick tests (PTs) involved undiluted GBCA commercial solutions, and, when negative, were followed by intradermal tests (IDTs) successively with 100-fold and/or 10-fold solution diluted in 0.9% sterile saline. Readings were performed at 20 minutes, and at Day 2 in case of delayed HS. After signed informed consent from the patient, a single-blind placebo-controlled IPT, during 8-hours hospital stay with 1 mL of the GBCA solution (corresponding to one tenth of the usually injected GBCA for magnetic resonance imaging [MRI]), was proposed with gadoteric acid, if the skin test result remained negative, and with another GBCA if the patient requested a particular GBCA. The IPT result was considered positive for immediate HS if oxygen saturation decreased below 90% and/or a skin eruption (urticaria, angioedema or maculopapular rash) occurred up to 2 hours after the challenge and a skin eruption occurred between 2 hours and up to 7 days after the challenge for delayed HS.Fourteen patients had skin tests and IPT with GBCA; 12 of them had immediate HS, one a delayed HS, and one could not be classified due to missing information. The severity of the immediate HS was grade I and grade II according to Ring and Messmer severity classification, for respectively four and eight out of 12 patients and one delayed HS occurred with exanthema and dyspnoea more than 6 h...

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Cutaneous squamous cell carcinoma (cSSC) is one of the most common skin cancers and can lead to patient death. Early detection of node metastasis is a major goal for dermatologists and oncologists. The procedure sentinel lymph node biopsy has been proposed to improve early detection of node metastasis. The aim of this study was to evaluate the efficacy and impact of this technique on the prognosis of cSSC. A total of 37 patients (Saint Louis Hospital, Paris, France) who had undergone sentinel lymph node biopsy and 290 cases from the literature were analysed. The mean rate of positive sentinel lymph node biopsy was 0.14 [95% CI 0.09-0.22]. However, relapse-free survival and overall survival were not affected by sentinel lymph node status (log-rank test; p = 0.08 and p = 0.31, respectively), suggesting that this procedure is not mandatory in the management of cSSC.