Pyoderma gangrenosum (PG) is a sterile neutrophilic disorder that rarely affects children. Clinical, epidemiological, and therapeutic data on pediatric PG is poor as there are many newly reported associated diseases and drugs. This paper aims to review all recent available data on pediatric PG. A systematic review of the literature was conducted using Embase, Medline, and Cochrane databases. A total of 132 articles were included in the review. The most commonly reported underlying diseases in pediatric PG are inflammatory bowel diseases followed by hematologic disorders, vasculitis, immune deficiencies and Pyogenic Arthritis, Pyoderma gangrenosum and Acne (PAPA) syndrome. More than half of the cases occur with no underlying disease. The most frequently reported clinical presentation is multiple disseminated ulcers. Treatment should be tailored according to the underlying etiology. It includes systemic steroids, corticosteroid sparing agents such as dapsone and cyclosporine, and TNF-alpha inhibitors such as adalimumab and infliximab. Response to treatment is high with cure rates reaching 90%. A high index of suspicion and a thorough workup are mandatory in the management of pediatric PG.

Introduction Keratoacanthomas (KA) are common cutaneous skin tumors originating from the hair follicles. Unlike squamous cell carcinoma, KA can regress spontaneously and have a benign evolution. Solitary KA is the most common form but familial multiple KA (Ferguson–Smith type), genetically predisposed KA (such as in xeroderma pigmentosum, or Muir–Torre syndrome), or sporadic multiple eruptive KA (Grzybowski type) have been described. Generalized eruptive KA of Grzybowski (GEKA) is a rare condition (around 40 reported cases). The pathophysiology is still unclear. Human papillomavirus (HPV) has been detected in sporadic KA but the presence of HPV39 has never been reported, to our knowledge, in GEKA. Case Report GEKA in an 80-year-old woman was successfully treated with acitretin (0.5 mg/kg/day) combined with surgical removal of the largest lesions. Treatment was well tolerated and led to decreased pruritus and tumor regression within 6 months. The presence of HPV39 was detected in a lesion by polymerase chain reaction and Sanger sequencing. No genetic alteration was found, in particular in the genes usually altered in squamous cell carcinoma (including NOTCH1 , NOTCH2 , CDKN2A , TP53 ). Conclusion We report a case of GEKA associated with the presence of HPV39 and the successful use of acitretin combined with surgical removal of the larger lesions.

Gastrointestinal toxicities of MEK inhibitors in melanoma patients are frequent. In clinical trials, the most common digestive adverse events were nausea, vomiting, and diarrhoea. However, severe toxicities such as colitis and gastrointestinal perforation, some with fatal outcomes, have been reported. These rare but severe adverse events are not well described. We performed a retrospective analysis of all patients with stage IV and unresectable stage III melanoma treated with a MEK inhibitors at Saint-Louis Hospital, Paris, between 1 August 2013 and 15 October 2018. Among 119 patients exposed to MEK inhibitors, 78 were treated with trametinib, 19 with cobimetinib, four with binimetinib, and 18 patients with two different MEK inhibitors at separate times. All grade digestive adverse events were observed in 39 (32.7%) patients. Grade 3 and 4 adverse events occurred in 6 (5%) patients: 2 (1.7%) developed perforations, 3 (2.5%) had colitis and 1 (0.8%) had grade 4 diarrhoea. These adverse events were all reversible following a permanent discontinuation of the MEK inhibitors, or a temporary interruption followed by resumption at a dose lower than conventional posology. There were no fatal outcomes; however one patient had a permanent ileostomy. The mechanism underlying these toxicities is not well known. Clinicians should be aware of such toxicities.