Dermatology: Practical and Conceptual Research Letter | Dermatol Pract Concept. 2024;14(1):e2024076 1 Successful Treatment of Pyoderma Gangrenosum with Composite Grafting of Acellular Dermal Matrix and Glycerolized Skin: A Preliminary Experience Linda Tognetti,1 Laura Calabrese,1 Elisa Pianigiani,2 Francesca Ierardi,2 Pietro Rubegni1 1 Dermatology Unit, Department of Medical, Surgical and Neurological Science, Dermatology Section, University of Siena, Siena, Italy 2 Skin Bank Unit, S. Maria alle Scotte Hospital, Siena, Italy Key words: pyoderma gangrenosum, skin allograft, acellular dermis, ulceration Citation: Tognetti L, Calabrese L, Pianigiani E, Ierardi F, Rubegni P. Successful Treatment of Pyoderma Gangrenosum With Composite Grafting of Acellular Dermal Matrix and Glycerolized Skin: A Preliminary Experience. Dermatol Pract Concept. 2024;14(1):e2024076. DOI: https://doi.org/10.5826/dpc.1401a76 Accepted: September 19, 2023; Published: January 2024 Copyright: ©2024 Tognetti et al. This is an open-access article distributed under the terms of the Creative Commons Attribution- NonCommercial License (BY-NC-4.0), https://creativecommons.org/licenses/by-nc/4.0/, which permits unrestricted noncommercial use, distribution, and reproduction in any medium, provided the original authors and source are credited. Funding: None. Competing Interests: None. Acknowledgements: drs Filomena Russo, Azzurra Sirchio, Roberta Castellano, Maria Chiara Vecchio Authorship: All authors have contributed significantly to this publication. Corresponding Author: Linda Tognetti, MD,PhD, Department of Medical, Surgical and Neurological Science - Dermatology Section, University of Siena, S. Maria alle Scotte Hospital, Viale Bracci 16, 53100 Siena, Italy. Tel: 0039-0577 585893. Fax: 0039 0577 585426 E-mail: linda.tognetti@dbm.unisi.it Introduction Pyoderma gangrenosum (PG) is a rare neutrophilic autoin- flammatory skin disorder presenting as a painful and rap- idly growing ulcer, with typical erythematous undermined edge, which can develop at injury sites due to pathergy phe- nomenon. PG is usually associated with immuno-mediate disorders such as inflammatory bowel diseases, rheumatoid arthritis and with neurological diseases. Given its unpre- dictable behavior, treatment must be tailored to the patient status and comorbidities. Briefly, the use of immunosuppres- sive drugs (steroids and cyclosporin) or immunomodulating (ie anti-TNFα inhibitors) proved to be effective in controlling inflammation. On the other hand, there is no consensus on which is the best topical treatment to stop the inflamma- tory loop and stimulate the ulcer healing [1]. Among them, a treatment protocol based on the grafting of autologous skin after adequate debridement through negative pressure wound therapy or hyperbaric oxygen therapy gave promising results in immunosuppressed patients [2,3]; we previously reported on positive outcome with glycerolized skin on a PG lesion  [4]. Recently, grafting of an acellular dermal matrix for a deep PG wound was described [5]. We here report our preliminary experience of two cases successfully treated with a composite grafting technique based on acellular dermal matrix and glycerolized skin pre- pared in the Skin Bank Unit of Siena Hospital [5,6]. Cases Presentation Case #1. A 52-year-old man with positive anamnesis for al- opecia universalis and an undetermined demyelinating dis- ease causing a right limb hemiplegia underwent orthopedic surgery for a hip titanium prosthesis implant, an ulcerative wound appeared after one week. Clinical appearance at presentation time 6 weeks after surgery showed a fibrinous 2 Research Letter | Dermatol Pract Concept. 2024;14(1):e2024076 lesion with undermined erythematous borders of 11x16 cm (Figure 1A). After the diagnostic confirmation by histo- pathology, treatment with Prednisone 32 mg/die and was Cyclosporine 250 mg/die started, then tapered until suspen- sion after 3 months and 6 months respectively. Atraumatic debridement was realized with topical collagenase and hy- drocolloids, then composite grafts was prepared: patches of acellular gamma-irradiated de-epidermized dermis (DED) were grafted into the deeper parts of the wound bed (Figure 1B), glycerol-preserved skin meshed 1:3 allografts (Figure 1C) were positioned to cover the whole surface; the grafts were stabilized with steri-strip (stiches were not per- formed to avoid pathergy phenomenon), double paraffin gauze layers were positioned (Figure 1D) and compressive dressing was performed. Epidermal allograft was replaced every 3 weeks for 2 times until intake (Figure 1E), then the graft was resized and double paraffin gauzes replaced every week. At month 3.5, dressing with rigenase-polyhexanide was applied every 3 days (Figure 1, F and G) until final clo- sure ( Figure 1H) after 5 months. The patient had no recur- rences at 8 months follow-up (Figure 1I). Case #2. A 90-year-old woman affected by diverticuli- tis developed a PG after trauma of the left thigh: she was under Prednisone 5mg/die, Methotrexate 15 mg weekly with folic acid for Horton arteritis. After the diagnostic confir- mation, prednisone was incremented to 25 mg/die. Once the wound bed was chemically debrided Figure 2A), composite allografts was realized as previously described (Figure 2B); after 1 month, the wound bed appeared reduced and filled with adequate granulation tissue (Figure 2C). The pa- tient died after 2 months for complications due to bowel perforation. Conclusions Skin allografts are well known to accelerate healing in hard-to-heal wounds [4,6]. Composite grafts are tailored ac- cording to wound specific features: the acellular DED, due to its poor immunogenicity, acts as an ideal scaffold guid- ing the host cells proliferation and preventing scarring while the overlying epidermal grafts ensure the optimal wound humidity and consent the re-epithelization. In particular, glycerolized skin allografts bring further advantages: being hypocellular, can be partially integrated into the PG wound bed, guiding re-epithelization; glycerol can significantly re- duce local pain, as reported by both patients. Figure 1. (A) Clinical appearance at presentation time of patient 1: large ulcerative lesion with fibrinous bed and undermined erythematous borders of 11x16cm; (B,C) Application of the acellular gamma-irradiated de-epidermized dermis patches into the deeper parts of the wound bed (B) and of the glyceropreserved epidermis meshed 1:3 allografts (C); (D) Fixation with steri-strip and double paraffin gauze layers. (E-L) Wound appearance 2 (E), 3 (F) and 4 (G) months after composite grafting. Final closure at month 5 (H) and follow-up at month 8 (I). Research Letter | Dermatol Pract Concept. 2024;14(1):e2024076 3 References 1. Maverakis E, Marzano AV, Le ST, et al. Pyoderma gangrenosum. Nat Rev Dis Primers. 2020;6(1):81. DOI: 10.1038/s41572-020 -0213-x. PMID: 33033263. 2. Pichler M, Thuile T, Gatscher B, et al. Systematic review of sur- gical treatment of pyoderma gangrenosum with negative pres- sure wound therapy or skin grafting. J Eur Acad Dermatol Venereol. 2017;31(2):e61-e67. DOI: 10.1111/jdv.13727. PMID: 27225541. 3. Araújo FM, Kondo RN, Minelli L. Pyoderma gangrenosum: skin grafting and hyperbaric oxygen as adjuvants in the treatment of a deep and extensive ulcer. An Bras Dermatol. 2013;88(6 Suppl 1): 176-178. DOI: 10.1590/abd1806-4841.20132680. PMID: 24346912. PMCID: PMC3875967. 4. Tognetti L, DePiano E, Perotti R, et al. Clinical applications of skin Bank bioproducts. Technology in Practical Dermatology. Non- Invasive Imaging, Lasers and Ulcer Management. 2020:443-449. 5. Nita M, Pliszczyński J, Kowalewski C, et al. New Treatment of Wound Healing With Allogenic Acellular Human Skin  Graft: Preclinical Assessment and In  Vitro Study. Transplant Proc. 2020;52(7):2204-2207. DOI: 10.1016/j.transproceed.2020.02. 115. PMID: 32340748. 6. Tognetti L, Pianigiani E, Ierardi F, et al. The use of human acel- lular dermal matrices in advanced wound healing and surgical procedures: State of the art. Dermatol Ther. 2021;34(4):e14987. DOI: 10.1111/dth.14987. PMID: 33993627. Figure 2. (A) Wound appearance after chemical debridement; (B) Glycero-preserved epidermis meshed 1:3 allografts positioned to cover the whole surface; (C) Lesion after 1 month: the wound bed appeared reduced and filled with adequate granulation tissue.