Treatment-Refractory Scleredema Diabeticorum Managed With Re-irradiation Using Volumetric Modulated Arc Therapy.

Scleredema diabeticorum is a rare connective tissue complication of diabetes, most typically observed in adults with longstanding type 2 diabetes. Patients develop reticular dermis thickening with a peau d'orange appearance at the upper back and neck that occasionally extends over the deltoids and lower back. While considered a benign disorder, it may signify more significant diabetes and can be functionally and cosmetically impairing with insidious onset, few to no effective treatments, and low spontaneous remission potential. Treatment options are limited; however, radiation therapy has shown clinical benefit in severe cases. Common treatment utilizes 20-24 Gy in 10-12 fractions with retreatment sometimes required for adequate symptom control. Here, we present a case of extensive, treatment-refractory diabetic scleredema status post six separate prior treatments with electron radiotherapy with clinical progression of disease, including involvement of anterior neck limiting jaw and neck range of motion. Volumetric modulated arc therapy (VMAT) was utilized to cover all areas of extensive disease and to treat deeper tissues, which we postulated may decrease skin and underlying tissue tightness and provide clinically meaningful improvements in range of motion. A 57-year-old female with longstanding type 1 diabetes and a six-year history of biopsy-confirmed scleredema presented with treatment-refractory disease in 2022 of the upper back, bilateral upper arms, and neck. Her disease distribution included 270 degrees around her neck, making electron therapy unviable. She had previously undergone multiple treatments, including six separate electron radiotherapy treatment courses to her back, shoulders, and posterior neck between 2016 and 2020 (ranging from 12 Gy in 6 fractions to 24 Gy in 12 fractions for each course), psoralen UV-A therapy, physiotherapy, methotrexate, and percussive therapy. To address the disease extending anteriorly around her neck and below her jaw, as well as the posterior involvement of her shoulders, back, and neck, a more extensive VMAT re-irradiation plan was developed. The plan successfully delivered 20 Gy in 10 fractions to areas of clinically evident disease. Toxicity was evaluated using the Common Terminology Criteria for Adverse Events (CTCAE) scoring system at the time of treatment and at the three-month follow-up. Functional improvement, patient satisfaction, skin texture, and induration were assessed during treatment and at her follow-up visit. Following VMAT re-irradiation, the patient denied scorable toxicity and noted the return of mobility in her neck and jaw. We concluded that VMAT-based re-irradiation is a safe and effective option for patients with treatment-refractory scleredema diabeticorum that is non-responsive or not amenable to electron therapy.