Diffuse Primary Cutaneous Anaplastic Large Cell Lymphoma Treated by Rotational Total Skin Electron Beam Radiotherapy with Custom Shielding: Case Report

Introduction Primary cutaneous anaplastic large cell lymphoma (PCALCL) is a rare T-cell malignancy typically presenting as a solitary lesion treated with radiotherapy. Diffuse PCALCL is rare, and treatment paradigms of diffuse PCALCL are poorly defined. Case and Outcomes In this report, a 69-year-old male presented with progressive extensive truncal PCALCL resistant to brentuximab. The truncal lesions were treated with 36 Gy in 18 fractions by a novel approach using rotational electron beam radiation therapy with custom-made shielding. The treatment was well tolerated with expected dermatologic side effects managed supportively. All lesions achieved an initial complete response, and two sites within the treatment field recurred five months after treatment. Discussion This case adds to the limited literature on diffuse PCALCL and demonstrates an uncommon treatment approach to multifocal PCALCL using rotational electron beam radiation therapy with personalized shielding techniques. The treatment approach here was well tolerated by the patient with initial complete response at all sites. Maximal sparing was especially critical in this patient because of a history of previous head and neck irradiation. Shielded areas were validated by optically stimulated luminescent dosimeters showing dose reduction, confirming the utility of this method. Conclusion Rotational total skin electron beam with personalized shielding may be generalizable to cutaneous malignancies including PCALCL presenting with diffuse skin involvement. Further investigation of diffuse PCALCL is merited to optimize treatment strategies.