Progression of Atypical Fibroxanthoma to Metastatic Pleomorphic Dermal Sarcoma in a Lung Transplant Recipient

Introduction: Atypical fibroxanthoma (AFX) and pleomorphic dermal sarcoma (PDS) are rare cutaneous malignancies often seen in elderly patients with photodamaged skin. Although solid organ transplant recipients (SOTRs) with AFX/PDS appear to have worse outcomes than the general population, the risk of progression from AFX to PDS in this group is not well studied.  We present the case of a lung transplant patient with AFX recurring as PDS. Case Presentation: A 68-year-old male lung transplant patient with an extensive history of skin cancer presented with a 9-millimeter erythematous papule on the right vertex scalp. Biopsy revealed AFX, and the tumor cleared with 1 stage of MMS. Seven months later, the patient developed a rapidly growing, hemorrhagic nodule at the site, which was diagnosed as PDS. Despite initial treatment with doxorubicin, pazopanib, and radiation to the lung, liver, and bone lesions, the patient’s disease progressed. The patient was started on pembrolizumab with prednisone to mitigate the risk of organ rejection but succumbed to pneumonia with septic shock and respiratory failure. Discussion: Transplant patients have an increased risk of poor outcomes related to PDS. ICIs may be considered in advanced cases in which other treatment options have been exhausted. In conclusion, SOTRs with AFX/PDS should be aggressively treated and monitored as their risk of unfavorable outcomes appears to be increased.