Postherpetic Pseudolymphomatous Angiosarcoma Concealed Within Milia en Plaque: Expanding the Spectrum of Wolf Isotopic Response with a Literature Review.

The Wolf isotopic response (WIR) refers to the development of cutaneous lesions in areas of previously healed but unrelated skin disease. While most are observed in healed herpes zoster, WIR has been reported in various other contexts. Affected areas are believed to exhibit immune dysregulation, lymphatic dysfunction, and altered neuromediator activity, increasing susceptibility to inflammatory, neoplastic, and infectious conditions. This phenomenon aligns with the broader concept of the "immunocompromised district", which also encompasses the Koebner phenomenon and its reverse. Herein, we present the case of a 96-year-old woman who developed multiple cysts and comedones at the site of a resolved herpes zoster. Due to persistent and refractory inflammation, curettage was performed, and histopathological examination revealed angiosarcoma with a pseudolymphomatous reaction interspersed among the cysts. The coexistence of multiple types of WIR is rare but not unprecedented, highlighting the importance of recognizing the diverse pathologic conditions that can arise in such settings. In this review, we explore the historical evolution of terminology used to describe lesions in vulnerable skin areas and related phenomena. We also provide an updated overview of current pathogenic theories and present a comprehensive compilation of postherpetic reactions reported to date.