Secondary Localized Cutaneous Amyloidosis is not Rare in Bowen's Disease and Bowenoid Papulosis.

Secondary localized cutaneous amyloidosis is a histopathological finding seen in the dermis, in various benign, premalignant, and malignant skin conditions, without clinical significance. The real incidence is not known. We aimed to investigate the phenomenon of secondary localized cutaneous amyloidosis in Bowen's disease and Bowenoid papulosis. We retrospectively evaluated the data of all cases with histopathological confirmation of Bowen's disease and Bowenoid papulosis between 2006 and 2017 in our Dermatovenereology and/or Pathology departments. Secondary localized cutaneous amyloidosis was observed in three patients with Bowen's disease (3/52; 5.8%) and in three patients with Bowenoid papulosis (3/18; 16.7%). Herein, we present the demographic, clinical and histopathological features of these six cases of secondary localized cutaneous amyloidosis in detail. Although the occurrence of secondary localized cutaneous amyloidosis in epithelial tumors is a well-known phenomenon, its incidence has not been previously reported in Bowen's disease and Bowenoid papulosis. Therefore, our results indicating a high incidence may be particularly important for Bowenoid papulosis, as its association with secondary localized cutaneous amyloidosis has only been shown in one case before. Moreover, in three of six cases, we histologically observed areas of regression with a marked prominence of amyloid deposition. Remarkably, two of these patients had a history of topical application of destructive agents which reveals a possible etiologic relationship between secondary localized cutaneous amyloidosis and cellular apoptosis/necrosis induced by these external agents.