Morphea, Eosinophilic Fasciitis and Cancer: A Scoping Review

SIMPLE SUMMARY: Morphea and eosinophilic fasciitis (EF) are cutaneous autoimmune fibrosing diseases. We conducted a scoping review following PRISMA-ScR guidelines to ascertain the association between cancer and morphea/EF, focusing specifically on the paraneoplastic phenomenon, risk of subsequent cancer and development of morphea/EF as a consequence of cancer treatment. We identified that morphea patients, particularly those with generalized disease, might be at an increased risk of secondary malignancy, notably skin and pancreatic cancer. EF, on the other hand, occurred as a paraneoplastic disease in 10% of patients, primarily associated with hematologic malignancies. While reports of radiotherapy and chemotherapy-induced morphea are numerous, immunotherapy-induced morphea/EF cases are emerging. Interestingly, all immunotherapy-induced cases occurred with PD-1 inhibitors. ABSTRACT: Morphea is an autoimmune fibrotic skin disease. Eosinophilic fasciitis (EF) is considered to belong to the severe spectrum of morphea. We conducted a scoping review assessing the risk of secondary cancer among morphea/EF patients, paraneoplastic morphea/EF and morphea/EF developing secondary to cancer therapy. The search was conducted using MEDLINE, Embase, Cochrane databases for articles published from inception to September 2022 following the Preferred Reporting Items for Systematic reviews and Meta-Analyses for Scoping Reviews (PRISMA-ScR) guidelines with no language or date restrictions. Two hundred and one studies were included. Of these, 32 studies reported on secondary cancer in morphea/EF patients, 45 on paraneoplastic morphea/EF and 125 on cancer-treatment-induced morphea/EF. While the current evidence remains limited, data suggest an increased risk of secondary cutaneous and possibly pancreatic malignancy in morphea patients, particularly the generalized subtype. There were insufficient data for EF. On the other hand, paraneoplastic morphea was anecdotal, whereas several observational studies suggested that ~10% of EF cases may be paraneoplastic, primarily in the context of hematologic malignancies. Radiotherapy-induced morphea is rare, seen in ~0.2% of treated patients and is usually localized to the treatment site, except in patients with pre-existing autoimmunity. While chemotherapy-induced cases are reported, immunotherapy morphea/EF cases are emerging and are preferentially seen with PD-1 and not CTLA-4 inhibitors. This study is limited by the type of articles included (case reports, case series and observational studies), and hence, additional research on this important topic is needed.