Paraneoplastic Focal Segmental Glomerulosclerosis Associated With Gastrointestinal Stromal Tumors With Cutaneous Metastasis: a Case Report

Abstract Background: Gastrointestinal stromal tumor (GIST) is one of most common mesenchymal neoplasms occurring in different areas of the gastrointestinal tract. GISTs with cutaneous metastasis is very rare and its rarity cutaneous GISTs have not been well characterized. Focal segmental glomerulosclerosis (FSGS) is also rare among paraneoplastic nephritic syndromes (PNS).Case presentation: In this case report, we described a 64-year-old patient with cutaneous metastasis GIST accompanied by nephrotic syndrome as PNS, in whom symptomatic treatment was ineffective, but clinical remission was achieved after surgery. Moreover, the patient has a missense mutation of NPHP4 . NPHP4 served as a negative regulator of the Hippo pathway. Hippo signaling pathway is involved in the development and progression of FSGS. NPHP4 is also indeed a driving force for proliferation in tumor cells. Therefore, the mutation of NPHP4 in this patient could explain the occurrence of GIST and FSGS and this was therefore not a random association.Conclusions: This is the first reported case of a GIST with cutaneous metastasis accompanied by nephrotic syndrome as PNS.