Paraneoplastic focal segmental glomerulosclerosis associated with gastrointestinal stromal tumor with cutaneous metastasis: A case report

BACKGROUND: Gastrointestinal stromal tumor (GIST) with cutaneous metastasis is very rare. As a result, cutaneous GISTs have not been well characterized. Focal segmental glomerulosclerosis (FSGS) is also a rare symptom among paraneoplastic nephritic syndromes (PNS). CASE SUMMARY: In this case report, we describe a patient with cutaneous metastatic GIST accompanied by nephrotic syndrome occurring as a malignancy-associated PNS, for whom symptomatic treatment was ineffective, but clinical remission was achieved after surgery. Moreover, the patient has a missense mutation in NPHP4, which can explain the occurrences of GIST and FSGS in this patient and indicates that the association is not random. CONCLUSION: This is the first reported case of a GIST with cutaneous metastasis accompanied by nephrotic syndrome manifesting as a PNS.