Membranous nephropathy and hepatitis secondary to syphilis: a case report and literature review.

Syphilis is a re-emerging infectious disease with diverse clinical manifestations; however, renal and hepatic involvement remains rare and under-recognized. Here, we describe the case of a 58-year-old man who presented with nephrotic syndrome. He had noted bilateral leg edema 1 month prior to presentation. Renal function was preserved; however, serum alkaline phosphatase (ALP) and γ-glutamyl transpeptidase (γ-GT) levels were elevated. Renal biopsy confirmed a diagnosis of membranous nephropathy (MN). In addition to positive results for both the Treponema pallidum antibody and rapid plasma reagin tests, a positive immunohistochemistry result for neuron-derived neurotrophic factor (NDNF), an antigen specific to syphilis-associated MN, suggested MN secondary to syphilis. Syphilitic hepatitis was also considered the likely cause of liver damage. Following antisyphilitic therapy, the nephrotic syndrome entered complete remission, and ALP and γ-GT levels normalized. This case serves as a reminder that renal and hepatic impairments can occur in patients with syphilis. To date, only a few cases of concurrent MN and hepatitis as complications of syphilis have been reported. Among these cases, this is the first reported case of NDNF-positive MN. We present this case along with a review of previously reported cases.