Glomerular deposition of immune complexes as a first manifestation of malignant melanoma - a case report.

Introduction: Immune complex (IC) deposition in renal tissue is considered as a possible tumor marker. This raised the hypothesis that some tumor markers might be related to the patient prognosis, with emphasis in the possibility to detect them in tissue sample, not only in blood. We report a patient with membranous glomerulonephritis (MGN) and tumoral IC deposition that were detected previous to the diagnosis of melanoma.
Case Report: A 55-year-old male was admitted to our department with symptoms of renal disease; a kidney biopsy was performed and the diagnosis was phase II MGN. A few months later he returned to the hospital with ascites, dyspnea, anorexia, and macular erythematous skin lesions in the body. A new urinalysis showed proteinuria, hematuria, and leukocyturia; the chest X-ray showed a lung nodule; and a brain CT scan revealed a frontal nodular lesion, suggesting metastasis. The brain biopsy suggested the diagnosis of metastatic melanoma and a posterior kidney immunohistochemistry study with S-100 and HMB-45 antibodies showed glomerular and tubular positivity for these markers.
Conclusions: MGN and deposition of tumoral IC as a first manifestation of melanoma has not been previously reported. This case reinforces the importance of a clinical evolution focused on the diagnosis of a hidden cancer in patients with MGN. Oncologists should also be aware of the potential occurrence of glomerular lesion in their patients and that could be important during tumor therapy.