Intraglomerular crescentic metastases of malignant melanoma

We describe here a patient with a metastatic malignant melanoma displaying crescentic lesions in the glomeruli. A 64-year-old woman was referred to our hospital because of a sudden increase of serum creatinine. Clinical diagnosis suggested rapidly progressive glomerulonephritis. Renal biopsy revealed diffuse crescentic lesions containing metastatic melanoma cells. These cells were also seen in the glomerular capillary lumina and tubules, and a few scattered tumor cells were also present in the interstitium. Glomerular metastasis is a very rare entity. To the best of our knowledge, this patient is the first to be described in the English language literature showing intraglomerular metastasis of malignant melanoma as demonstrated by needle biopsy and is only the second patient with intraglomerular metastasis presenting with acute renal failure.