Tubulointerstitial and intraglomerular metastasis with subsequent development of tumor lysis syndrome in a patient with advanced metastatic melanoma

Background: While up to 50% of patients with malignant melanoma will have micrometastases to their kidneys, clinically apparent kidney metastasis is rare. Furthermore, intraglomerular metastases have been documented in only 3% of cases of disseminated malignancies. We present an unusual case of acute kidney injury secondary to tubular injury due to tubular or vascular obstruction by melanoma and intraglomerular metastasis followed by the development of tumor lysis syndrome after treatment. Case report: A 45-year-old male with previously normal kidney function and an established diagnosis of extensive metastatic melanoma presented to the emergency department for abdominal discomfort. Despite treatment with pembrolizumab and azacitidine, he had progression of disease. Subsequently, he developed progressive, unexplainable decline in kidney function and urinalysis that was notable for white blood cells, microscopic hematuria, and microalbuminuria with hyaline casts. The kidney biopsy revealed marked infiltration of melanoma cells characterized as multifocal tubulointerstitial and intraglomerular metastases, mild tubular injury, and no evidence of nephritis. Chemotherapy with paclitaxel was initiated to reverse-presumed cancer-induced kidney injury, but within 24 h, tumor lysis syndrome developed. Despite aggressive supportive measures including hemodialysis, his clinical course was irreversible and transitioned to comfort measures. Conclusion: Acute kidney injury secondary to metastatic tubulointerstitial and intraglomerular melanoma is a rare clinical entity that should be considered as the cause of acute kidney injury in a patient with extensive disease. Patients with extensive disease should also be cautiously monitored for the development of tumor lysis syndrome during treatment.