Metastatic Melanoma of Unknown Primary with Plasmacytoid Morphology Presenting as Acute Liver Failure

Abstract Introduction/Objective Viral hepatitis, drug toxicity, and autoimmune disorders are common etiologies of acute liver failure (ALF). Very rarely, a cause like metastatic melanoma may present as a primary driver of ALF. Malignant melanoma is histologically diverse and plasmacytoid melanoma is an unusual variant that may present as a solitary tumor or metastatic disease. Methods/Case Report A 48-year-old female presented with 2 weeks of right upper quadrant pain, nausea, coffee ground emesis and bleeding per rectum. She had no history of liver disease or alcohol use. On presentation, AST was 83 U/L, ALT was 29U/L, ALP was 159U/L and total bilirubin was 12.7g/dl. Viral hepatitis panel, HIV and chronic liver disease workup was negative. Esophagogastroduodenoscopy and colonoscopy showed no sources of bleeding. She was diagnosed with decompensated cirrhosis, ALF, and acute kidney injury from hepatorenal syndrome. Cirrhosis and multifocal indeterminate T1 hyper/T2 hypo intense lesions (dysplastic or regenerative nodules) were seen on MRI. Liver biopsy revealed metastatic melanoma. Almost entire liver parenchyma on biopsy was replaced by a population of neoplastic cells with plasmacytoid features. Immunostaining was positive for MART-1, HMB45 and SOX-10. Staining for Pan Cytokeratin and CK-7 highlighted the bile ducts and negative staining was seen for CK20, CD3, CD20, PAX-8, GATA-3, CDX-2 and P63. No primary lesion was found. It was deemed unlikely that she would benefit from therapy before complications occur. She passed away in 16 days. Results (if a Case Study enter NA) NA Conclusion In most cases of ALF associated with malignant melanoma, the liver may have a seemingly normal appearance on imaging studies due to the distinctive histology of leukemoid tumor infiltration within the liver sinusoids, resulting in sinusoidal obstruction and subsequent hepatocellular dysfunction. The rapidity of liver failure in these cases is related to the replacement of liver parenchyma by malignant cells. The plasmacytoid morphology is seen in a variety of malignancies and to avoid a potential misdiagnosis of an aggressive malignant melanoma, it is imperative to perform a thorough histopathological evaluation aided with immunohistochemistry. It is important to keep in mind that the potential involvement of malignant tumor cell infiltration may cause ALF and early histological assessment with a liver biopsy may be of paramount significance and may possibly change the course of the disease.