Isolated hilar mass mimicking cholangiocarcinoma as a rare metastatic manifestation of recurrent colorectal cancer: A case report.

backgroundColorectal cancer remains as one of the most common cancers that are diagnosed and remains as a significant contributor to morbidity and mortality. Despite advances in techniques, improving access to diagnostic modalities and increasing awareness, it often presents at a later stage and can recur despite treatment. Recurrence can be variable and can occur years after treatment. Liver is the most common location for metastasis to occur followed by lungs. However, atypical sites of metastasis can occur although unusual and colorectal cancer can spread to the spleen, hilum of the liver, adrenals, bone, skeletal muscles, skin, prostate, brain, parotid gland, thyroid gland and even the cardiac muscle. It is crucial to recognize the metachronous nature of the metastasis and to only present at a single site as within this lies the rarity of the case. The mass itself mimicked a cholangiocarcinoma or a Klatskin's tumor initially and only through pathology was the diagnosis established. We present an unusual case of recurrent colorectal cancer that occurred several years post treatment and presented as an isolated metastasis to the hilum of the liver leading to biliary obstruction without any other identifiable lesions including in the colon itself. CASE SUMMARY: A 68-year-old male with history of colon cancer presented with obstructive jaundice to the hospital. After evaluation with imaging studies was diagnosed with mass at the hilum of the liver that was leading to obstruction. With percutaneous biopsies obtained by interventional radiology, the diagnosis of metastatic adenocarcinoma originating from the colon was established. He was deemed not to be a surgical candidate and is currently pursuing chemotherapy.

conclusionA metastatic adenocarcinoma of the colon that presents as a hilar mass and mimics cholangiocarcinoma is very rare. The metachronous nature along with the isolated metastasis involving the hilum of the liver makes this case unique. Diagnosis can be challenging and needs a tissue specimen along with immunostaining to achieve an accurate diagnosis and provide appropriate treatment. Biliary decompression is performed either endoscopically or percutaneously and is part of the multidisciplinary approach involving medical and surgical oncology teams.