Signet ring cell neuroendocrine tumor liver with mesenteric metastasis: Description of a rare phenomenon, with literature review

Primary hepatic signet ring cell neuroendocrine tumor (NET) is extremely rare, and may show both neuroendocrine and glandular differentiation. Unlike the usual signet ring cells of adenocarcinoma, these cells are characterized by mucin negative, cytokeratin and chromogranin positive intracytoplasmic vacuoles resembling signet ring cells. These tumors are usually well demarcated surgically resectable lesions. To the best of our knowledge, we report the fifth case of primary hepatic signet ring cell NET, with the present case bearing multiple hepatic space occupying lesions and mesenteric metastasis. Due to very few isolated reports, prognosis of NET with signet ring cell morphology is largely unknown. Documentation of this case with review of related literature may enrich the existing knowledge regarding the outcome and management of this rare tumor.