A Case Report of a Poorly Differentiated Neuroendocrine Carcinoma Diagnosed in the Bone Marrow

Neuroendocrine tumors are relatively rare tumors with an incidence of 5.25 per 100,000 per year in the United States [1]. They range from well differentiated slow growing tumors to highly aggressive poorly differentiated tumors [2]. The common primary sites of neuroendocrine carcinomas are lung and gastrointestinal tract. However, 3-5 % of these tumors are diagnosed as metastatic disease with unknown primary [3]. Bone marrow involvement by extra-pulmonary neuroendocrine malignancies has been rarely reported [3]. Here, we report a case of an aggressive high-grade metastatic neuroendocrine carcinoma to the bone marrow with unclear primary site.