Sarcomatoid carcinoma metastasis to bone marrow with unknown primary

Sarcomatoid carcinoma presenting as bone marrow metastasis with unknown primary is a rare entity. Usually patients present with widespread symptoms of extensive disease process. In the present case patient was evaluated for anemia and a subsequent bone marrow examination showed metastatic malignancy. All complimentary diagnostic tests were performed, Immunohistochemistry of bone marrow biopsy revealing presence of epithelia differentiation lineage markers with mesenchymal lineage markers also although routine biopsy showed only subtle mesenchymal component. The patient was referred to higher cancer centre and despite of elaborate laboratory work up including PET scan the primary origin of metastatic sarcomatoid carcinoma remained undetermined as patient unfortunately passed away within 10 days.