Advanced Colorectal Cancer Manifested with Bone Marrow Metastasis and Presented Clinically as Thrombotic Thrombocytopenic Purpura (TTP)

Bone marrow metastasis of colorectal cancer commonly occurs subsequent to invasion of the liver and lungs. Metastasis directly to the bone marrow without liver or lung involvement is rarely reported in literature; thus, little is known about its clinical manifestations. We present a rare case of advanced colon cancer manifested with bone marrow metastasis and clinical presentation of thrombotic thrombocytopenic purpura (TTP). Thrombotic thrombocytopenic purpura, although atypical among colorectal cancer, should not be overlooked as a possible indicator of advanced disease with bone marrow metastasis.