Bone Marrow Necrosis Caused by Metastatic Colon Cancer A37-year-oldmanpresentedtoourcliniccomplainingofbloody stoolpassageoverthepreviousweek.Colonoscopyfoundamassover

the sigmoid colon, and a biopsy disclosed adenocarcinoma. A hemogramrevealedanemiaandthrombocytopenia.Lowanteriorresection and transverse loop colostomy were performed after aggressive platelet transfusion. Blood clots passed from the colostomy persistently after the surgery. Laboratory data revealed elevated concentration of D-dimer (6562 ng/mL), progressive anemia, and profound thrombocytopenia (19,000/L) 6 days after the operation. The patient complained of regional soreness and pain over the long bone area. A whole-body bone scan revealed inconclusive bony metastasis. The histologicalfindingsofabonemarrowbiopsyrevealedextensivemarrow necrosis with few surviving cancer cells (Fig 1A). The cancer cells stained positively for p53 (Fig 1B, arrows). The patient was treated withcetuximabplusoxaliplatin,fluorouracil,andleucovorin.During the first month after the start of treatment, the passage of blood clots decreased gradually and the platelet count returned to normal. Despitetreatment,thepatientdiedofdiseaseprogression3monthslater. BonemarrownecrosisisasyndromefirstreportedbyWadeand Stevenson 1 in1941.Thetypicalfindingsarenecrosisofmyeloidtissue and medullary stroma leaving an amorphous eosinophilic background, ill-defined necrotic cells, and preserved cortical bone. 2 The pathophysiology of bone marrow necrosis is still unclear. Failure of the microcirculation accompanied by hypoxemia causes damage to thecells.Thetoxicityandthereleaseoftoxins,cytokines,orvasoactive