Bone marrow predominant presentation of EGFR mutated NSCLC: Report of two cases

The Epidermal Growth Factor Receptor (EGFR) mutations are present in a minority of cases of non-small cell lung cancer (NSCLC), most commonly among never-smokers. In metastatic EGFR-positive NSCLC the most frequently involved sites are the bone and brain, a miliary metastatic subset also exists. However, cases with predominant bone marrow involvement have not been previously described. Here, we present two cases characterized by bone marrow predominance as an unusual initial imaging finding, with the diagnosis confirmed by bone marrow biopsy. Treatment was successful, comparable to usual EGFR-positive cases.