We present a case of a 66-year-old man with esophageal carcinoma. 18Fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) for evaluating distant metastasis and staging revealed 18F-FDG uptake in the third lumbar vertebra and other vertebrae. Magnetic resonance imaging could not differentiate bone metastases from benign bone lesions. We considered the possibility of bone marrow reconversion. 111Indium chloride (111In-Cl3) scintigraphy with single-photon emission computed tomography/computed tomography (SPECT/CT) revealed erythroid bone marrow components in the bone lesions. The diagnosis of bone marrow reconversion was pathologically confirmed by a bone biopsy of the third lumbar vertebra. The patient underwent esophagectomy and has remained disease-free in the 2 years since. To the best of our knowledge, this is the first report to describe the usefulness of 111In-Cl3 with SPECT/CT for the diagnosis of bone marrow reconversion.