Osteomesopyknosis—a benign axial hyperostosis that can mimic metastatic disease

We report two cases of an axial osteosclerosis with histopathologic findings of osteomesopyknosis in siblings. Osteomesopyknosis is a benign hereditary osteosclerosis that can show a radiologic pattern similar to blastic metastatic disease. The aim of this article is to inform radiologists about the existence of this benign condition and its various radiologic manifestations. Therefore, we discuss the principal differential diagnosis and point out the key imaging findings of osteomesopyknosis in order to avoid overdiagnosis in future cases.