Etiopathogenesis of the pathologic lesions forms the basis for formulation of appropriate intervention and further prevention. There is still a vast unknown field that has to be explored to know the causative reason behind certain benign & malignant lesions. Idiopathic bone defects are nonodontogenic pseudocystic cavities that are seen in the long bones & jaw bones. Radiographic interpretation is at times inadequate in diagnosis of odontogenic & nonodontogenic radiolucent lesions involving jaw bones. Histopathology has different criteria to segregate this lesion. In this paper, we discuss a case of type B histopathological variant of idiopathic bone defect that may suggest an alternative pathogenesis from type A variant.