Diffuse idiopathic skeletal hyperostosis (DISH) is a non-inflammatory condition characterized by progressive ossification of the entheses, often asymptomatic and underdiagnosed. We report the case of a 56-year-old female patient followed for a left mandibular carcinoma, with no spinal pain. Whole-body bone scintigraphy, complemented by SPECT/CT of the thoracolumbar spine, revealed a heterogeneous right lateral paravertebral uptake from D5 to D12, corresponding to multilevel anterolateral hyperostosis with cortical thickening and enveloping ligamentous ossification, characteristic of DISH. Additional areas of increased uptake were identified at the mandibular and costal levels, consistent with suspicious neoplastic lesions. This case illustrates the major value of SPECT/CT in confirming the diagnosis of DISH, even when asymptomatic, and in distinguishing degenerative or tumoral abnormalities. Functional imaging coupled with morphological imaging enables precise characterization of enthesopathic abnormalities, facilitates clinical monitoring, and optimizes patient management, thereby reducing the risk of misdiagnosis.