Abstract: This paper reports the imaging and clinical features of a patient with an atypical parathyroid adenoma characterized by recurrent fractures, high parathyroid hormone level, negative ⁹⁹Tc^m-methoxyisobutylisonitrile (MIBI) SPECT imaging at initial diagnosis and positive ⁹⁹Tc^m-MIBI SPECT/CT tracking imaging at follow-up. By reviewing and analyzing relevant literature, this paper aims to explore the diagnostic approach when both CT and ultrasound localization diagnostic results are negative, and even when the ⁹⁹Tc^m-MIBI SPECT/CT imaging are still negative, in order to improve the understanding and early diagnosis of atypical parathyroid adenoma and avoid clinical missed diagnosis.