Differential diagnosis between pleomorphic adenoma and carcinoma ex pleomorphic adenoma: focus on clinical and MR findings.

BACKGROUND

In parotid tumors, preoperative differential diagnosis between pleomorphic adenoma (PA) and carcinoma ex pleomorphic adenoma (CXPA) remains challenging.

OBJECTIVES

The present study aimed to evaluate the clinical characteristics of CXPA and PA and to identify factors associated with the differential diagnosis of these conditions.

MATERIAL AND

METHODS

We reviewed the medical records of 6 CXPA and 127 PA patients treated surgically at our institution between 2008 and 2024.

RESULT: Univariate analysis revealed significant differences in spontaneous pain (p = .044), facial nerve palsy (p = .045), and subjective enlargement (p < .01) between the CXPA and PA patients. Magnetic resonance imaging (MRI) revealed that the proportions of masses with ill-defined margins, localization in the deep lobe, and low apparent diffusion coefficient (ADC) were significantly higher in patients with CXPA than in those with PA (p < .01, p = .048, and p < .01, respectively). Multivariate analysis identified that spontaneous pain and masses with ill-defined margins were associated with CXPA (p = .047 and p = .013, respectively).

CONCLUSION

Spontaneous pain and masses with ill-defined margins could be suggestive of CXPA rather than PA. Low ADC levels indicate the possibility of CXPA.