Risk factors for carcinoma ex pleomorphic adenoma in patients presenting with recurrence after resection of pleomorphic adenoma.

BACKGROUND

In patients presenting with recurrent pleomorphic adenoma (rPA), clinical evaluation can fail to recognize carcinoma ex PA (cxPA). We aim to identify the risk factors for cxPA.

METHODS

This is a single institution retrospective case-control study from 2000 to 2015. CxPA was diagnosed based on surgical pathology. Demographics, clinical, and social histories were collected.

RESULTS

A number of 13/106 (12.3%) patients were diagnosed with cxPA, of which only 4/13 (31%) had clinical features suspicious for malignancy. Compared to benign rPA, factors associated with cxPA included age >50 (odds ratio [OR] 6.67, 95% confidence interval [CI]: 1.71-25.98, P < .01), >10 pack-years of smoking history (OR 3.36, 95% CI: 1.01-11.14, P = .04), and the largest tumor being >2 cm on pathology (OR 4.42, 95% CI: 1.14-17.10, P = .03).

CONCLUSIONS

In patients presenting with rPA, risk factors for malignant transformation include age >50, significant smoking history, and tumors larger than 2 cm. Clinical signs of malignancy such as rapid growth or pain are not always present.