Enormous high-grade carcinoma arising from a pleomorphic adenoma in the parotid gland: A case report

Pleomorphic adenomas can undergo malignant transformation into carcinoma ex pleomorphic adenoma (CXPA). CXPA is challenging to diagnose due to its resemblance to benign tumors. Surgical excision is the primary treatment, with adjuvant radiotherapy recommended for high-risk cases. Despite the aggressive nature of CXPA, extensive surgery may not always be feasible, especially in cases with contraindications for neck dissection.

A 69-year-old female with a 20-year history of a slowly growing buccal mass presented with rapid enlargement over the last four months. Imaging and biopsy confirmed high-grade CXPA, and surgery was performed with careful dissection to preserve facial nerve function. The tumor measured 24 × 18 × 15 cm, and no perineural or lymphovascular invasion was detected. The patient received adjuvant radiotherapy and remained disease-free at 12 months, with preserved facial nerve function.

This case highlights the challenges of managing large CXPA tumors, particularly in preserving nerve function during surgery. The absence of perineural invasion in histological findings suggested a favorable prognosis, and postoperative radiotherapy significantly reduced the recurrence risk. While elective neck dissection is generally indicated in high-grade CXPA, it was contraindicated in this patient due to her medical condition.

CXPA, despite its aggressive nature, can often be managed without extensive resection or nerve sacrifice. In cases where neck dissection is not feasible, radiotherapy can be an effective treatment. Future research into the genetic basis and targeted therapies for CXPA is essential to enhance personalized treatment strategies and improve outcomes for patients with this complex malignancy.