Chaotic transformation of parotid acinic cell carcinoma to metastatic dedifferentiated high-grade pathology- A rare case with clinical and emotional challenge

Introduction and importance: Acinic cell carcinoma (AciCC) is a rare entity in which high-grade transformation (HGT), formerly dedifferentiation, is uncommon. This case report presents a rare case of AciCC, with rapid transformation to metastatic high-grade dedifferentiated pathology after initial curative treatment. Case presentation: A 58-year-old woman presented in the medical oncology clinic with a progressive swelling on the right side of her face. Magnetic resonance imaging revealed a 5 x 5 cm lobulated parotid gland lesion, and fine needle aspiration biopsy was consistent with carcinoma. After informed consent, a Modified-Blair incision was given as a standard approach to the right preauricular area under general anaesthesia, and a right superficial parotidectomy with the removal of the tumor and selective lymph node dissection was performed. Histopa-thology of the resected mass was reported as parotid AciCC. She was given adjuvant radiation therapy. A repeat PET CT scan ten weeks after the completion of her adjuvant radiation treatment showed local disease recurrence as well as multiple pulmonary deposits. A repeat biopsy was reported as DOG-1 positive dedifferentiated (high-grade) acinic cell carcinoma, and she was offered platinum-based palliative systemic chemotherapy. Clinical discussion: Parotid acinic cell carcinomas with high-grade transformation are rare. This case highlights its critical diagnostic markers, curative and palliative management and long-term follow-up. Conclusion: The transformation of parotid AciCC to high-grade, dedifferentiated pathology is unusual and belligerent. Hence, these tumors need intense treatment with a multimodality approach. Close follow-ups with history and physical examination, along with periodic imaging, should be considered for these patients.