We describe the presentation, treatment, clinical outcome, and targeted genome analysis of a metastatic salivary
acinic cell carcinoma (AciCC). A 71-year-old male presented with a 3 cm right tail of a parotid lesion, first detected as a nodule by the patient seven months earlier. He had a right total parotidectomy with cranial nerve VII resection, right facial nerve resection and grafting, resection of the right conchal cartilage, and right modified
radical neck dissection. The primary
tumor revealed AciCC with two distinct areas: a well-differentiated component with glandular architecture and a dedifferentiated component with infiltrative growth pattern associated with prominent stromal response,
necrosis, perineural invasion, and cellular pleomorphism.
Tumor staging was pT4 N0 MX. Immunohistochemistry staining showed pankeratin (+), CD56 (-), and a Ki67 proliferation index of 15%. Upon microscopic inspection, 49 local lymph nodes resected during parotidectomy were negative for
cancer cells. Targeted sequencing of the primary
tumor revealed deletions of CDKN2A and CDKN2B, a
nonsense mutation in ARID2, and single missense mutations of unknown significance in nine other genes. Despite postoperative localized
radiation treatment, follow-up whole body PET/CT scan showed lung, soft tissue, bone, and liver
metastases. The patient expired 9 months after resection of the primary
tumor.