Acinic cell carcinoma of parotid gland metastasis to left cavernous sinus: a case report and review of literature

Objective To investigate the clinical manifestations and pathological features of parotid gland papillary acinic cell carcinoma metastasis to left cavernous sinus. Methods The clinical manifestations, pathological features and differential diagnosis were studied in one case of parotid papillary acinic cell carcinoma metastasis to left cavernous sinus. Related literatures were also reviewed. Results The patient was a 50-year-old female who presented paroxysmal dizziness for 5 months and blurred vision in her left eye for 10 months. The MRI examination showed left parasellar space-occupying mass in the cavernous sinus. In operation, the tumor was located in the superior wall of left cavernous sinus, soft and red-grey in color, with abundant blood supply. The histomorphological examination revealed the tumor cells were arranged in solid, acinar or papillary pattern. The tumor cells were large, with eosinophilic cytoplasm, round or oval nuclei and small nucleoli. Immunohistochemical staining found that the tumor cells expressed cytokeratin (CK), epithelial membrane antigen (EMA), vimentin (Vim) and S-100 protein (S-100), and showed weak positive expression of glial fibrillary acidic protein (GFAP) and focal positive expression of P53 protein. Ki-67 labeling index was about 5%-10% . The tumor cells were negative for neuroendocrine markers and pituitary hormone protein markers. This case was difficult to differentiate from other primary intracalvarium tumors, including papillary meningioma, papillary tumor of choroid plexus, papillary ependymoma, papillary glioneuronal tumors as well as chordoma. According to the medical history and the comparison of histomorphology and immunophenotyping between parotid gland tumor cells and left cavernous sinus tumor cells, the final diagnosis was metastatic papillary parotid acinar cell carcinoma of the left cavernous sinus. The patient was followed for 21 months and no recurrence was seen. Conclusion It is very rare and to our knowlege it is the second case with metastasic papillary parotid acinar cell carcinoma in the cavernous sinus. Understanding the patient's history and differentiating from other primary intracalvarium tumors is one of the key steps to give right pathological diagnosis and clinical therapy. doi：10.3969/j.issn.1672-6731.2013.12.008