Role of FNAC in metastasizing malignant mixed tumor of the external auditory canal. A case report.

BACKGROUND: No previous report of metastasizing mixed tumor (pleomorphic adenoma) of the external auditory canal (EAC) has been described. CASE: A 12-year-old, Chinese girl with a history of mixed tumor of the EAC presented with a locally recurrent, aggressive tumor and metastases to the lung and bone five years later. The primary, locally recurrent and metastatic lung tumor showed epithelial and myoepithelial elements with duct formation, chondromyxoid stroma and mitotic activity in the cellular areas on histology. Fine needle aspiration cytology (FNAC) disclosed the presence of spindle cells blending into chondromyxoid fibrillar ground substance in the recurrent and metastatic lung tumors.
CONCLUSION: In primary mixed tumor of the EAC, FNAC plays a useful role in the diagnosis of recurrent and metastatic disease. Its ability to identify ominous features, such as increased mitoses in this case, may be limited by sampling. Since cytology and histology cannot reliably prognosticate, long-term follow up of mixed tumor of the EAC after complete excision is advocated.