Pleomorphic adenoma of the parotid gland metastasizing to the scapular region: a case report.

BACKGROUND

Metastasizing pleomorphic adenoma (MPA) is a rare, incompletely understood enigmatic entity having the histologic appearance of benign pleomorphic adenoma and clinically malignant behavior. We report a case of MPA of the parotid gland that metastasized to the scapular region 6 years after the appearance of the primary lesion in the left parotid gland.

CASE

A 35-year-old woman presented with a palpable soft to firm mass of 3-cm diameter in the left scapular region that was slightly mobile over the underlying structures and a small swelling at the operated site of the parotid region. The patient had a prior history of surgical removal of recurrent pleomorphic adenoma of the left parotid salivary gland. Fine needle aspiration cytology (FNAC) smears of both sites demonstrated the 3 components (i.e., stromal, mesenchymal and epithelial) of benign pleomorphic adenoma with benign features. The diagnosis was MPA.

CONCLUSION

The appearance of a mass lesion or subcutaneous nodule with a prior history of pleomorphic adenoma should alert for the possibilities of metastatic carcinoma, metastatic carcinosarcoma and MPA. With well-established cytomorphology of pleomorphic adenoma, FNAC remains the investigation method of choice for metastatic workup of a case of locally recurrent pleomorphic adenoma.