[Myoepithelial carcinoma ex-pleomorphic adenoma of the parotid gland]

[Myoepithelial carcinoma of the lacrimal gland]

INTRODUCTION

Myoepithelial carcinomas are unusual tumors most often located in salivary glands. It is very rarely located in lacrimal glands; only 5 cases have been reported. We report a sixth case.

OBSERVATION

An 88-year-old male patient presented with diplopia, painless right sided exophthalmia, as well as eyeball deviation due to a tumor located at upper external quadrant of the orbit. A biopsy initially suggested a sarcoma. The pathological analysis of the biopsy allowed diagnosing a myoepithelial carcinoma of the lacrimal gland. Despite the monoblock resection of the tumor, a recurrence was observed 3 months after removal. The patient died 8 months after the initial surgery.

DISCUSSION

This case illustrates the clinical and pathological characteristics of a myoepithelial carcinoma. This tumor has a high grade of malignancy, and is very rarely described in lacrimal glands. The morphological diagnosis of this tumor is difficult with a problematic differential diagnosis with fusiform cells sarcomas (leiomyosarcoma, undifferentiated sarcoma), and epithelial-myoepithelial carcinoma.

Low-grade malignant myoepithelioma arising in a pleomorphic adenoma: a rare case

Malignant myoepithelioma is a very rare salivary gland tumor that can arise de novo or within a pre-existing pleomorphic adenoma. We report a case of malignant myoepithelioma most probably arising in a pre-existing pleomorphic adenoma of the left parotid gland. The patient was a 60-year-old man who presented with a multinodular mass lesion over left side of the face and neck. He had undergone removal of a pleomorphic adenoma of the left parotid gland twice (8 and 22 years ago). Histological examination showed locally concentrated highly invasive myoepithelial cells with bland-looking morphology and no evidence of mitosis or necrosis. Immunohistochemistry confirmed the myoepithelial differentiation (S- 100+, SMA+) and a low Ki-67 labeling index (<5%).