mucoepidermoid tumor of skin

MUCOEPIDERMOID CARCINOMA OF THE PAROTID GLAND

PRESENTING AS A RETROAURICULAR CYST

There was no history of a salivary gland tumor prior to the removal of this subcutaneous cyst, and there was no clinically apparent connection. The cyst was easily removed. Because of the strong resemblance of this structure to a low grade mucoepidermoid carcinoma of salivary gland origin, additional tissue was removed. This contained more of this type lesion. A parotid lobectomy was then performed, and this revealed an intermediate grade mucoepidermoid carcinoma. Dr. Ralph Rohr tells me that he has seen several mucoepidermoid carcinomas of the parotid gland that presented as a retroauricular mass. Mucoepidermoid carcinomas of salivary gland origin may be deceptively benign appearing in part or throughout.

Mucus production can be seen in a variety of skin lesions including Paget's disease, extramammary Paget's disease, mucinous syringometaplasia, and in adnexal tumors, particularly clear cell hidradenomas (variant of acrospiroma).

Low power view of one area lining the lumen. Since most of this lesion is cystic and there is orderly production of mucin, this component would be classified as a low grade mucoepidermoid carcinoma.

A high power view of above.

Another high power view.

High power view of one of the few nests of tumor in the fibrous wall of the cyst.

The parotid gland specimen is seen in the images below. The tumor within the parotid gland is mostly solid, mostly squamous, and it has infiltrating characteristics. This places it in a higher grade than one might classify the subcutaneous component. Mitotic activity is very minimal; there is no necrosis, and neurotropism was not demonstrated. Therefore it could be designated as an intermediate grade tumor. Slides of the salivary gland specimen were kindly provided by Ralph Rohr and Lester Layfield of the University of Utah Surgical Pathology Department.

Scan power view of the parotid gland (blue tissue across lower right part of picture) and tumor within it. The tumor is mostly solid though there are a few small cystic areas. Most of the tumor has squamous or intermediate cell features.

High power view of the squamous component. A few intercellular bridges are barely visible.

High power view of a small cystic area. Many of the cells lining the intracystic papillary structure have mucinous, lightly vacuolated cytoplasm. The mucinous component was minor in the salivary gland part of the tumor.

A focus of sebcaceous differentiation. This is sometimes found in several different types of salivary gland tumors and is of interest but of no known prognostic significance.

Click on your browser's 'Back' button to go to the previous page.

	Low power view of one area lining the lumen. Since most of this lesion is cystic and there is orderly production of mucin, this component would be classified as a low grade mucoepidermoid carcinoma.
	A high power view of above.
	Another high power view.
	High power view of one of the few nests of tumor in the fibrous wall of the cyst.

	Scan power view of the parotid gland (blue tissue across lower right part of picture) and tumor within it. The tumor is mostly solid though there are a few small cystic areas. Most of the tumor has squamous or intermediate cell features.
	High power view of the squamous component. A few intercellular bridges are barely visible.
	High power view of a small cystic area. Many of the cells lining the intracystic papillary structure have mucinous, lightly vacuolated cytoplasm. The mucinous component was minor in the salivary gland part of the tumor.
	A focus of sebcaceous differentiation. This is sometimes found in several different types of salivary gland tumors and is of interest but of no known prognostic significance.