Zymbal's Gland and Preputial Gland Tumors

Tumors may arise from the Zymbal's holocrine glands within the subcutis at the base of the external ear. On gross examination, masses are circumscribed and lobu- lated (Fig. 2.76), and may become ulcerated. On micro­scopic examination, tumors consist of epithelial cells with abundant, vacuolated cytoplasm with squamous differ­entiation and keratinization (Fig. 2.77). Depending on their histologic pattern, they are classified as adenomas or adenocarcinomas. The malignant tumors are locally inva­sive, but are not metastatic. Similar tumors arise from the preputial glands of males (Figs. 2.78 and 2.79).