A 53-year-old male present with a chief complaint of a 5 month history of rapid growth of a right parotid gland mass that had been stable for 20 years. Magnetic resonance imaging revealed a 6 cm lesion of the right parotid gland with pathologic lymph nodes in the ipsilateral cervical region.
A total parotidectomy with a functional neck dissection was performed. Macroscopically, two distinct tumors were identified, one located in the superficial lobe with a diameter of 5.5 cm and the other located in the deep lobe with a diameter of 3.5 cm. On cut surface both lesions were firm, yellow in color with a nodular-infiltrative growth pattern. In the deep lobe, the mass had some fleshy, myxoid areas.
Microscopically the tumor in the superficial lobe exhibited a tumor composed of large, round, polyhedral cells arranged in small clusters, with isolated individual cells, and occasionally, solid sheets. On hematoxylin and eosin (H&E) slides, cells had abundant, finely granular, eosinophilic cytoplasm. Many of the oncocytic cells had pleomorphic, medium or large nuclei with an eosinophilic irregular, macronucleoli (Figs. , ). Necrosis and extensive lymphovascular tumoral thrombi were noted, but no comedonecrosis, tubular, cribriform or papillary areas were seen (Fig. ). Focally, oncocytic changes were noted in residual normal salivary gland parenchyma. In the deep lobe, in addition to the neoplastic oncocytes, there was close association of various epithelial cell types some forming ductal structures and myxoid mesenchymal-like stroma of a typical pleomorphic adenoma (Fig. ). The oncocytic cells stained dark blue with PTAH (Fig. ). Tumor showed no immunoreactivity for S-100, HMB-45, Vimentin, CK-20, and SMA. The tumor showed positive immunoreactivity for AE-1/AE-3, CK-7, CEA, EMA and p63 (Fig. ). No cytoplasmic staining for PAS, PAS-D or mucicarmine stains were seen in the oncocytic cells. All 23 dissected cervical lymph nodes were positive for metastatic tumor. The largest node measured 2.8 cm with extracapsular extension into the perinodal soft tissue.
Individual and clusters of cells with abundant pink cytoplasm (H&E ×20)
Fig. 2 a Tumoral thrombi within erythrocytes filled vascular spaces (H&E ×40). b The tumor cells with large, round or polygonal cytoplasm arranged in small clusters with individual cells (H&E ×20). c–d Cells with abundant (more ...)
The pleomorphic adenoma (PA) with myxoid background and ductal epithelial structures (H&E ×10)
The cytoplasm stain dark blue and the granularity is emphasized by PTAH (×40)
The peripheral staining of the tumor nests in the nuclei of the cells with p63 (×20)