Andrea Agualimpia Garcia, MD
University of Texas Health Science Center
San Antonio, Texas

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Clinical History

70 year-old male with a past medical history of hypertension, hyperlipidemia and greater than 40 pack-year smoking history. Family history is significant for three siblings diagnosed with prostate, breast and lung cancer.

The patient noticed a palpable nodule in the left preauricular region and presented to primary care who consulted the ENT service. A computer tomography (CT) scan revealed a poorly defined lesion at the left superior parotid gland. Imaging differential diagnosis included a pathologic lymph node and a primary salivary gland tumor. Fine needle aspiration (FNA) was recommended for definitive diagnosis. FNA and core biopsy of left parotid gland was performed.

Educational Objective 1: Recognize presentation of this lesion.

Educational Objective 2: Describe general cytomorphological features of this lesion.

Educational Objective 3: Describe and identify immunohistochemistry markers and special stains used for this lesion.

Educational Objective 4: Recognize diagnostic pitfalls of this lesion.

Cytopathology Features

The aspirates show groups of cells with prominent nucleoli and abundant cytoplasm. There is sparse peripheral acellular basement membrane material present. P63 and calponin highlight the myoepithelial cells and AE1/AE3 highlights the luminal epithelium. The findings are consistent with the diagnosis of epithelial-stromal neoplasm of the parotid gland on fine needle aspiration.  Gross examination of the resected left parotid mass demonstrated a 0.8 x 0.6 cm tan brown nodule. The histology depicts a multilobulated lesion with a pushing infiltrative border and biphasic morphology with a ductal epithelial component as well as a myoepithelial component. AE1/AE3 and other cytokeratins (not shown here) highlight the ductal component, whereas P63, calponin, and SMA (not shown here) highlight the myoepithelial cells.

 

Figure 1:  10x Diff Quick stained FNA: The cells have nucleoli and scattered nuclear enlargement.

Figure 2:  10x Diff Quick stained FNA -Epithelial population with cells with round/oval nuclei. Some peripherally located acellular pink material present.

Figure 3:  20x Diff Quick stained FNA – Cellular specimen consisting of larger clear cells with moderate amount of cytoplasm and vesicular nuclei with nucleoli. Occasional smaller dark cells with less cytoplasm are seen in the lower left of the image.

Figure 4: 10x H&E Surgical Resection Specimen

Figure 5: 10x P63 Immunohistochemistry (IHC) highlights the myoepithelial cells.

Figure 6: 10x AE1/AE3 Immunohistochemistry (IHC) highlights the epithelial cells.