PMC4421923_01
(a) Group of cohesive and pleomorphic tumor cells associated with a small amount of metachromatic fibromyxoid stroma with a vague fibrillary quality. This was a focal finding (Diff-Quik [DQ] stain, x100). (b) A cluster of cohesive and three-dimensional pleomorphic tumor cells showing small fragments of homogeneous metachromatic fibromyxoid stroma in the background. The nuclei are enlarged, hyperchromatic and angulated. Nucleoli are not evident (DQ stain, x100). (c) Loosely-cohesive cluster of tumor cells with large, somewhat irregular nuclei with occasional nucleoli (top of the group). Cytoplasm is scant-moderate and ill-defined with a finely granular texture (DQ stain, x100). (d) Adenocarcinoma cells on a ThinPrep (TP) display coarse irregularly clumped chromatin, occasional nucleoli and dense to granular cytoplasm (TP, Pap stain, x100)
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F1
The cytological findings were not characteristic of any specific parotid gland malignancy, and a diagnosis of primary high-grade adenocarcinoma was rendered [Figure 1a-d].
(a) The resection specimen showed a well-demarcated tumor with a yellow-white cut-surface and minute areas of hemorrhage. (b) Low magnification of carcinoma ex pleomorphic adenoma (PA) admixed with PA. Note the uninvolved intact capsule of PA (H and E, x4). (c) High magnification reveals highly atypical ductal structures and single cells with cellular anaplasia, exhibiting pleomorphic nuclei and eosinophilic cytoplasm (H and E, x40)
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F2
The cut-surface was firm, yellow-white, with minute areas of hemorrhage [Figure 2a]. Initial histologic evaluation, at low magnification, demonstrated a PA with extensive hyalinization and an intact fibrous capsule [Figure 2b]. Mitotic figures were identified, and apoptic cells were present [Figure 2c].