PMC5203870_01
Contrast-enhanced CT scan of the neck. A well circumscribed, focally enhancing mass is noted in the left pyriform sinus (arrow).
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It was well-defined, hypodense, mostly homogenous, and nonenhancing, with a very focal area of contrast enhancement (Figure 1).
Gross appearance of the specimen.
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Gross examination revealed multiple pieces of soft yellow-tan and glistening tissue measuring 7.5 x 6.5 x 0.5 cm in aggregate (Figure 2).
(A) Hematoxylin and eosin- (H&E-) stained sections showed a hypocellular neoplasm with myxoid background, ropy collagen bundles, and plexiform blood vessels (100x). (B) Mature adipocytes with scattered bland spindle cells (400x).
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On microscopic examination, the pieces are composed of a hypocellular spindle cell neoplasm with abundant myxoid background and plexiform blood vessels (Figure 3(A)). Few mature adipocytes are present as single cells or as small clusters scattered throughout the lesion (Figure 3(B)).
(A) H&E-stained section showed the dendritic cytoplasmic processes of the spindle cells (arrow) (600x). (B) Immunohistochemistry for CD34 also highlights the dendritic cytoplasmic processes.
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The spindle cells have a stellate shape with small oval nuclei, inconspicuous nucleoli, and multiple dendritic cytoplasmic processes (Figure 4(A)). The dendritic cytoplasmic processes were highlighted by CD34 (Figure 4(B)) and vimentin.