PMC4976140_01
Computed tomography (CT) scans. At initial presentation (A and B), the soft tissue mass was 15.7 x 28.6 x 24.2 cm. After a trial of four months of imatinib, the mass had grown to a size of 20 x 37 x 32 cm and demonstrated mass effect on surround organs (C and D).
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A large soft tissue mass in the mid abdomen extending to the upper pelvis was discovered (Fig. 1). A repeat CT scan revealed that the mass had increased significantly to greater than 20 x 37 x 32 cm (Fig. 1) and was causing compression of the small bowel, ureters, and kidneys.
Gross images. The patient's abdominal distension improved when compared preoperatively (A) and postoperatively (B). The resection specimen (C) was 45 x 33 x 23 cm, and it is pictured here immediately after resection with a 15 cm ruler.
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Pathologic analysis of the tumor revealed that it measured 45 x 33 x 23 cm and had a mass of 16.8 kg (Fig. 2).
Histology and immunohistochemistry of resection specimen. Hematoxylin and eosin staining of the specimen confirmed a spindle cell morphology and focal invasion of the appendix on low power (A - 2X, B - 100X). Immunohistochemistry was positive for CD117 (C - 100X) and nuclear beta-catenin (D - 100X).
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Immunohistochemistry was performed and the mass was positive for beta-catenin, weakly positive for CD117 and negative for desmin, smooth muscle actin, CD34, S100 and cytokeratin (Fig. 3).