PMC4579299_01
Computed tomography without contrast of the abdomen and pelvis was notable for a 4.7 cm mass involving the wall of the terminal ileum, with speckled calcifications, adjacent lymphadenopathy, and a small amount of dense fluid in the pelvis (CT, with arrow).
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A computed tomography of the abdomen and pelvis without contrast was notable for a 4.7 cm mass involving the wall of the terminal ileum, with speckled calcifications, adjacent lymphadenopathy, and a small amount of dense fluid in the pelvis (Figure 1).
On colonoscopy, the luminal surface of the mass was visible through the ileocecal valve and was described as a 4-5 cm friable mass in the terminal ileum (endoscopic view).
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Colonoscopy demonstrated a 4-5 cm friable mass in the terminal ileum (Figure 2), and multiple biopsies of this area were taken.
Laparoscopy revealed a soft, maroon, cystic mass. It was noted to be friable with scant bleeding and to have a tortuous, dilated blood supply (laparoscopic view).
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At the terminal ileum, a soft, maroon, cystic, friable mass associated with scant bleeding and a tortuous, dilated blood supply was noted (Figure 3).
The gross resected specimen included an 11 cm segment of terminal ileum and 4 cm portion of cecum, with a 4 x 3.5 x 3 cm dark red, spongy mass at the terminal ileum (gross specimen).
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The resected specimen was composed of an 11 cm segment of terminal ileum and 4 cm portion of cecum (Figure 4).
Histologic examination of the surgical specimen showed dilated vascular spaces filled with blood and lined by a layer of flat, benign-appearing endothelial cells. The wall of the vascular channels was composed of smooth muscle and fibrous tissue (histology of surgical specimen).
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The walls of the vascular channels were composed of smooth muscle and fibrous tissue (Figure 5).
Histologic review of the original endoscopic biopsy revealed the so-called "endothelialized muscularis mucosae" characterized by a second layer of fibromuscular tissue (long, fine arrow) apposed to the muscularis mucosae (short, thick arrow) (histology of endoscopic biopsy, with arrows).
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On the antiluminal side of the intestinal lumen, this second layer of fibromuscular tissue was lined by a layer of flat endothelial cells (Figure 6).
Upon immunohistochemical staining of the original endoscopic biopsy specimen, this second layer of smooth muscle/fibrous tissue was also lined on the antiluminal side by a layer of flat endothelial cells, highlighted by the endothelial marker CD34 (immunofluorescence staining of endoscopic biopsy).
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Immunohistochemical studies with the endothelial markers CD31 and CD34 highlighted the layer of endothelial cells lining one side of the second fibromuscular layer (Figure 7).