PMC7298332_01
Contrast-enhanced computed tomography image revealing a hypodense cystic mass lesion lateral to the caecum, not communicating with the lumen.. The lesion has a weakly enhancing wall with scattered mural calcification and a prominent structure located along the retroperitoneum.. In axial view (a) and in coronal view (b).. Magnetic resonance imaging revealing a cystic mass lesion that was markedly hypointense on T1-weighted images (c) and hyperintense on T2-weighted images (d).. M: cystic mass, P: prominent structure.
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Abdominal contrast-enhanced computed tomography showed a well-defined hypodense (15-20 Hounsfield units) cystic mass lesion measuring approximately 7.0 x 12.0 cm lateral to the cecum, which appeared not to be communicating (Fig. 1).
Schematic illustration of the ileocecal lesion and prior open appendectomy.. The cystic mass with a prominent structure.. M: cystic mass, P: prominent structure, C: caecum, AC: ascending colon.
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During tissue peeling, the appendix accidentally detached, and the tip was lost (Fig. 2).
Macroscopic view of the opened ileum, caecum, cystic mass lesion (a).. It revealed a distended mucus-filled cystic mass lateral to the caecum with no communication with the lumen.. The lesion had a prominent structure (b).. P: prominent structure.
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Gross pathologic examination revealed a distended mucus-filled lesion lateral to the cecum without communicating with the lumen (Fig. 3).
Macroscopic view of the long-axis cross section of the opened prominent structure (a).. Low power microscopic view of the prominent structure tip revealed mucinous material and surrounding muscular layer (b).. Mucosa layer was almost lost; however, the muscular layer was confirmed over the entire prominent structure surface.
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The prominent structure had almost no mucosa layer; however, the muscular layer remained, suggestive of distal appendiceal remnant (Fig. 4).
Schematic illustration of mucus-filled cystic mass formation.. Distal remnant of appendiceal tip maintained its vascularization and secreted mucus continuously, leading to cystic formation.. M: cystic mass.
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The patient was diagnosed with a mucus-filled lesion rose from the distal viable remnant tip of the appendix (Fig. 5).