Retention mucocele of distal viable remnant tip of appendix: An unusually rare late surgical complication following incomplete appendectomy

Figure 1 Ultrasonography shows a hypoechoeic space occupying lesion measuring 6. 5 cm × 3 cm × 6 cm in the right lumbar region anterior to right kidney (arrows). Internal echoes and fluid components are seen within the cystic mass (arrowheads) (A-C).

Figure 2 CECT shows a well defined hypodenseblind ending tubular lesion (arrows) measuring 6. 8cm × 3.1cm × 3.0cm (CT value + 32HU) in the right lumbar region lateral to ascending colon along the antimesenteric border not communicating with the lumen of colon(A-C). C=Caecum, AC=Ascending colon, M=Mucocele, A=Distal appendiceal remnant not communicating with caecal lumen.

Figure 3 Macroscopic/gross pathology. A: Perioperative photograph shows a turgid cystic mass measuring 6cm × 5cm × 3cm in the distal appendicular remnant with a separate mesentery located adjacent to the pulled up caecum and not communicating with lumen of caecum (arrows); B: Resected specimen shows cystic dilatation of turgid distal appendicular remnant with surrounding fibrofatty, mesenteric, and omental tissues (arrow); C: Cut open resected specimen shows protruding mucinous material from the lumen of cystically dilated turgid distal appendicular remnant (arrow).

Figure 4 Histopathological microphotographs of mucinous cystadenoma of appendix. A: Low power microscopic view. Appendicular lumen shows mucinous secretions (1) with no epithelial elements. Mucosa lined by a single layer of mucinous columnar epithelium with basally situated nuclei (2) does not show any atypia with underlying lymphoid aggregataes (3). B,C: High power microscopic view. Appendiceal lumen shows lakes of mucin (1) with no epithelial elements. Mucosa lined by a single layer of mucinous columnar epithelium with basally situated nuclei (2) does not show any atypia with underlying lymphoid aggregates(3).