A clinical case of appendiceal mucocele with early and late complications

Clinical History

A woman presented to our hospital complaining with the onset of an acute, widespread, abdominal pain with vomiting. Blood pressure was 150|90 mmHg, laboratory tests showed leucocitosis (12300 GB/µL); no fever. Her abdomen was nondistended but painful in epigastrium and right iliac fossa; surgical history was negative.

Imaging Findings

CT revealed, in the right iliac fossa, a pseudo-cystic formation, with some calcifications at the bottom, measuring about 9 cm cranio-caudally. This formation extended up in the right adnexal site where a fluid-filled nodular formation measuring 2.5 x 2 cm was also evident. Ileum loops in the right abdominal quadrants showed signs of wall oedema with some air-fluid levels, a layer of fluid between them without signs of wall enhancement in post-contrast images. A diffuse and irregular wall-thickening was evident in the splenic flexure, measuring approximately 12 cm cranio-caudally, with many calcifications, resulting in severe stenosis of colonic lumen. This lesion showed an evident vascularisation in post-contrast images. Patient underwent immediate surgery with laparotomic appendicectomy, resection of necrotic ileum and partial left colon resection. Histological examination showed presence of appendiceal mucocele with a low-grade pseudomyxoma peritonei nodule close to right iliac vessels and a left colon diffuse cavernous haemangioma.

Discussion

Appendiceal mucocele (AM) is a rare condition, more frequent in women, with an incidence of 0.2-0.4% of appendicectomies, in which the appendiceal lumen is distended due to an abnormal production of mucus [1, 2]. The term mucocele represents a macroscopical description and can be caused by a variety of different conditions, benign or malignant, resulting in chronical lumen obstruction. Clinical presentation of mucocele is nonspecific; from asymptomatic forms, often diagnosticated incidentally, to abdominal pain conditions, mimicking acute appendicitis, to conditions of acute abdomen with bowel obstruction, intussusception or strangulation [3, 4]. Diagnostic imaging is fundamental in preoperative diagnosis of AM. Ultrasonography is a first level technique in patients with abdominal pain or palpable mass in the right iliac fossa. CT is useful for diagnosis since it allows to detect the lesion as a well-defined cystic mass, frequently with wall calcifications, or to diagnose possible complications. Pseudomyxoma peritonei is the most serious complication of AM; it is characterised by spontaneous or iatrogenic dissemination of mucus with formation of intraperitoneal implants, often in ovarian site [5]. Clinical course of Pseudomyxoma peritonei can be variable and, in aggressive forms, it can result in bowel obstruction, malnutrition and death [6]. CT moreover is useful to study possible gastro-intestinal diseases associated with mucocele since AM is associated in about 20% of cases with neoplasms of gastrointestinal tract. In this case a diffuse cavernous haemangioma coexisted in the splenic flexure. This neoformation looked like a diffuse and irregular vascular wall-thickening of left colon with calcifications and subsequent stenosis of colonic lumen. Cavernous haemangioma is classified among benignant vascular malformations of gastro-intestinal tract [7]. In colon it affects more frequently the rectosigmoid site, but it may involve the bowel in different locations. The clinical presentation consists in recurrent rectal bleeding episodes, anaemia, bowel obstruction or asymptomatic [8]. Colonscopy is the first level diagnostic technique since allows to establish the location and extension of the lesion, which typically looks like red-purplish nodules with vascular congestion. Diagnosis is often difficult and biopsy is not recommended for the risks of bleeding. CT and MRI represent essential preoperatory imaging techniques in order to establish the size of the lesion, the degree of wall thickening and its relations with adjacent structures; the presence of wall calcifications is pathognomonic. The best therapy for AM is appendicectomy with laparotomic approach to reduce the possibiliy of intraperitoneal spreading of mucus [9]. Contrast-enhancement CT is mandatory before surgery.

Differential Diagnosis List

Final Diagnosis

Appendiceal mucocele causing bowel infarction, pseudomyxoma peritonei, cavernous colic haemangioma

URL:	https://www.eurorad.org/case/9832
DOI:	10.1594/EURORAD/CASE.9832
ISSN:	1563-4086