Ileo-Cecal Lipomatosis Mimicking Acute Appendicitis Complicated with Appendicular Abscess: A Case Report

Introduction

Ileocecal lipomatosis is a rare, benign condition characterized by the diffuse infiltration of adipose tissue within the submucosal layer of the ileocecal region [1,2]. Unlike isolated lipomas, which are discrete fatty masses, ileocecal lipomatosis involves a widespread accumulation of fat, often without forming distinct tumors [1]. The etiology of ileocecal lipomatosis remains unclear; however, potential contributing factors include genetic predispositions, metabolic disorders, and chronic inflammatory conditions [3,4]. Notably, associations with familial syndromes, such as Cowden syndrome and Bannayan-Riley-Ruvalcaba syndrome, or hypercholesterolemia have been reported in some cases, although these are not universally present [5,6].

Typically, ileocecal lipomatosis is asymptomatic and is frequently discovered incidentally during imaging or surgical procedures. However, in some instances, the diffuse fat infiltration within the ileocecal region can cause structural changes and exert pressure on adjacent tissues, which may induce localized inflammation and secondary irritation. This can lead to symptoms that mimic appendicitis, including right lower-quadrant pain, nausea, and vomiting [1,7]. The fat infiltration can also lead to mechanical obstruction, narrowing of the intestinal lumen, or changes in blood flow, all of which can aggravate inflammation and contribute to symptoms resembling those of appendicitis. This symptom overlap poses a significant diagnostic challenge, often leading to unnecessary surgical interventions if not correctly identified [7]. Complications associated with ileocecal lipomatosis, such as bowel obstruction or intussusception, can further complicate diagnosis and treatment [7].

Due to these overlapping symptoms, ileocecal lipomatosis presents a diagnostic challenge and can lead to unnecessary surgical interventions if not accurately identified. It is critical to recognize this condition in the differential diagnosis of acute abdominal pain and to evaluate imaging findings carefully to avoid misdiagnosis. Histopathological examination ultimately provides a definitive diagnosis, distinguishing ileocecal lipomatosis from true appendicitis and guiding appropriate patient management [1].

Case Report

Histopathology

GROSS EXAMINATION: The specimen of ileo-cecal resection measured 200×100 mm. The ileocecal valve exhibited yellow fatty infiltration with a polypoidal appearance of mucosal folds. The cecal portion showed necrotic, dark brown, jagged, hemorrhagic areas (Figure 2A–2C).

MICROSCOPIC EXAMINATION: Microscopic examination of the ileum demonstrated intact mucosa with wall edema, vascular congestion, and intravascular lymphocytes. The cecal portion exhibited intact mucosa and wall, with adjacent pericolic fat and mesentery showing extensive edema, vascular congestion, granulation tissue, fibrosis, and a submucosal collection of adipocytes. Another section revealed extensive submucosal lipomatosis characterized by lobules of adipocytes and mild serosal congestion (Figure 3A–3C).

Discussion

Ileo-cecal lipomatosis is a rare, benign condition characterized by the diffuse infiltration of adipose tissue within the intestinal wall, predominantly in the submucosal layer. The etiology of intestinal lipomatosis remains unclear; however, several hypotheses have been proposed, including embryonic displacement of adipose tissue and chronic irritation of the bowel, which can stimulate the abnormal growth of fat cells, as described by Tamvakopoulos et al [6]. Additionally, although associations with familial syndromes and hypercholesterolemia have been reported in the literature [8], such links were not found in this case. The clinical presentation of ileo-cecal lipomatosis often mimics acute appendicitis, primarily due to its location and the associated inflammatory changes. In cases of lipomatosis, the excessive accumulation of adipose tissue within the ileocecal region can exert pressure on surrounding structures, reducing the local blood supply. This mechanical compression can lead to ischemia of the adjacent intestinal mucosa, initiating an inflammatory cascade that produces symptoms similar to those of appendicitis, such as right lower-quadrant abdominal pain, nausea, and vomiting. Additionally, ischemic changes within the adipose tissue itself can promote the release of inflammatory mediators, including cytokines and prostaglandins, which further exacerbate localized inflammation and tissue swelling. Unlike acute appendicitis, where inflammation typically originates from obstruction and infection within the appendix, the inflammatory process in ileo-cecal lipomatosis is primarily driven by tissue hypoxia and mechanical irritation due to the mass effect of fatty infiltration. This inflammation can lead to edema and thickening of the bowel wall, findings often misinterpreted as signs of appendicitis on imaging studies [9]. Over time, recurrent ischemic episodes in the affected tissue can cause areas of necrosis within the lipomatous tissue, intensifying the inflammatory response and creating symptoms that resemble those of an abscess or perforation, which are also complications associated with appendicitis [9]. Furthermore, histopathological examination of resected tissue in ileo-cecal lipomatosis typically reveals submucosal adipose infiltration with minimal-to-no true neutrophilic infiltration, which is characteristic of classic appendicitis. The absence of neutrophilic invasion in ileo-cecal lipomatosis highlights its distinct inflammatory mechanism, as this response is due to tissue degeneration and hypoxia rather than infectious or purulent inflammation. Recognizing these differences in the inflammatory pathway is crucial for distinguishing ileocecal lipomatosis from acute appendicitis [6,9]. The management of ileo-cecal lipomatosis requires accurate preoperative diagnosis to prevent unnecessary surgical procedures. However, as pointed out by Azzam et al, this remains challenging due to the non-specific nature of imaging findings, where CT scans can provide useful information, but plain abdominal films and barium enemas often mimic carcinoma [10]. Thus, intra-operative findings are crucial for diagnosis, although they may not exclude carcinoma based solely on gross examination. This case underscores the importance of considering intestinal lipomatosis in differential diagnoses for acute abdominal symptoms and highlights the need for surgical intervention to manage complications and rule out malignancy. Tailoring the surgical approach based on individual presentations is essential for optimal patient outcomes, as emphasized by Catania et al [11]. Intraoperatively, complications such as a perforated appendix with a necrotic cecal wall may be discovered, as noted in this case. This perforation likely results from the relatively avascular nature of the adipose tissue, leading to ischemia and necrosis of the overlying mucosa, a finding consistent with the report by Puspinder et al [1]. Endoscopic findings in ileocecal lipomatosis can vary significantly. According to a study by Alam et al, mucosa overlying lipomatous lesions may appear normal or present as atrophic, congested, ulcerated, or necrotic, increasing the risk of perforation [12].

Conclusions

In conclusion, ileo-colic lipomatosis is a rare, benign condition that can clinically and radiologically mimic acute appendicitis. This case highlights the importance of considering unusual differential diagnoses in patients presenting with atypical features of appendicitis. Accurate diagnosis through histopathological examination is crucial for appropriate management and optimal patient outcomes.