Small bowel lymphatic malformation: Clinical presentation and a comprehensive literature review.

A 47-year-old female patient with a past medical history significant for multiple unprovoked deep veins thromboses, four cesarean sections, inguinal hernia repair, right superficial parotidectomy, and two prior episodes of partial small bowel obstruction managed conservatively presented to our general surgical clinic in May 2021. She reported chronic abdominal pain persisting for five years without associated symptoms such as nausea, vomiting, or rectal bleeding. On clinical examination, the patient appeared hemodynamically stable, with normal vital signs. The abdominal examination was unremarkable, revealing a soft, non-tender, and non-distended abdomen. Laboratory investigations were within normal limits. The initial computed tomography (CT) scan of the abdomen and pelvis, performed in August 2018, demonstrated segmental thickening of the distal small bowel wall, with surrounding fat stranding and a few enlarged lymph nodes. A repeat CT scan in November 2020 revealed a filling defect in the distal small intestine, along with persistent mesenteric fat stranding and multiple lymph nodes, raising a differential diagnosis of inflammatory enteritis vs a neoplastic process. Subsequent magnetic resonance imaging (MRI) of the abdomen identified cystic lesions in the small intestine within the left lower quadrant, raising suspicion for endometriosis. A capsule endoscopy was performed, revealing erythema of the ileal mucosa without additional specific findings. Upper and lower endoscopic evaluations, including gastroscopy and colonoscopy, were unremarkable. Given the persistence of symptoms and inconclusive imaging findings, a diagnostic laparoscopy was planned, with further surgical intervention contingent upon intraoperative findings ( Figure 1 ). Axial contrast-enhanced computed tomography scans of the abdomen showing small bowel lymphatic malformation. A: A lobulated, low-attenuation lesion within the mesentery adjacent to small bowel loops (green arrow), suggestive of a lymphatic malformation; B: The lesion appears to contain internal septations and shows no evidence of enhancement (green arrow), consistent with the imaging features of a mesenteric lymphatic malformation. During the laparoscopy, the small and large intestines were systematically examined. Extensive adhesions were identified and subsequently lysed. A well-defined mass, measuring 8 cm × 6 cm × 3 cm, was observed 2.5 meters proximal to the ileocecal valve. Given its characteristics, en bloc resection of the mass along with a 22 cm segment of the small intestine was performed, followed by a primary end-to-end anastomosis ( Figure 2 ). A resected small bowel loop with a large mass that arises from the mesentery and involves the small bowel wall. Gross examination of the resected specimen revealed a lobulated mass with multiple cystic spaces containing thick, white fluid. Histopathological analysis confirmed the diagnosis of mesenteric and small intestinal lymphatic malformation ( Figure 3 ). Histopathological examination of the resected small bowel mass confirming lymphatic malformation. A: Low power magnification (× 10). Small bowel with multiple dilated, thin-walled lymphatic channels within the submucosa and muscularis layers. The cystic spaces are lined with flattened endothelial cells and contain proteinaceous fluid, consistent with lymphatic malformation (hematoxylin and eosin stain). Scale bar = 100 μm; B: High power magnification (× 40). Lymphatic malformation of the small bowel. Seen are multiple, thin-walled endothelial-lined cystic spaces filled with pale eosinophilic fluid, separated by delicate fibrous septa, with scattered lymphocytes (hematoxylin and eosin stain). Scale bar = 50 μm. Stars (A, B): Cystically dilated lymphatic channels with pale eosinophilic proteinaceous material in lumen. The patient experienced an uneventful early postoperative recovery and was discharged in stable condition on postoperative day 7. However, on postoperative day 10, she presented to the emergency department with signs of superficial surgical site infection. Wound cultures were negative, and the wound was managed with local wound care, irrigation, and a course of antibiotics. The infection resolved, and she was subsequently discharged in good condition. This case highlights the diagnostic challenges of intra-abdominal lymphatic malformations, given their rarity and nonspecific clinical presentation, and underscores the role of surgical resection as the definitive treatment modality.

Our review included 97 patients from 43 studies (46% female, 54% male) with a mean age of 45.6 years (range: 18-76). Notable past histories included abdominal surgeries ( e.g. , hernia repairs, cholecystectomy; 28%), anemia (22%), and smoking (7%). The most common presentation was abdominal pain (74%), often localized to the epigastrium or lower quadrants, followed by gastrointestinal bleeding (melena/hematochezia; 39%), nausea/vomiting (30%), and asymptomatic masses (9%). Symptom duration varied from acute ( 3 months; 44%), with anemia-related symptoms (dizziness, fatigue) persisting for years in some cases ( Figure 4 ; Table 1 )[ 4 , 5 , 7 , 13 - 52 ]. Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for scoping reviews flow diagram. Patient demographics, clinical features, and diagnostic findings F: Female; M: Male; GRAD: Gastroesophageal reflux disease; ADPKD: Autosomal dominant polycystic kidney disease; CHF: Congestive heart failure; Hb: Hemoglobin; GI: Gastrointestinal; LLQ: Left lower quadrant; LUQ: Left upper quadrant; OGIB: Obscure gastrointestinal bleeding; RLQ: Right lower quadrant; RUQ: Right upper quadrant; ALT: Alanine aminotransferase; GGT: Γ-glutamyl transpeptidase; WBC: White blood cell; RBC: Red blood cell; HCT: Hematocrit; LFT: Liver function test; CRP: C-reactive protein; AFP: Alpha-fetoprotein; CEA: Carcinoembryonic antigen; CA: Cancer antigen; CT: Computed tomography; MRI: Magnetic resonance imaging; EGD: Esophagogastroduodenoscopy; CE: Capsule endoscopy; SBE: Small bowel enteroscopy; US: Ultrasound; PET: Positron emission tomography; SBFT: Small bowel follow-through. Physical examination revealed abdominal tenderness (65%), palpable masses (28%), distension (22%), or guarding (13%). Laboratory findings highlighted anemia (hemoglobin < 8 g/dL in 52%), leukocytosis (33%), and elevated amylase/C-reactive protein (17%). Imaging modalities predominantly used CT (87%), supplemented by MRI (26%), ultrasound (22%), and endoscopy (capsule endoscopy/double balloon enterostomy; 39%). Lesions were primarily located in the jejunal mesentery (52%) or ileum (26%), with a mean size of 9.2 cm (range: 0.4-30 cm). Most were multiloculated cystic masses (78%), appearing as thin-walled, fluid-filled lesions with septations (CT/MRI). Multiplicity was noted in 24% of cases ( Table 2 ). Management, histopathology, and outcomes DBE: Double-balloon enteroscopy; LABS: Laparoscopy; RBC: Red blood cell; E. coli : Escherichia coli ; SSI: Surgical site infection. Surgical resection was the primary treatment (91%): (1) Segmental bowel resection (65%) for large or symptomatic masses; (2) Laparoscopic excision (26%) for accessible lesions; and (3) Enucleation (9%) for well-defined cysts. Endoscopic resection (9%) was reserved for small, bleeding submucosal lesions ( e.g. , endoscopic mucosal resection for lymphatic malformations < 2 cm). Incomplete resection occurred in 7% due to adhesions or pancreatic involvement. Histopathology confirmed cystic lymphatic malformation (76%), cavernous (13%), or hemolymphangioma (11%). Postoperative complications occurred in 24%: Infections (13%), anastomotic leaks (4%), and transient pain/fever (7%). Median follow-up was 12 months (range: 3-42 months). Recurrence was observed in 11% ( e.g. , intra-abdominal collections, volvulus), primarily after incomplete resection. No recurrence occurred in fully excised lesions. Resolution of symptoms (pain/bleeding) was achieved in 93%, with normalization of hemoglobin in all anemia cases. A total of 43 studies (41 case reports and 2 case series) were appraised using the Joanna Briggs Institute critical appraisal tools. The quality of reporting was variable across the domains. Patient demographics were fully described in 18 studies (41.9%), partially in 10 (23.3%), and omitted in 15 (34.9%). A clear clinical history and timeline were provided in 17 studies (39.5%). The patient’s condition at presentation was the most consistently reported item, with 34 studies (79.1%) providing full details and 1 (2.3%) providing partial details; however, 8 studies (18.6%) did not address it. Diagnostic tests were clearly described in 34 studies (79.1%), while interventions and post-intervention clinical conditions were detailed in 33 (76.7%) and 30 (69.8%) studies, respectively. Adverse events were documented in only a single study (2.3%). Takeaway lessons were included in 29 studies (67.4%). This assessment highlights significant heterogeneity in reporting standards, particularly concerning demographic details, clinical timelines, and outcomes. Among the 97 cases, only 9 (9.3%) reported specific immunohistochemical markers. These included lymphatic markers (D2-40 in 5 cases), vascular markers (CD31 in 1 case, CD34 in 3 cases, factor VIII in 2 cases), and Ulex europaeus in 1 case. No cases reported using more specific lymphatic markers such as prospero homeobox 1 or vascular endothelial growth factor receptor 3.

In summary, small bowel lymphatic malformations, despite their benign nature, can cause significant morbidity due to mass effect, bleeding, or obstruction. Our case and scoping review underscore key insights. Diagnosis relies on a high index of suspicion, with CT or MRI identifying multiloculated cysts and endoscopy providing supplementary evaluation for mucosal involvement. Management is centered on complete surgical resection, either open or laparoscopic, as it remains definitive. Endoscopic resection should be reserved for small, easily accessible lesions. Prognosis is excellent following complete excision, with 93% symptom resolution and recurrence primarily resulting from residual disease. Future efforts should focus on standardized reporting practices and long-term surveillance to better inform treatment strategies. Clinically, surgeons should maintain a high suspicion for lymphatic malformations when encountering cystic abdominal masses and prioritize radical excision to prevent complications.

Small bowel lymphatic malformations are exceptionally rare in adults, accounting for less than 1% of all lymphatic malformations and approximately 1 in 100000 hospital admissions. Our review, which included 46% female patients with a mean age of 45.6 years, aligns with the reported female predominance (female to male ratio of 1:1). Although traditionally considered congenital, secondary triggers such as abdominal surgery (noted in 28% of cases), inflammation, or trauma may contribute to the development of these lesions in adults[ 53 - 56 ]. Clinically, abdominal pain was the most prevalent symptom, reported in 74% of cases. This pain was often acute due to complications such as bowel obstruction, including volvulus resulting from mass effect, or chronic in nature from the lesion's insidious growth. Gastrointestinal bleeding occurred in 39% of cases and typically arose from erosion into blood vessels or mucosal ulceration[ 38 , 54 , 57 ]. In terms of diagnostics, CT scans were the most commonly used imaging modality, applied in 87% of cases. They revealed characteristic multiloculated, fluid-attenuated masses with septations. MRI, which was underutilized (26%), offered enhanced characterization of complex cysts, particularly through T2-hyperintensity signals. Capsule or balloon-assisted enterostomy was valuable in detecting bleeding or submucosal lesions in 39% of cases, though its sensitivity for mesenteric tumors was limited. Anemia, defined by hemoglobin levels below 8 g/dL, was common in bleeding cases (52%), while tumor markers such as carcinoembryonic antigen were typically within normal limits[ 53 , 56 ]. Surgical resection emerged as the gold standard treatment in 91% of cases. Segmental resection, performed in 65% of these, was preferred for large or symptomatic masses to ensure complete excision. Laparoscopic approaches, used in 26%, offered the benefits of minimally invasive surgery and shorter recovery times but often required conversion to open surgery in complex cases involving adhesions. Endoscopic resection proved effective for small submucosal lesions under 2 cm (9% of cases), although bleeding risks limited its broader applicability[ 38 , 56 ]. Postoperative complications were observed in 24% of patients, including surgical site infections in 13% and anastomotic leaks in 4%. Recurrence occurred in 11% of cases and was primarily associated with incomplete resection, particularly when the lesion was adherent to surrounding structures such as the pancreas. Notably, there were no recurrences following complete excision[ 54 , 56 ]. Histopathologically, cystic lymphatic malformation was the most common variant, seen in 76% of cases, and characterized by dilated lymphatic channels lined by endothelial cells. Hemolymphangioma, a mixed vascular and lymphatic form, was identified in 11% and required immunohistochemical confirmation using markers such as CD31, CD34, and D2-40. However, several important limitations must be acknowledged. First, the included studies consisted predominantly of case reports with significant heterogeneity in reporting standards, particularly concerning demographic details, clinical timelines, and outcomes. Second, as a scoping review of predominantly low-level evidence, formal meta-analysis, calculation of confidence intervals, and stratified statistical comparisons were not methodologically appropriate; our findings should be interpreted as descriptive summaries rather than statistical inferences. Third, immunohistochemical characterization was inconsistently reported, with only 9.3% of cases documenting specific markers, and none reporting contemporary lymphatic markers such as prospero homeobox 1 or vascular endothelial growth factor receptor 3. Finally, publication bias likely led to overrepresentation of symptomatic or complicated cases, while the median follow-up of 12 months may be insufficient to capture late recurrences.

This scoping review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for scoping reviews guidelines to systematically map the existing literature on small bowel lymphatic malformation case reports and case series[ 12 ]. The literature search was conducted using three electronic databases: ScienceDirect, PubMed, and Google Scholar, covering all available literature from inception to August 30, 2024. The search strategy incorporated the following keywords and their synonyms: [(“lymphatic malformation” OR “cystic lymphangioma” OR “lymphangiomatous lesion” OR “mesenteric lymphangioma” OR “intestinal lymphatic malformation”) AND (“small intestine” OR “mesentery” OR “abdomen” OR “small bowel” OR “mesenteric” OR “intra-abdominal”) AND (“diagnosis” OR “surgery” OR “resection” OR “laparoscopy” OR “clinical presentation” OR “imaging” OR “histopathology”) AND (“case report” OR “case series”)]. Two researchers independently and concurrently performed the search. All titles, abstracts, and full texts were screened to identify eligible studies. We included case reports and case series describing adult patients (≥ 18 years) diagnosed with small bowel lymphatic malformation. Articles were included if published in English. We excluded studies that contained duplicate data, did not report small bowel lymphatic malformations, or were published in languages other than English. From each of the eligible studies, the following information was extracted: First author family name, publication year, gender, age, clinical presentation, duration of symptoms, workup and imaging done, management, location and size of the tumor, histology type, follow-up, and survival status of the patients. Given the nature of the included studies (case reports and small series), formal meta-analysis, calculation of confidence intervals, and stratified statistical comparisons were not feasible. Data are presented as descriptive summaries of aggregated case findings.

Lymphatic malformations are rare congenital malformations of the lymphatic system, composed of thin-walled, multiloculated cysts that manifest as benign soft tissue tumors[ 1 , 2 ]. They are lesions of vascular origin with lymphatic differentiation, with approximately 95% occurring in the neck and axilla, while the remaining 5% are found in the chest and abdomen[ 3 ]. Histologically, lymphatic malformations are classified into macrocystic (cysts > 2 cm), microcystic (cysts < 2 cm), or mixed cystic types, with each subtype differing in clinical behavior and prognosis[ 2 , 3 ]. Abdominal lymphatic malformations are extremely rare, accounting for approximately 1 per 100000 hospital admissions[ 4 ]. They have been reported in the mesentery, retroperitoneum, gastrointestinal tract, and intra-abdominal solid viscera[ 5 , 6 ]. The most common locations of intra-abdominal lymphatic malformations include the mesentery, omentum, mesocolon, retroperitoneum, and visceral organs such as the spleen[ 7 , 8 ]. Compared to mesenteric cysts, lymphatic malformations tend to be larger, with a more proliferative and invasive course[ 7 , 8 ]. The clinical presentation of lymphatic malformations varies widely. While some are incidentally discovered on imaging, others present with acute abdominal symptoms[ 7 ]. Most cases remain asymptomatic until the tumor is significant[ 7 ]. Mesenteric lymphatic malformations, in particular, can lead to complications such as intestinal obstruction or volvulus, which may result in infarction[ 4 - 6 ]. The insidious nature of intra-abdominal lymphatic malformations, combined with the spacious abdominal cavity, often leads to a delayed diagnosis[ 8 ]. Additionally, a female predilection has been reported, with a female-to-male ratio of 1:1[ 9 , 10 ]. It is also important to differentiate lymphatic malformations from complex lymphatic anomalies such as generalized lymphatic anomaly, kaposiform lymphangiomatosis, and central conducting lymphatic anomaly, as well as from intestinal lymphangiectasia, since these entities share overlapping features but differ in prognosis and management[ 11 ]. Surgical resection remains the treatment of choice for intra-abdominal lymphatic malformations. While the prognosis is generally favorable, increasing tumor size can make radical resection more difficult and increase the risk of local recurrence. Although successful complete removal has been reported, laparoscopy offers a promising alternative approach for the management of these benign tumors[ 8 - 11 ]. To our knowledge, there are limited scoping reviews that have been conducted specifically on mesenteric and small bowel lymphatic malformations. In this study, we report a case of a female patient with small bowel lymphatic malformation and perform a systematic review and analysis of the English literature.