Giant Omental Lymphangioma Presenting With Abdominal Pain and Intra-Cystic Hemorrhage in an Adult: A Case Report

Our plain-English summary of Giant Omental Lymphangioma Presenting With Abdominal Pain and Intra-Cystic Hemorrhage in an Adult: A Case Report, by R. Hashizume, H. Imai, A. Hayashi, et al (Curēus, 2026).

The study

• Authors: R. Hashizume, H. Imai, A. Hayashi, T. Tanigawa, F. Ito, N. Noda, A. Okamoto, Y. Kanamori, M. Hamaji
• Journal: Curēus
• Published: 2026;18(7):e113140
• Type of article: Case report
• Read it: PubMed · Publisher · Free full text

Abstract

Lymphangiomas are benign tumors of lymphatic origin that usually arise in the neck and axilla during childhood; intra-abdominal involvement is rare, and an omental origin in an adult is exceptional. Because imaging features are non-specific, preoperative diagnosis is difficult, and intra-cystic hemorrhage can transform an otherwise indolent lesion into a surgical emergency. We report the case of a 46-year-old man who presented with sudden right lower-quadrant abdominal pain and a soft, mobile, tender right-abdominal mass. Contrast-enhanced computed tomography (CT) and magnetic resonance imaging (MRI) revealed a giant (approximately 25 cm), thin-walled, multilocular cystic mass containing a hematoma, with enhancement of the cyst walls but not the internal component, and feeding vessels arising from the greater omentum. Tumor markers were normal apart from mildly elevated carbohydrate antigen (CA) 125. Because malignancy could not be excluded, open resection was performed; the tumor arose from the greater omentum without invading adjacent organs and was completely excised. Histopathology confirmed an omental lymphangioma. The acute presentation was attributable to intra-cystic hemorrhage with a focal, self-sealed rupture superimposed on an indolent lesion. Because cross-sectional imaging cannot reliably distinguish lymphangioma from other cystic lesions, an immunohistochemical panel combining lymphatic and vascular endothelial markers (D2-40, CD31) with mesothelial markers (calretinin, WT-1) was decisive in excluding a mesothelial-lined cyst and mesothelioma. Omental lymphangioma should be considered in the differential diagnosis of a giant intra-abdominal multilocular cystic mass in adults, including those presenting acutely, and complete excision is both diagnostic and curative.

Copyright © 2026, Hashizume et al.

In plain English

This case report describes one patient, a 46-year-old man treated in Japan. It does not mention asbestos. He had sudden, severe lower-right abdominal pain and a tender lump. Scans showed a large, thin-walled cyst with many compartments. It contained what looked like a blood clot and was fed by blood vessels from the greater omentum, a fatty layer inside the abdomen. Because cancer could not be ruled out, surgeons removed the whole mass. It measured 19.6 by 13.5 cm and had not invaded nearby organs. Staining showed that the cells lining the cyst were positive for lymphatic and blood-vessel markers (D2-40, CD31) and negative for mesothelial markers (calretinin, WT-1). This confirmed a benign omental lymphangioma and, according to the authors, excluded a mesothelial-lined cyst or mesothelioma. The authors concluded that the pain may have been caused by bleeding inside the cyst with a small rupture that sealed itself, though they called this mechanism inferential. They also concluded that complete removal is curative. Follow-up so far covered only about one month.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: case report (single patient)
• Who was studied: One 46-year-old man, a former smoker who worked as a care worker, referred to a hospital in Ise, Japan, with sudden right lower-quadrant abdominal pain
• Exposure: No asbestos or other fiber exposure is reported. The article gives only the patient's occupation (care worker) and his past surgery, abdominal trauma and smoking history.
• Main results:
  • CT showed a thin-walled, multilocular cystic mass in the right abdomen containing material consistent with a hematoma (blood clot)
  • The tumor marker CA125 was mildly elevated in this patient at 35.2 U/mL; the reference limit was 35 U/mL or less
  • At open surgery, the tumor arose from the greater omentum and did not adhere to or invade the colon or mesentery. It was completely excised without removing other organs.
  • The resected specimen was a 19.6 × 13.5 cm multilocular cystic mass with a partial hematoma
  • At surgery, a thinned, defective area of the cyst wall was found where it was adherent to the abdominal wall, and hemorrhagic content similar to the ascites was released from it
  • The cells lining the cyst were positive for D2-40 and CD31, focally positive for CD34, and negative for calretinin and WT-1, confirming a lymphangioma of the greater omentum
  • The authors state that the absence of calretinin and WT-1 expression excluded a mesothelial-lined cyst and cystic mesothelioma
  • The patient was discharged on postoperative day 9. At about one month after surgery he was asymptomatic with unremarkable laboratory findings; no imaging was done at that visit.
• The authors' conclusion: The authors concluded that omental lymphangioma should be considered when an adult has a giant multilocular cystic abdominal mass, including with an acute presentation. They added that diagnosis rests on histopathology with immunohistochemistry, and that complete excision is curative and provides the definitive diagnosis.
• Limitations the authors state:
  • A single case cannot establish how often acquired mechanisms occur or the best surveillance interval, and the proposed acquired cause remains speculative
  • Follow-up is limited to about one month, so the long-term course and recurrence risk remain uncertain
  • The explanation of bleeding with a self-sealed rupture is inferential
  • As a single case report, its generalizability is limited

Topics

Medical terms in this study, explained in our Lexicon: Omentum, Tumor Marker, Histopathology, Podoplanin (D2-40), Calretinin, Wilms Tumor 1 (WT-1), Mesothelioma, Differential Diagnosis.

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• Differentiating a large abdominal cystic lymphangioma from multicystic mesothelioma: report of a case — H. Nagata, Y. Yonemura, et al. (2014)
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