Watermelon stomach is a condition in which small blood vessels in the lining of the stomach become abnormally dilated and fragile, forming visible red streaks that look strikingly like the stripes on a watermelon rind. Its medical name is gastric antral vascular ectasia, or GAVE. The condition causes slow, chronic bleeding from these damaged vessels, often leading to iron-deficiency anemia that can become severe enough to require regular blood transfusions. Though uncommon, GAVE is increasingly recognized as an important and treatable source of gastrointestinal blood loss, especially in older adults.
Where the Name Comes From
The nickname “watermelon stomach” dates to 1984, when researchers described the distinctive appearance they saw through an endoscope: longitudinal red folds converging on the pylorus, the muscular opening between the stomach and the small intestine.1Annals of Medicine and Surgery. Gastric antral vascular ectasia (Watermelon stomach); an unusual cause of upper gastrointestinal bleeding in elderly: A case report Those red stripes are clusters of widened blood vessels sitting just below the stomach’s surface, and the resemblance to a watermelon is hard to miss once you see the endoscopy images.
Not every case looks like the textbook picture, though. Gastroenterologists recognize two main patterns. The classic “striped” type has flat or raised red lines radiating outward from the pylorus. A second “punctate” or diffuse type shows sharply defined red spots scattered across the antrum in a honeycomb-like pattern rather than organized lines.2PubMed Central. Influences of etiology and endoscopic appearance on the long-term outcomes of gastric antral vascular ectasia The punctate form can be harder to identify because it does not scream “watermelon,” and it tends to be linked with different underlying conditions, particularly liver cirrhosis.
Symptoms and Who Is Most Affected
GAVE rarely announces itself with dramatic symptoms. The hallmark is chronic, slow blood loss from the stomach lining, often so gradual that you do not notice bleeding at all. Instead, the first sign is usually anemia: fatigue, weakness, shortness of breath on exertion, pallor. Stool tests come back positive for hidden (occult) blood, and blood work shows iron stores dropping steadily.3PubMed. Treatment of watermelon stomach Some people develop anemia severe enough to need repeated transfusions before a cause is found. Less commonly, GAVE can cause visible bleeding, with dark or bloody stools, or vague upper abdominal discomfort.
The typical patient, when liver disease is not involved, is an older woman. Studies describe the average age at diagnosis as around 73, with women making up roughly seven out of ten cases.4PubMed Central. Gastric antral vascular ectasia (watermelon stomach)-an enigmatic and often-overlooked cause of gastrointestinal bleeding in the elderly That demographic profile can actually delay diagnosis, because iron-deficiency anemia in older women gets attributed to many other things before someone thinks to look at the stomach lining through an endoscope. The condition often coexists with autoimmune disease, cirrhosis, or both.5The American Journal of Gastroenterology. The watermelon stomach: clinical presentation, diagnosis, and treatment
What Causes Watermelon Stomach
The honest answer is that no one is entirely sure. The mechanisms behind GAVE remain poorly understood despite decades of study. Several theories have been proposed, including mechanical stress on the stomach lining from abnormal contractions, hormonal factors, autoimmune processes that damage blood vessels, and changes in blood flow patterns within the stomach wall.6PubMed Central. Diagnosis and management of gastric antral vascular ectasia None of these alone explains why some people develop GAVE while others with the same risk factors do not.
One prominent idea centers on the antrum itself. This is the lower section of the stomach, where muscular contractions are strongest as food gets pushed toward the small intestine. The thinking goes that repeated mechanical strain on the antral mucosa, combined with some underlying vulnerability in the blood vessels, leads to the dilation and fragility that define GAVE. Reduced stomach acid production (achlorhydria or hypochlorhydria) is also commonly seen alongside watermelon stomach, though whether that is a cause, a consequence, or simply a co-traveler remains unclear.
Conditions Commonly Linked to GAVE
Watermelon stomach rarely shows up in isolation. It tends to cluster with a handful of other medical conditions, and understanding those associations matters because they affect both how the condition behaves and how aggressively it needs to be treated.
- Liver cirrhosis: Cirrhosis is one of the most common companions of GAVE, and distinguishing watermelon stomach from a separate condition called portal hypertensive gastropathy (PHG) is a key part of diagnosis. Both can cause stomach bleeding in people with liver disease, but they arise from different mechanisms and require different treatments.
- Autoimmune disease: A wide range of autoimmune conditions have been reported alongside GAVE. Systemic sclerosis (scleroderma) has the strongest and best-studied link, but autoimmune thyroid disease, pernicious anemia, and other connective tissue disorders also appear frequently.
- Chronic kidney disease: GAVE has been documented in patients with end-stage kidney disease, though reports are scarce and the true incidence in this population remains unknown.7Indian Journal of Nephrology. Watermelon stomach in end-stage renal disease patient
The scleroderma connection deserves particular attention. In one study of over 260 scleroderma patients, about 6% had watermelon stomach, and in the vast majority of those cases the scleroderma had appeared first.8PubMed. Watermelon stomach in systemic sclerosis: its incidence and management Scleroderma involves widespread fibrosis and vascular damage, so it makes biological sense that blood vessels in the stomach would be affected. Researchers have found that scleroderma patients carrying a specific antibody, anti-RNA polymerase III, face a substantially higher risk of developing GAVE. In one analysis, this antibody was present in about 71% of scleroderma patients who had GAVE compared with only 19% of those who did not, and the antibody remained a strong independent predictor even after adjusting for other factors.9PubMed Central. Gastric Antral Vascular Ectasia in Systemic Sclerosis: Association with Anti-RNA Polymerase III and Negative Anti-Nuclear Antibodies
That antibody finding has practical value. A separate study observed that all four scleroderma patients who developed GAVE in their cohort carried anti-RNA polymerase III antibodies, and all were diagnosed with GAVE within the first year of their skin disease, typically around seven months in.10The Journal of Rheumatology. Anti-RNA Polymerase III Antibodies as a Risk Marker for Early Gastric Antral Vascular Ectasia (GAVE) in Systemic Sclerosis For scleroderma patients with this antibody and rapidly progressing skin involvement, early screening for GAVE could catch the problem before serious anemia sets in.
How Watermelon Stomach Is Diagnosed
Diagnosis starts with an upper endoscopy. A gastroenterologist passes a flexible scope into the stomach and looks directly at the antral lining. The classic striped pattern is often distinctive enough to make the diagnosis on sight.11PubMed Central. Insights into the management of gastric antral vascular ectasia (watermelon stomach) But when the appearance is ambiguous, particularly with the diffuse punctate form, a biopsy can confirm it. Under the microscope, GAVE has a characteristic set of features that set it apart from ordinary gastritis: dilated mucosal blood vessels, tiny blood clots (fibrin thrombi) inside those vessels, and an unusual proliferation of spindle-shaped cells growing into the stomach lining.12PubMed. Endoscopic biopsy is diagnostic in gastric antral vascular ectasia. The “watermelon stomach” Earlier pathology studies confirmed that the blood vessel cross-sectional area was measurably larger and fibrin thrombi were far more common in GAVE tissue compared with normal stomach biopsies.13PubMed. Gastric antral vascular ectasia. A histologic and morphometric study of “the watermelon stomach”
Endoscopic ultrasound has also been explored as a diagnostic tool, with characteristic thickening of the inner stomach wall layers visible on imaging that correlates with both the endoscopic appearance and the tissue findings.14PubMed. Endoscopic ultrasound appearance of watermelon stomach In practice, though, standard endoscopy with or without biopsy remains the workhorse for diagnosis.
Telling It Apart From Portal Hypertensive Gastropathy
One of the most clinically important distinctions is between GAVE and portal hypertensive gastropathy, or PHG. Both conditions cause abnormal-looking stomach mucosa and can lead to bleeding, and both are found in patients with liver disease, which is why they get confused. But they are fundamentally different problems with different treatments.
PHG, by definition, requires portal hypertension, the elevated pressure in the portal vein that accompanies cirrhosis and other liver conditions. GAVE does not require cirrhosis or portal hypertension at all.15PubMed. the management of portal hypertensive gastropathy and gastric antral vascular ectasia in cirrhosis The distinction matters enormously for treatment: PHG is managed by lowering portal pressure, usually with medications or sometimes shunt procedures, while GAVE is treated with endoscopic ablation of the abnormal vessels. Applying the wrong treatment to the wrong condition will not help and may waste time while the patient continues to bleed. When the endoscopic appearance is not clear-cut, biopsy can resolve the question.
Endoscopic Treatment
The first-line treatment for watermelon stomach is endoscopic, meaning the same scope used to diagnose the condition is also used to treat it. The goal is to destroy or seal off the fragile, bleeding blood vessels on the stomach surface. Two main techniques dominate current practice.
Argon plasma coagulation, or APC, has been the most widely used approach for years. It works by directing a jet of ionized argon gas at the abnormal tissue, delivering heat that cauterizes the bleeding vessels. APC is effective and widely available, and many patients see meaningful improvement in their hemoglobin levels and reduced need for transfusions. The downside is that it often requires multiple sessions to get the bleeding under control, and the abnormal vessels can recur.
Endoscopic band ligation, or EBL, is a newer alternative that applies small rubber bands to the affected tissue, cutting off blood flow to the abnormal vessels. Head-to-head comparisons have generally favored EBL. A systematic review and meta-analysis of randomized trials found that EBL achieved higher rates of complete eradication of the lesions and lower rates of rebleeding than APC. Patients treated with EBL also required fewer blood transfusions and fewer hospitalizations, and the number of endoscopic sessions needed to fully treat the lesions was lower with EBL. Complication rates were similar between the two techniques.16PubMed Central. Endoscopic Band Ligation Versus Argon Plasma Coagulation in the Treatment of Gastric Antral Vascular Ectasia: A Systematic Review and Meta-Analysis of Randomized Controlled Trials
Individual randomized trials have reinforced those findings. One trial found that EBL achieved endoscopic clearance in about 87% of patients at three months versus roughly half with APC, and rebleeding episodes were fewer in the EBL group during the first three months of follow-up.17PubMed Central. Endotherapeutic approach to gastric antral vascular ectasia: Argon plasma coagulation vs. endoscopic band ligation: Randomized clinical trial Another trial confirmed that both techniques improved hemoglobin and reduced transfusion needs with similar complication profiles, but EBL required fewer sessions to reach remission.18The Egyptian Journal of Internal Medicine. Safety and efficacy of endoscopic band ligation versus argon plasma coagulation in management of gastric antral vascular ectasia: randomized clinical trial In practice, the choice between APC and EBL often depends on the endoscopist’s experience and what equipment is available, but the evidence is tilting toward EBL as the preferred option when both are accessible.
Radiofrequency ablation, which uses heat generated by radio waves to destroy abnormal tissue, has also been explored for GAVE that does not respond well to APC or EBL. Case series have reported it as a viable option, though the evidence base is much smaller and it remains a second-line or experimental choice at most centers.19PubMed Central. Radiofrequency ablation using Barrx(®) for the endoscopic treatment of gastric antral vascular ectasia: a series of three cases and a review of the literature on treatment options
When Endoscopy Is Not Enough
Some patients keep bleeding despite multiple rounds of endoscopic treatment. For those cases, a few other approaches exist, though none of them has a strong evidence base.
On the drug side, octreotide, a synthetic hormone that reduces blood flow to the gut, has shown promise in controlling recurrent bleeding from GAVE, particularly in patients who are too frail or medically complex for repeated procedures or surgery.20PubMed. The efficacy of octreotide therapy in chronic bleeding due to vascular abnormalities of the gastrointestinal tract Thalidomide, known for its anti-angiogenic properties (it inhibits the growth of new blood vessels), has been tried in isolated cases of endoscopy-resistant GAVE. In one reported case, a patient who had failed endoscopic treatment became transfusion-independent within three months of starting thalidomide and maintained adequate hemoglobin for at least nine months.21PubMed. Treatment of chronic transfusion-dependent gastric antral vascular ectasia (watermelon stomach) with thalidomide These drug therapies are used off-label and on a case-by-case basis, not as standard-of-care recommendations.
Surgery, specifically removal of the antrum (antrectomy), is considered a last resort when everything else has failed. It is the most definitive treatment since it removes the tissue where the abnormal vessels sit, and reports suggest that patients who undergo surgery tend to achieve more stable hemoglobin levels and freedom from transfusions compared with those managed endoscopically over the long term.22PubMed Central. Successful Surgical Management of Gastric Antral Vascular Ectasia in a Patient with End-Stage Renal Disease: A Case Report and Literature Review The trade-off is the risk of a major abdominal operation in patients who are often elderly and medically fragile. Surgery tends to be reserved for patients who are accumulating transfusions faster than endoscopic sessions can keep up with.
Why It Takes So Long to Diagnose
One of the frustrating aspects of watermelon stomach is how long patients can go undiagnosed. The slow, invisible nature of the bleeding means that a person may receive months or even years of iron supplements and transfusions before anyone performs the endoscopy that reveals the cause. Since the condition primarily affects older women, and iron-deficiency anemia in that group has a long list of more common explanations, GAVE is often one of the last things considered. It has been described as an “often-overlooked” source of bleeding in the elderly for this reason.4PubMed Central. Gastric antral vascular ectasia (watermelon stomach)-an enigmatic and often-overlooked cause of gastrointestinal bleeding in the elderly
The diffuse, punctate form of GAVE adds another layer of diagnostic difficulty. Because it lacks the dramatic striped pattern that immediately triggers recognition, it can be mistaken for ordinary gastritis or PHG during endoscopy. Biopsy is especially useful in these ambiguous cases, since the microscopic features of GAVE are distinctive enough to make the diagnosis reliably even from small tissue samples.12PubMed. Endoscopic biopsy is diagnostic in gastric antral vascular ectasia. The “watermelon stomach”
The Role of Artificial Intelligence in Future Diagnosis
Given the diagnostic challenges, there is growing interest in whether artificial intelligence could help. The idea is to build large image databases of GAVE endoscopy findings and cross-reference them with CT imaging and other data, allowing machine-learning tools to flag suspicious cases that a human eye might miss or misclassify.23PubMed Central. A delayed gastric antral vascular ectasia: A case report and literature review AI-assisted endoscopy is already being tested for detecting polyps and other lesions in the gastrointestinal tract, so extending that capability to GAVE is a natural next step. Whether it will meaningfully shorten time to diagnosis remains to be seen, but for a condition where the main barrier is simply thinking to look for it, any tool that nudges clinicians toward the right diagnosis earlier could make a real difference for patients living with unexplained anemia.