Tumor on Spleen: Causes, Symptoms, and Treatments

Splenic tumors are uncommon compared with growths in organs like the liver, lungs, or colon, but they span a wide range from harmless masses discovered by accident to aggressive cancers that demand emergency surgery.¹ Whether a splenic mass turns out to be a routine finding or a serious diagnosis depends largely on what kind of tissue it arises from, and the diagnostic journey to figure that out can be surprisingly tricky.

Why the Spleen Rarely Develops Tumors

The spleen sits in the upper left abdomen, tucked behind the stomach. It filters blood, recycles old red blood cells, and harbors immune cells that attack bacteria. Despite handling a large volume of blood every day, the spleen is one of the least common sites for both primary tumors and cancer spread. One proposed reason is architectural: the spleen’s internal structure, a maze of tiny sinusoidal blood vessels, may physically trap and destroy circulating cancer cells before they can take hold.² There is also evidence suggesting that the spleen’s immune environment actively triggers self-destruction signals in tumor cells that arrive through the bloodstream.³ The organ also lacks the kind of incoming lymphatic channels that allow cancer cells easy entry through the lymph system. Together, these features make the spleen a hostile environment for most tumors, but not a completely immune one.

Benign Splenic Tumors

Most splenic masses that show up on imaging are benign. The single most common benign growth is a hemangioma, a tangle of blood vessels that forms inside the spleen. About four out of five people with a splenic hemangioma have no symptoms at all; the mass is usually discovered during a scan done for an unrelated reason.⁴ Small hemangiomas that meet standard imaging criteria can often just be watched over time. The concern with larger ones is that spontaneous rupture has been reported in up to a quarter of hemangioma patients, which can cause internal bleeding serious enough for emergency surgery.

Hamartomas are another benign possibility. These are disorganized clusters of normal splenic tissue rather than true tumors, and they tend to present with mild abdominal pain when they cause symptoms at all.⁵ Lymphangiomas, which are fluid-filled growths involving lymphatic channels, round out the main benign vascular category. Other benign types include littoral cell angiomas and a recently described entity called sclerosing angiomatoid nodular transformation, though all of these are rare even within the already-small world of splenic tumors.⁶

Cysts That Look Like Tumors

Not every mass on the spleen is a tumor. Splenic cysts, both “true” cysts lined with tissue from birth and pseudocysts that form after trauma or infection, are fairly common incidental findings on abdominal imaging. Most are asymptomatic and need no treatment.⁷ Pain can develop if a cyst grows quickly, becomes infected, or ruptures, but a study of patients with large cysts followed for a median of about two and a half years showed no change in median cyst size and no need for intervention during that period.⁸ The important clinical point is distinguishing a simple cyst from a cystic-looking tumor, which usually comes down to imaging characteristics.

Primary Malignant Tumors of the Spleen

When a splenic tumor is cancerous and originates within the spleen itself, the two main categories are lymphomas and vascular cancers. Primary splenic lymphoma accounts for less than two percent of all lymphomas and roughly one percent of non-Hodgkin lymphomas.⁹ It can range from slow-growing types like splenic marginal zone lymphoma to aggressive forms like diffuse large B-cell lymphoma. Because the symptoms tend to be vague, with enlargement of the spleen and general malaise rather than an obvious lump, arriving at the diagnosis is often difficult.¹⁰ Complications like dangerously low blood counts or even splenic rupture can be the first sign.

The most feared primary malignancy is angiosarcoma, a cancer that arises from the blood vessel lining inside the spleen. It is the most common primary malignant non-lymphoid tumor of the spleen, but “most common” here still means extremely rare.⁶ Splenic angiosarcoma is almost universally fatal despite treatment, largely because it tends to spread quickly and frequently presents with spontaneous rupture of the spleen.¹¹ The best survival chances come with catching it early and removing the spleen before rupture occurs.

When Cancer Spreads to the Spleen

A splenic mass can also represent metastatic disease, cancer that started somewhere else and traveled to the spleen. Even so, metastases to the spleen are rare compared with spread to organs like the liver or lungs.¹ When they do occur, the most common primary sources are breast, lung, colorectal, and ovarian cancers, along with melanoma.¹² Solitary metastases to the spleen, meaning no other organ is involved, are especially unusual and tend to come from colorectal or ovarian cancers. In most cases, a splenic metastasis shows up as part of widespread disease rather than as an isolated finding.

Symptoms and How They Show Up

Many splenic tumors produce no symptoms at all and are discovered by coincidence during imaging for something else. When symptoms do develop, the most frequent complaint is abdominal pain, typically a dull ache or fullness in the upper left side of the belly caused by an enlarging spleen pressing on surrounding structures. In splenic angiosarcoma specifically, abdominal pain is reported in roughly 67 to 83 percent of cases.¹³ That pain can shift from mild to severe and sharp if the spleen ruptures.

Other possible symptoms include fatigue, unintended weight loss, and fever, though these occur less consistently and overlap with dozens of other conditions. Some patients develop signs of hypersplenism, where the overactive spleen destroys too many blood cells, leading to anemia, easy bruising from low platelets, or frequent infections from low white cell counts. Because none of these symptoms point specifically to the spleen, doctors often discover a splenic mass only after ordering imaging for persistent, hard-to-explain complaints.

Spontaneous Splenic Rupture

One of the more dramatic presentations of a splenic tumor is spontaneous rupture, meaning the spleen bursts open without any trauma. This is a surgical emergency. In angiosarcoma, the tumor weakens the spleen’s structure so profoundly that rupture and life-threatening internal bleeding can be the first indication that anything is wrong.¹⁴ Case reports describe patients arriving in shock with massive abdominal fluid on emergency CT, requiring immediate surgery to remove the spleen and stop the bleeding.¹⁵ Rupture is not limited to angiosarcoma; it has been reported with large hemangiomas and occasionally with lymphoma as well. Any splenic mass that is growing rapidly or reaching a significant size carries at least some rupture risk.

How Splenic Tumors Are Diagnosed

Imaging is the first step. Ultrasound is typically how a splenic mass is noticed initially, but contrast-enhanced CT is the workhorse for characterizing what the mass might be. A meta-analysis comparing different imaging methods for splenic malignancies found that PET scans had the highest overall diagnostic accuracy, with a sensitivity around 93 percent and a specificity around 83 percent. Contrast-enhanced ultrasound, contrast-enhanced CT, and contrast-enhanced MRI performed comparably, all significantly outperforming non-contrast methods.¹⁶ A separate study focusing specifically on PET/CT found that how intensely a splenic lesion lights up on a PET scan is the single most useful visual clue for distinguishing benign from malignant masses, with lymphomas tending to show higher metabolic activity than metastases.¹⁷

When imaging alone cannot settle the question, a tissue sample is needed. Percutaneous biopsy of the spleen, guided by ultrasound or CT, was once considered too risky because of bleeding concerns. More recent data has shifted that view. One multicenter study found that core needle biopsy of the spleen achieved a diagnostic accuracy of about 92 percent and that serious bleeding requiring intervention was uncommon, though it occurred in a small number of cases.¹⁸ A newer approach uses endoscopic ultrasound to guide the biopsy needle through the stomach wall rather than through the skin. In one comparison, endoscopic ultrasound-guided biopsies had zero clinically significant complications, compared with about 11 percent in the percutaneous group, with similar diagnostic accuracy.¹⁹ In some situations, particularly when the spleen is massively enlarged or the diagnosis remains uncertain after biopsy, surgical removal of the spleen itself serves as both the definitive diagnostic and therapeutic step.

Treatment for Benign Tumors and Cysts

If a benign splenic mass is small and asymptomatic, the standard approach is watchful waiting with periodic imaging. Many hemangiomas, hamartomas, and cysts stay stable for years and never require surgery. When a benign tumor does need removal, because it is large, causing symptoms, or growing, doctors increasingly try to preserve part of the spleen rather than removing it entirely. Partial splenectomy done laparoscopically has been shown to be safe and effective for benign lesions, with patients showing regrowth of remnant splenic tissue afterward and reporting good quality of life.²⁰

Robot-assisted partial splenectomy is a newer option that has shown promising early results. In one series of nine patients with benign lesions, all procedures were completed without conversion to open surgery, and during follow-up there was no recurrence, no new lesions, and no splenic dysfunction.²¹ The appeal of sparing part of the spleen is especially strong in children, where losing the entire organ carries a greater long-term infection risk.

Treatment for Malignant Splenic Tumors

For primary splenic malignancies, the treatment path depends on the tumor type. Splenic angiosarcoma almost always calls for total splenectomy as quickly as possible, ideally before the spleen ruptures. Even with surgery, the prognosis remains poor because of the cancer’s aggressive tendency to metastasize.¹¹

Primary splenic lymphoma, by contrast, has more treatment options. Splenectomy removes the bulk of disease and provides tissue for a definitive diagnosis, but chemotherapy is usually the backbone of treatment. For diffuse large B-cell lymphoma arising in the spleen, the most commonly used regimen mirrors what is used for the same lymphoma elsewhere in the body, centered on a combination known as R-CHOP or newer variations like polatuzumab R-CHP.²² Indolent subtypes like splenic marginal zone lymphoma sometimes overlap with hairy cell leukemia-like disorders, and targeted therapies including BRAF inhibitors and MEK inhibitors have shown effectiveness in relapsed or treatment-resistant cases of those diseases.²³

For metastatic tumors in the spleen, treatment is driven by the original cancer. If the splenic lesion is the only site of metastasis and the primary cancer is controlled, splenectomy may be considered, but in most cases the focus is systemic therapy targeting the primary disease.

Open Versus Laparoscopic Splenectomy

When total splenectomy is needed, the surgical approach matters. Laparoscopic splenectomy, done through small incisions with a camera, consistently shows advantages over traditional open surgery in terms of less postoperative pain, shorter hospital stays, and faster recovery of bowel function.²⁴ A randomized trial comparing hand-assisted laparoscopic splenectomy with open surgery found significant benefits for the laparoscopic approach in pain scores, incision length, and duration of hospitalization.²⁵ There is a practical limit, though: when the spleen is massively enlarged, laparoscopic surgery becomes technically difficult or impossible. Older data showed that spleens above a certain weight required conversion to open surgery in every case.²⁶

Life Without a Spleen

Losing the entire spleen has real long-term consequences. The spleen plays a key role in fighting certain bacteria, particularly encapsulated organisms like the pneumococcus. Without it, the body’s ability to clear those bacteria drops, creating a lifelong risk of overwhelming post-splenectomy infection, a rare but potentially fatal form of sepsis.²⁷ Vaccination against pneumococcus, meningococcus, and Haemophilus influenzae type b is standard before or soon after splenectomy. Some patients also take daily preventive antibiotics, especially in the first year or two.

One reassuring finding from large cohort data is that overwhelming infections remain rare even among people who have not been fully vaccinated, suggesting the absolute risk per year is low, though the consequences of a single episode are severe.²⁸ Beyond infection, splenectomy carries additional risks that get less attention. A Danish population-based study found that people who had undergone splenectomy had a modestly increased risk of blood clots in both the regular venous system and the portal vein system, as well as a higher adjusted risk of stroke compared with the general population.²⁹ The thromboembolic risk is another reason clinicians prefer partial splenectomy when the underlying disease allows it.³⁰

Splenic Tumors in Children

Splenic masses in children are overwhelmingly benign. A series of 24 pediatric patients who underwent laparoscopic surgery for splenic masses found that the vast majority were epithelial cysts, lymphangiomas, hamartomas, and hemangiomas. Most were asymptomatic and discovered by accident. No postoperative complications or tumor recurrence were observed.³¹ Among children with hamartomas specifically, symptoms tend to appear more often than in adults, particularly when the hamartoma is large or there are multiple lesions. Anemia, low platelets, and an enlarged spleen are the most common findings, and these typically resolve after surgical removal.³²

Malignant splenic tumors in children are extremely rare but behave aggressively when they do occur. Pediatric splenic angiosarcoma almost always presents with disease that has already spread, with the liver being the most commonly involved secondary site. Durable remission has been achieved in only a small fraction of reported pediatric cases.³³ For benign lesions, partial splenectomy is especially appealing in children because preserving even a portion of the spleen maintains some protective immune function, and studies so far show no recurrence after partial removal of benign tumors.³⁴

The Role of Immune Suppression

One recurring theme in splenic malignancies is the connection to immune system health. People with weakened immune systems, whether from organ transplantation, HIV, or immunosuppressive drugs, face a higher risk of developing certain lymphomas, including those that can arise in the spleen. Epstein-Barr virus, which most people carry harmlessly, can drive lymphoma development when immune surveillance breaks down.³⁵ Radiation exposure has also appeared in case histories of patients who later developed splenic lymphoma, though the rarity of the disease makes it hard to establish firm causal links from individual reports. For most people diagnosed with a splenic tumor, no clear cause is ever identified, and the mass turns out to be a benign vascular growth or a cyst that posed no danger.