anemia and thrombocytopenia with increasing transfusion requirements of bleeding. The patients who

have significant pain and early satiety with massively enlarged spleens may benefit by removal of the

mass effect. Finally, MDS is a unique situation in which splenectomy may treat portal hypertension as it

can increase blood flow through a fibrotic and enlarged liver decreasing variceal bleeding and possibly

ascites.113

The Mayo Clinic has updated the use of splenectomy over the past three decades for patients with

myelofibrosis.114 A total of 314 patients have been treated overall with 91 patients treated during the

last 10 years. The primary indications for surgery were mechanical symptoms of compression due to

massive splenomegaly in 49%, severe anemia in 25%, portal hypertension in 15%, and

thrombocytopenia in 11%. Meaningful improvement in symptoms was observed in 30% to 50% of

patients, but the overall complication rate was 28% and there were 6.7% perioperative deaths.114

Furthermore, there is no clear impact on overall patient survival or disease course or the intramedullary

manifestations of myeloid metaplasia after splenectomy. A recent study of 89 patients from Duke

University who underwent splenectomy for myeloid neoplasms similarly demonstrated significant

morbidity and mortality rates in this cohort of patients (38% and 18%, respectively), with

MDS/myeloproliferative neoplasm, anemia, hypoalbuminemia, and abnormal white blood cell count

associated with decreased patient survival rate.115 Given these results, one would have to take into

consideration all factors, including severity of symptoms and comorbidities, before recommending

splenectomy for this hematologic disorder.

Recent treatment strategies have been employed in MDS in the past 10 years. One is antiangiogenic

therapy and the other is immunosuppressive treatment.110 It was recently identified that there was an

increase in neovascularity of the bone marrow in patients with MDS and vascular endothelial cell

growth factor appears to play a prominent role in pathophysiology. Specific antiangiogenic therapy to

block vascular endothelial growth factor (VEGF), including the recently reported trial of thalidomide,

led to independence from needing transfusions in a subgroup of patients with MDS. Interest in

immunosuppressive therapy in MDS occurred because the subset of these patients with refractory

anemia has autoimmune pathophysiology. Young patients or patients with HLA-DR 15 appear to have

autoimmune etiology and have responded to immunosuppressive therapy. A new treatment includes

JAk2 inhibitors (ruxolitinib); in one study, JAK2 V617F mutation was identified in 63% of patients and

independently predicted progression to large splenomegaly.116 Stem cell transplant is considered for

appropriately selected patients with primary myelofibrosis deemed to have high-risk disease as

predicted by the Dynamic International Prognostic Scoring System-plus or with particular genetic

mutational status.117 This scoring system takes into account factors that carry prognostic significance,

including age >65 years, leukocyte count >25,000/μL, hemoglobin <10 g/dL, circulating blast cells

≥1%, and presence of constitutional symptoms.118

Metastatic Disease to the Spleen

The incidence of splenic metastases in autopsy studies of patients coming to malignancy ranges between

2.3% and 7.1%.119 It is rare that splenic metastatic lesions are isolated disease. This commonly occurs in

colon cancer and ovarian cancer. In patients who have multiple areas of intra-abdominal malignancies,

the most common histologies are breast, lung, colorectal, ovarian, and melanoma. There can rarely be

isolated metastasis that may be excised for an increase in disease free survival rate particularly for

colorectal cancer and melanoma.120 Techniques to differentiate benign from malignant processes would

include fine needle aspiration biopsy, magnetic resonance imaging (MRI) with gadolinium looking at

enhancement patterns, and microbubble control to report using ultrasound techniques.121

Metabolic or Infiltrative Diseases

Gaucher disease is an autosomal recessive disorder with a deficiency in the lysosomal hydrolase, βglucosidase, which is encoded by chromosome 1. Gaucher disease is the most common lysosomal

storage disease. β-Glucosidase typically degrades sphingolipids like glucocerebroside. There is a marked

increased incidence of this disorder in Ashkenazi Jews. There are three types of this disease. Type I, the

adult form, comprises 99% of cases and is the one in which splenectomy over the past was useful. The

defect in the acid β-glucosidase causes an accumulation of undegraded glycolipids that are taken up by

the reticuloendothelial cells and result in infiltration of the spleen, liver, and bone marrow. The most

common symptoms with this disease relate to hypersplenism as well as direct effects on massive

splenomegaly. Thrombocytopenia with bleeding problems and anemia causing fatigue are the most

common effects of hypersplenism. Patients also may have such massive spleens that they have early

satiety and weight loss due to gastric compression.

2008

The diagnosis can be confirmed by the measurement of acid β-glucosidase activity in peripheral white

blood cells or cultured fibroblasts. With the cloning of the gene, patients can be screened by molecular

techniques to identify carriers. Prenatal diagnosis is also available by amniocentesis.

In the past, treatment has included supportive care with platelet transfusions as well as erythrocyte

transfusions. Splenectomy was frequently performed for advanced cases and in this disease a significant

experience with partial splenectomy was developed in the early 1990s.122–124 The goals of the subtotal

splenectomy are partially to prevent the complications of overwhelming postsplenectomy sepsis and

partially to protect the lipid and bone marrow by leaving a residual splenic fragment for continued

deposition of lipid. In this disease, the techniques having worked out to safely perform partial

splenectomy leaving a small residual upper pole fragment vascularized from the short gastric vessels.

Recently, it has been established that enzyme replacement with purified placental acid β-glucosidase

is safe with good efficacy. Patients are given between 30 and 60 units/kg of enzyme intravenously

every other week and the symptoms and signs are typically reversed. A recombinant β-glucosidase

(alglucerase) is now available for therapy and the role of splenectomy has been largely displaced by this

medical management.

INCIDENTAL SPLENECTOMY

In a large series evaluating reasons for splenectomy from the combined series from Barnes Hospital and

Brigham & Women’s Hospital, the single most common indication (26% of cases) for removing the

spleen identified was an incidental procedure.24 This would be categorized as an operation primarily for

an adjacent organ or tumor in which the spleen needs to also be removed. The actual primary

treatments of those various disease entities in adjacent organs are subjects of multiple other chapters

within this textbook, but a few comments should be made regarding the reasons for splenectomy and

whether it is always appropriate.

The one common indication for an incidental splenectomy to remove tumors is during removal of the

distal pancreas. For decades, the standard procedure when a distal pancreatectomy was performed was a

splenectomy. The reason for splenectomy is that the splenic vein is intimately associated with the

undersurface of the pancreas and has many direct branches to the pancreatic parenchyma. The splenic

artery generally is superior to the pancreatic border and could be preserved but because of removal of

the splenic vein and for completeness of the resection, an en bloc resection of the distal pancreas and

spleen is typically performed. Because of the interest in splenic preservation due to the incidence of

postsplenectomy infection, two different approaches have been employed to remove the distal pancreas

without removing the spleen. The more technically challenging operation is a distal pancreatectomy

with preservation of the splenic artery and vein. This can be performed only if there is a relatively small

amount of invasive tumor or for benign neoplasia in which the splenic vein can be tediously dissected

away from the pancreatic tissue tying multiple side branches and then dividing the pancreatic

parenchyma leaving the splenic vessel intact. The second spleen preserving distal pancreatectomy

involves ligation of the splenic artery and vein but preservation of short gastric vessels and utilizing

those vessels as collateral inflow and outflow to maintain splenic viability. A recent report

demonstrated no increased risks of preoperative complications or morbidity with this approach.125

Removal of the distal pancreas with splenic preservation has also been recently reported as a

laparoscopic procedure as well.126 For patients with tumors that mandate removal of the lymph nodes

of the splenic hilum or with direct association of the tumor with splenic parenchyma, certainly it is

more appropriate to do an operation based on neoplastic principles and perform a distal

pancreatectomy/splenectomy. In other indications, if the anatomy is appropriate and the completeness

of tumor resection is not compromised, splenic preservation is certainly possible.

Additional procedures in which it is quite common to perform a splenectomy include proximal gastric

cancers. The importance of complete nodal dissection in terms of long-term results in gastric resections

has been debated for several decades. A report from Japan noted that in 20% of proximal gastric

cancers there was positive splenic hilum nodes identified as level X lymph nodes.127 These authors

emphasize the need to perform associated splenectomy with grossly positive nodal disease in the splenic

hilum. A long-term retrospective review from Memorial Sloan-Kettering Cancer Center noted that in

23% of gastrectomies in which complete resection of cancer was accomplished, adjacent organs had to

be removed, the most common being the spleen.128 There was long-term survival in this patient

population, but it was emphasized that this aggressive surgery should be employed only when removal

of all gross disease is achieved.129 A recent randomized study from Korea showed no benefit in doing a

2009