Mesenteric Tumors

Updated: Nov 14, 2022
Author: Neal E Seymour, MD; Chief Editor: John Geibel, MD, MSc, DSc, AGAF 

Overview

Practice Essentials

This article discusses mass lesions of the mesentery, including nonprimary tumors with manifestations related to the mesentery. Mesenteric tumors are uncommon lesions that are generally considered inclusive of similar lesions of the omentum. Primarily anecdotal references to this class of tumors have been made since the beginning of the 20th century. In 1936, Hart provided the earliest clear description of solid mesenteric tumors. As experience has accumulated in treating these lesions, a more complete picture of the various disease types that manifest as mesenteric masses has emerged.

Mesenteric tumors may be cystic or solid, and they may demonstrate malignant or benign clinical behavior. Although uncommon, they are encountered in all age groups from infancy to the very elderly. These tumors should be considered as an explanation for a palpable abdominal mass, but they are most commonly brought into the differential diagnosis of abdominal pathology once a suggestive radiologic study or an abdominal operation has been performed. An increased awareness of neoplastic and nonneoplastic processes that result in mesenteric masses aids the clinician in recognizing these diseases.

Mesenteric masses and lymphadenopathy shown to be related to infection are best treated with appropriately directed antimicrobial therapy. (See Treatment.) Sclerosing mesenteritis has been treated with antimetabolites. Mesenteric lymphoma is treated with cytotoxic chemotherapy. Mesenteric desmoid tumors have been reported to respond to various pharmacologic treatments; radiation therapy may be an option for unresectable, partially resectable, or recurrent mesenteric desmoid tumors.

Surgical treatment of benign mesenteric masses generally consists of local excision for smaller lesions. For malignant mesenteric tumors, the therapy of greatest demonstrated benefit is surgical, with the goal of removing gross disease with tumor-free margins of resection; this may involve en-bloc resection of other involved structures. Mesenteric desmoid tumors are very difficult lesions to treat surgically. Mesenteric lymphoma is not usually treated surgically; surgery is best used diagnostically when the diagnosis is probable but uncertain. Mesenteric carcinoid tumors are treated by resecting the mesenteric masses. Treatment of Castleman disease should consist of local resection of the lymph node mass.

Anatomy

The mesentery of the gastrointestinal (GI) tract consists of a contiguous, fibrofatty, fanlike structure containing arterial, venous, lymphatic, and neural structures coursing to and from the intestine, along the intestine's entire length.

The small-bowel mesentery and portions of the large-bowel mesentery are mobile within the peritoneal cavity. The mesenteries of the ascending and descending colon become fixed against the retroperitoneum during the normal course of fetal development. The greater and lesser omenta are also technically mesenteric in nature, and any consideration of tumors of these structures is generally inclusive of lesions of the greater and lesser omenta as well.

The vast majority of reported mesenteric tumors originate in the small-bowel mesentery or omentum. Mesenteric masses can arise as primary tumors, metastatic implants or lymph node involvement, or cellular proliferation secondary to infectious or inflammatory processes.

Pathophysiology

Clinical findings and symptoms associated with mesenteric tumors of all types are related to the presence of a mass lesion. Because the mass does not involve the tubular portion of the GI tract per se, obstructive symptoms are generally late findings in malignant mesenteric tumors and large benign tumors.

Without question, pain is the principal manifestation of mesenteric masses in adults and older children. A visceral pattern of pain may be related to mass effect within the peritoneum or to traction on the mesentery. This is generally deep and poorly localized discomfort, frequently described as central within the abdomen.

Benign mesenteric masses

These lesions are almost exclusively found in the mesentery of the small intestine, though cysts of the colonic mesentery have also been described. The incidence of cystic mesenteric masses in the United States is estimated at 1 per 100,000.[1] Most are lymphangiomas,[2, 3] but simple mesenteric cysts, enteric (duplication) cysts, pseudocysts, lipomas, and fibromas are also found, as well as rare benign mesenteric mesotheliomas with prominent cystic components.

Cystic lymphangiomas result from failed lymphatic channel development, resulting in lymphangiectasias and cysts. Patients are usually asymptomatic but can develop symptoms related to interval growth of the mass or as a result of complications (eg, rupture, superinfection, intracystic hemorrhage, or volvulus).[1] Cysts of the mesentery can become quite large before diagnosis (see the image below) and cause indolent symptoms that prompt workup and eventual treatment.

Massive mesenteric cyst that proved to be multiloc Massive mesenteric cyst that proved to be multiloculated lymphangioma. This large but benign structure had developed on narrow attachment to base of small-bowel mesentery and was amenable to excision without endangering any other mesenteric structures.

Other benign neoplasms of the mesentery are rare, but lipomas, neurogenic tumors, hamartomas,[4] and stromal tumors of small size with nonaggressive clinical behavior have been described. Actinomycosis and Whipple disease are infections that cause mesenteric masses from abscesses with granulation tissue and lymphadenopathy, respectively.[1]

Malignant mesenteric tumors

A relatively few tumor types account for the vast majority of mesenteric malignancies; in these malignancies, the small-bowel mesentery is almost exclusively the site of involvement.

Primary malignant mesenchymal or stromal tumors of the mesentery of the bowel (see the image below), as well as of the greater and lesser omenta, are a rare subset of abdominal cancers that resemble either retroperitoneal sarcomas or GI stromal tumors (GISTs) primary to the intestine.[5, 6, 7] In the past, many of these have been described as leiomyosarcomas.[8, 9]

Liposarcomas are locally aggressive malignancies with high risk of local recurrence after complete resection. Distant metastasis can occur in more poorly differentiated cancers of this type. Miettinen et al reported that in a group of 26 cases analyzed by the Armed Forces Institute of Pathology, the incidence of omental and mesenteric tumors was roughly equal.[10]

Characterization of protein markers of this tumor type has indicated that they are phenotypically very similar to the GIST group and are less often related to retroperitoneal stromal tumors. The absence of a detectable primary intestinal tumor signifies a primary mesenteric origin of the lesion.

Solitary fibrous peritoneal tumors have also been described, which may be benign or malignant. These much more commonly arise from pleural tissue in the chest, but mesentery is one of the described extrathoracic locations.[1] Extrathoracic locations have a higher incidence of malignancy, an increased recurrence rate after surgical resection, and the potential for distant metastasis.

Patients with mesenteric tumors can exhibit signs and symptoms of intestinal obstruction; however, in contrast to primary tumors of the intestine, much bulkier disease may be present before obstructive findings are encountered.

Desmoid tumors of mesentery

Mesenteric desmoid tumors are a relatively infrequent but potentially life-threatening complication of familial adenomatous polyposis (FAP).[11, 12] The incidence of desmoid tumors is 2.4-4.3 per 100,000 in the general population, whereas the frequency is in the range of 4-32% in patients with FAP.[1]  These tumors are areas of progressive fibroblastic and fibrous proliferation within the mesentery (and, less frequently, the retroperitoneum) that can locally involve vascular structures and can constrict and obstruct the bowel or the ureters. Although described as histologically benign, their infiltrative pattern of growth can ultimately lead to life-threatening patterns of visceral involvement.[13]

Sporadically occurring desmoid tumors are more numerous than those observed in FAP, though the cumulative risk of the development of these lesions is far greater in patients with FAP. Desmoid tumor is the second leading cause of death in patients with FAP. Sporadic mesenteric desmoid tumors are known to occur after trauma (eg, previous surgery), albeit rarely.[14, 15]

Although a causative relationship in desmoid formation has not been firmly established, various mutations of the APC gene have been identified in these tumors.[16] Desmoid tumors are more frequently associated with disease-causing mutations distal to codon 1444 of APC.

Mesothelioma

Although far less frequent than pleural disease, mesenteric mesothelioma related to visceral peritoneum has been reported in anecdotal cases for which surgical treatment of small-bowel obstruction was necessary.[17]

Mesenteric lymphoma

Lymphoma is the most common mesenteric malignancy, mostly consisting of non-Hodgkin lymphoma.[18] Primary mesenteric lymphoma, in contrast to primary small-bowel lymphoma, is a disease of the mesenteric lymph nodes that may represent a localized process or a component of a more disseminated pattern of disease. The clinical presentation of mesenteric lymphoma is much like that of other mesenteric tumors, with abdominal pain and palpable mass as the principal findings.

Computed tomography (CT) can characterize the lesion from the standpoint of size and mesenteric location and can raise the probability of the lymphoma diagnosis, though the finding of multiple enlarged lymph nodes raises other diagnostic possibilities. The typical CT image is of homogeneously enhancing lymphadenopathy (see the image below), generally adjacent to and sometimes encasing the mesenteric vessels with an intact perivascular border. The follicular centroblastic-centrocytic histologic type of lymphoma has been shown to predominate at mesenteric sites.[19]

Cluster of enlarged lymph nodes (arrows) in small- Cluster of enlarged lymph nodes (arrows) in small-bowel mesentery, which on laparoscopic biopsy proved to be B-cell (follicular) lymphoma.

The vast majority of metastatic lesions of the mesentery consist of mesenteric lymph nodes that have become secondarily involved in a neoplastic process of the GI tract. Distinguishing this pattern of tumor growth from primary mesenteric tumors usually presents no difficulty because the GI primary tumor site is generally identifiable.

Mesenteric carcinoid tumors

Carcinoid tumors of the small intestine are metastatic to mesenteric lymph nodes at the time of diagnosis in 40-50% of patients, though almost all such tumors that are greater than 2 cm in diameter have associated nodal involvement. Of these, a small subset may have minimal obvious disease within the small intestine and large mesenteric nodal metastases that may account for the vast majority of the tumor burden (see the image below). In addition, primary mesenteric carcinoids have been described that have been assumed to arise de novo in mesenteric tissues, though the veracity of this assumption is uncertain.

Mesenteric lymph node mass with metastatic involve Mesenteric lymph node mass with metastatic involvement of small-bowel carcinoid. This was resected en bloc along with segment of small bowel within arterial blood supply distribution affected by removal of mass. This small intestine contained subcentimeter primary carcinoid tumor.

Liver metastases may be present in patients with metastatic mesenteric carcinoid tumors. Nuclear medicine studies (including indium-111 pentetreotide or I-131 metaiodobenzylguanidine [MIBG]) can be used to confirm the diagnosis.[20] This pattern of disease may be accompanied by extrinsic compression and occlusion of the mesenteric arterial blood supply and segmental ischemia or infarction of the intestine. Extensive carcinoid tumor involvement of small-bowel mesentery has been reported in association with a malabsorption syndrome.

Sclerosing mesenteritis

Sclerosing mesenteritis is an umbrella term used to describe a rare idiopathic inflammatory and fibrotic disease of the mesentery. It is often described interchangeably as mesenteric lipodystrophy, mesenteric panniculitis, or retractile mesenteritis, though these terms could be used to describe a predominating histologic appearance corresponding to fat necrosis, inflammatory changes, or fibrotic features.[21, 1]

This condition can be mistaken for a mesenteric neoplasm on the basis of clinical, radiologic, and gross characteristics. It is a mesenteric thickening or mass that can be nodular in consistency and either focal or diffuse within the small-bowel mesentery. The root of the mesentery and the tissues surrounding the superior mesenteric vessels are commonly involved. CT or MRI may show the “fat ring sign,” denoting preservation of a fatty halo around the vessels (see the first image below), or “misty mesentery,” referring to hyperattenuation (see the second image below).[1]

Axial contrast-enhanced MRI of central hyperintens Axial contrast-enhanced MRI of central hyperintense fatty mesenteric mass with preservation of fat around vessels and lymph nodes with "fat ring" or “halo” sign (arrows) consistent with mesenteritis. Courtesy of BioMed Central Ltd, Springer Nature [Arda K, Kizilkanat KT, Aydin H. CT and MRI aspect of mesenteric panniculitis. J Case Rep Med 7. 2018 Jun 30.]
CT image of increased mesenteric tissue density or CT image of increased mesenteric tissue density or “misty mesentery” (between arrows), which laparoscopic incisional biopsy demonstrated was sclerosing mesenteritis.

The mass may consist of hypertrophied fatty tissue, dense fibrous tissue, fat necrosis, or combinations of these, along with a nonspecific chronic inflammatory infiltrate. Its presenting symptom is abdominal pain in most patients, though it has been anecdotally reported in association with fever, mesenteric calcifications, and protein-losing enteropathy.The cause of this condition is unknown, though associations with abdominal trauma, abdominal surgery, malignancy, and autoimmune diseases have been reported.

Treatment includes medical and surgical management, though the diagnosis is confirmed on operative biopsy. Other than a focal area of mesenteric thickening and induration, the affected tissues have no particular gross distinguishing features. Biopsy must be done with care to avoid mesenteric vascular injury. Because the problem most frequently involves more central areas of the mesentery, complete resection is not commonly possible. In patients with significant pain symptoms, there are options for medical management (see Medical Therapy). Rare cases of retractile mesenteritis with fibrosis that impairs intestinal perfusion have been reported, necessitating surgical resection for acute segmental ischemia. 

Mesenteric lymphadenopathy

Infectious etiologies of mesenteric lymph node enlargement include bacterial infection, mycobacterial infection, and histoplasmosis. A large number of these cases have been reported in conjunction with HIV infection. Although lymphadenopathy is usually generalized in tuberculosis, mesenteric lymphadenitis has been described as the principal presenting problem.

Castleman disease (giant lymph node hyperplasia) is a rare condition usually observed in the mediastinum. The even rarer cases in the abdomen are most frequently retroperitoneal, but cases of isolated mesenteric disease have been reported.[22] It can be classified as unicentric or multicentric.

The etiology of Castleman disease is not well known. In addition to HIV infection, it can be seen in association with herpesvirus 8, Kaposi sarcoma, Hodgkin disease, and non-Hodgkin disease.[1]  The estimated prevalence of Castleman disease ranges from 1 in 30,000 to 1 in 100,000 in the United States. The diagnosis is generally inferred from imaging studies and confirmed with histology. The differential diagnosis includes consideration of primary lymphoid neoplasms and metastatic lymph node involvement.[23]  Sarcoid has been reported as a cause of localized bulky mesenteric lymphadenopathy as well.

Etiology

No known etiologic or associated diseases have been reported in cases of primary mesenteric neoplasms. Reactive lymphadenopathy within the mesentery may be a manifestation of systemic, often infectious, disease.

Epidemiology

Solid primary tumors of the mesentery are rare. Published reports have consisted of small numbers of cases, which makes it difficult to determine the incidence of specific tumor types. Reasonable estimates of incidence have ranged from 1 case per 200,000 to 1 case per 350,000 population. Mesenteric tumors have been described as cystic in 40-60% of cases.[24]

Numerous anecdotal reports of mesenteric lipomas in adults and children have appeared over the years, suggesting that these probably represent the most frequently encountered symptom-causing solid tumors of primary mesenteric origin.

Malignant primary mesenteric tumors are extremely uncommon, even compared with primary malignancies of the small bowel. Published reports suggest that one third to one half of all mesenteric masses are malignant tumors. The largest case series have been from France and China.[25, 26]  Cook et al, using Surveillance, Epidemiology and End Results (SEER) program data, calculated male-to-female incidence rate ratios (IRRs) for various cancers for the period between 1975 and 2004.[27] According to their results, mesenteric cancer occurred more frequently in females than in males, with the overall male-to-female IRR for cancers of the peritoneum, omentum, and mesentery being 0.18.

Prognosis

The results of surgical treatment of benign cysts and solid tumors of the mesentery are very favorable. This is true of even large benign tumors, though local recurrence has been reported. Death as a consequence of benign masses, with the exception of mesenteric desmoid tumors, can be assumed to be an extremely unlikely event.

Because so few cases have been reported, long-term results of surgical treatment of malignant mesenteric mesenchymal tumors, which are histologically similar to GISTs, have not been well characterized. In fact, no large series reporting management and outcomes of treatment of this tumor type have been conducted. Published reports suggest that their biologic behavior is similar to that of primary GI mesenchymal malignancies.

A study of 114 mesenteric GISTs by Feng et al reported a 5-year disease-free survival rate of 57.7% and a 5-year disease-specific survival rate of 60.1%; these postoperative survival data were similar to those reported for intestinal GISTs.[28]  This uncontrolled comparison did not accurately account for the use of imatinib, which has proved very effective in the treatment of c-Kit-positive intestinal GISTs. Other specific postoperative adjuvant or palliative therapies, such as cytotoxic chemotherapy or radiation therapy, have not been shown to be of benefit.

Intra-abdominal desmoid tumors are the second most frequent cause of death in FAP patients (after cancer-related deaths).

 

Presentation

History and Physical Examination

Pain is the principal presenting symptom resulting in the discovery of a mesenteric mass. A palpable mass may also be present, though generally not without some abdominal pain. Nausea, vomiting, diarrhea, bloating, and constipation have also been described with mesenteric tumors.

Although most symptoms reflect a fairly indolent process, intestinal obstruction has been reported with benign and malignant mesenteric tumors. In the case of malignant tumors, this is generally secondary to aggressive local growth. In the case of benign tumors such as lipoma, the pathophysiology of obstruction is more complex.

Published descriptions of obstruction with mesenteric lipoma have implicated small-bowel encasement, small-bowel volvulus, or tumor infarction and obstruction due to the consequent inflammatory mass. Acute appendicitis as the result of torsion of a mesoappendiceal lipoma has also been described.

Clinical examination may reveal an abdominal mass. In the case of mesenteric lipoma, the tumor frequently cannot be appreciated by palpation. In the case of mesenteric cysts, physical examination findings may reveal a mass lesion that is mobile only from the patient's right to left or left to right (Tillaux sign), in contrast to the findings with omental cysts, which should be freely mobile in all directions.

 

Workup

Imaging Studies

Characterization of mesenteric tumors on the basis of imaging features can be accomplished by means of computed tomography (CT) and magnetic resonance imaging (MRI), which can provide important information regarding size, gross nature, and involvement of adjacent structures, as well as permitting inferences regarding the histopathologic nature of the tissue.[29, 30, 18, 20]  Localization of a mass to mesentery is generally possible in this way. CT and MRI can distinguish between solid and cystic masses and can identify metastatic disease in the abdomen or chest in advanced disease.

Abdominal computed tomography

Abdominal CT can be strongly suggestive of the diagnosis of lipoma as opposed to other solid tumors, though liposarcoma cannot be completely excluded on the basis of appearance on CT, particularly with very large lesions. Benign fatty tumors are usually homogeneous and have the density of normal mesenteric fat (see the image below). Lack of homogeneity or infiltrative processes that surround mesenteric vessels and lymph nodes should increase suspicion of malignant disease. To some extent, tumor vascularity can also be characterized with the administration of intravenous (IV) contrast during imaging.

CT image of benign mesenteric lipoma. This discret CT image of benign mesenteric lipoma. This discrete lesion (arrows) is homogeneous and has density of normal surrounding mesenteric fat.

Magnetic resonance imaging

MRI is sometimes used alone or in conjunction with other imaging methods to help characterize mesenteric masses. It provides information similar to that provided by CT but is better able to define tissue characteristics (eg, fatty vs fibrotic features) with high sensitivity. Direct comparisons of CT with MRI in the examination of mesenteric masses are lacking; however, MRI may be of great diagnostic value, particularly in patients with mesenchymal tumors. Diffusion-weighted sequencing, as compared with standard unenhanced MRI enterography, may improve visualization of mesenteric tissues and allow detection of both tumors and nonneoplastic masses.[31]

A study by Low et al found dynamic contrast-enhanced (DCE) MRI to yield better depiction of small-volume mesenteric tumors.[32] Ezhapilli et al described a systematic approach to characterization of mesenteric masses based on MRI characteristics that could provide a stepwise basis for defining possible diagnoses and aiding in the formulation of treatment plans.[20]

Arteriography

Arteriography is seldom used as a preoperative study in patients with mesenteric tumors unless there is a significant possibility that vascular involvement by the tumor may greatly complicate operative management. This procedure may define areas of mesenteric arterial blood supply that are compromised by tumor and may suggest the need for either extensive bowel resection with the mesenteric mass or arterial reconstruction.

Ultrasonography

The successful use of ultrasonography (US) to characterize mesenteric masses is well described, particularly as regards the ability of US to distinguish cystic from solid features. US is far less frequently employed for diagnostic characterization than CT and MRI, which provide significantly more anatomic information and are not as subject to operator-dependent technique and interpretation issues.

 

Treatment

Approach Considerations

The presence of any solid mass lesion of the mesentery that is not thought to be a reactive lymph node or lymphoma is an indication for surgical biopsy or excision, though observation and interval imaging have been advocated if there is a high suspicion of a mesenteric lipodystrophy diagnosis on the basis of computed tomography (CT) criteria.[33] The inability to exclude malignancy definitively for suspicious lesions makes prolonged observation and repetitive studies an ill-advised management strategy.

Image-guided core biopsy may be feasible and safe in appropriately selected cases. Otherwise, incisional biopsy is indicated to establish the diagnosis; this can frequently be accomplished laparoscopically. For example, lymphoma might represent a likely diagnosis on the basis of radiologic findings. If no other more readily accessible tissues were available, it would be necessary to obtain mesenteric tissue to guide therapy.

A small simple cyst of the mesentery discovered incidentally can be observed. In the setting of interval enlargement, significant symptoms (generally pain), or evolution of symptoms, surgical excision is advisable for simple cysts as well. A laparoscopic approach is frequently possible for this type of procedure (see the images below). Complex cystic structures related to the omentum must prompt consideration of the possibility of a neoplastic process.

Laparoscopic view of simple mesenteric cyst before Laparoscopic view of simple mesenteric cyst before laparoscopic excision.
Laparoscopic view of simple mesenteric cyst dissec Laparoscopic view of simple mesenteric cyst dissection bed after laparoscopic excision.

The use of laparoscopic methods to investigate and treat other mesenteric masses is an evolving area of surgical care. In patients whose disease must be distinguished from disease necessitating resection (eg, lymphoma or mesenteric lipodystrophy), laparoscopy offers a method of obtaining tissue for diagnostic purposes without subjecting the patient to a full laparotomy. At present, observation of good oncologic principles in approaching large lesions either known to be or suspected of being malignant requires laparotomy for proper local staging and operative planning.

Medical Therapy

Mesenteric masses and lymphadenopathy shown to be related to infection are best treated with appropriately directed antimicrobial therapy. Sclerosing mesenteritis has been treated with antimetabolites such as cyclophosphamide or azathioprine, which have been associated with a decrease in lesion size and with symptom relief. Other reportedly beneficial agents include corticosteroids, as well as colchicine, thalidomide, and tamoxifen alone or in combination with corticosteroids.[34, 35, 36]

The option of managing metastatic disease with palliative chemotherapy may be circumstantially necessary, with additional measures depending on response to treatment. Historically, chemotherapeutic regimens have not been effective for primary neoplastic mesenteric masses other than lymphoma. Pain and other gastrointestinal (GI) complaints can be treated with analgesics and antiemetics, but these agents do not address the underlying disease.

Targeted therapies have been investigated and encouraging results suggested for a variety of sarcoma types, including liposarcomas.[37, 38] Mesenteric soft-tissue sarcomas may generally be included in consideration of retroperitoneal sarcomas, and at present, it is not possible to cite specific results of targeted therapies for these.

Mesenteric lymphoma is treated with cytotoxic chemotherapy. Mesenteric desmoid tumors have been reported to respond to sulindac, hormonal manipulation, thalidomide, cytotoxic chemotherapy with doxorubicin-based combination regimens, and tyrosine kinase inhibitors, though results have generally been inconsistent or ultimately disappointing.[11, 39, 40] Radiation may be an option for unresectable, partially resectable, or recurrent mesenteric desmoid tumors—again, with inconsistent results. In a trial of the use of the protein kinase inhibitor sorafenib in patients with advanced desmoids, it was shown that the progression of disease could be slowed significantly.[41]

Surgical Therapy

In general, surgical treatment of benign mesenteric masses consists of local excision for smaller lesions. Most cystic mesenteric lesions can be easily excised. Resection of small intestine is rarely indicated for smaller benign tumors. One of the key goals of any operative approach is to preserve normal structures; however, resection can be quite treacherous, depending on the relation of the tumor to larger branches of the superior mesenteric artery. Surgical resection has the potential to be a major undertaking, with decision-making that involves consideration of en-bloc resection of visceral and vascular structures in order, ideally, to achieve negative surgical margins.

Approaches to different tumor types

Malignant mesenteric tumors

Surgical treatment is the therapy of greatest demonstrated benefit for these tumors. The goal of surgical treatment is removal of gross disease with tumor-free margins of resection. This can require en-bloc resection of any involved intestine, as well as any intestine that loses mesenteric arterial blood supply within the margins of resection needed to remove the tumor. As in the treatment of GI stromal tumors (GISTs) or retroperitoneal sarcomas, operative management may involve en-bloc resection of other involved structures. (See the images below.)

Mesenteric GIST-like tumor with solid and cystic c Mesenteric GIST-like tumor with solid and cystic components. Diagnosis was established after resection with demonstration of absence of primary GI tumor.
Resected mesenteric tumor. Operative treatment inv Resected mesenteric tumor. Operative treatment involved segmental small-bowel and colon resection. Large specimen size is evident.

Mesenteric desmoid tumors

These are very difficult lesions to treat surgically. Surgical treatment may increase recurrence risk, because it has been observed that desmoid tumors generally occur after abdominal surgery. Surgical debulking may be dangerous and ultimately unsuccessful and is generally reserved for patients with intestinal obstruction.[11, 12]  There is some suggestion that multimodality treatment with with liposomal doxorubicin may be followed by a response sufficient to make previously unresectable disease resectable.[42]

Mesenteric lymphoma

In contrast to primary small-bowel lymphoma, for which surgical treatment may play a valuable role in selected cases, mesenteric lymphoma is best treated with combination chemotherapy. Although some cases are diagnosed after resection of an uncharacterized mesenteric mass, surgical treatment is best used as a diagnostic tool when the diagnosis is probable but uncertain. Laparoscopy may play an important role when procurement of tissue for diagnostic purposes is the operative goal.

Mesenteric carcinoid tumor

This pattern of disease is treated by surgically resecting the mesenteric masses. This procedure should be performed en bloc with any extant primary intestinal tumor. Resection of mesenteric disease should be accomplished without endangering the blood supply to normal bowel, except in the immediate area of the disease. A primary carcinoid tumor, which may be quite small and multicentric, is generally found in the resected intestinal specimen.

Castleman disease

Because this problem is nonneoplastic and can be localized, treatment should consist of local resection of the lymph node mass, which has had good reported results. Successful treatment using a laparoscopic approach has also been reported.[43]

Operative details

At exploration, initial steps generally involve characterization of disease on the basis of local and regional considerations, as well as pathology distant from the mesenteric mass. Masses may be completely contained within the mesentery, demarcated from surrounding tissues, or difficult to distinguish from normal surrounding mesenteric tissues. In the case of locally aggressive malignant masses such as liposarcoma, encasement of vascular structures or bowel with tumor tissue can occur (see the image below).

Section of malignant mesenteric fatty tumor resect Section of malignant mesenteric fatty tumor resected en bloc with obstructed, encased small intestine.

The gross extent of the tumor must be carefully defined in order to identify clear margins of resection, which should be the goal of extirpative treatment. Definition of proximity to large mesenteric blood vessels is vital. Normal intestine should be preserved to the greatest extent possible while good oncologic surgical principles are still observed in defining bowel segments for resection. If resection requires removal of so much intestine that maintenance of nutrition cannot be expected, the patient's clinical situation (eg, age and general health) must be considered before the resection is undertaken.

Complications

Complications of surgical treatment of mesenteric masses are not specific to the disease type, except when extensive resection of solid tumors may endanger the mesenteric blood supply or when extensive small-bowel resection is necessary to remove the disease. Although short-gut syndrome is an infrequent occurrence in surgery involving the mesentery, appropriate precautions must be taken to prevent this condition, which can result from excessive resection or from inadvertent damage to the blood supply of otherwise unaffected bowel.[1]

The difficulties associated with desmoid tumors for which surgery is undertaken raise particular concerns for complications such as bleeding and injury to involved or neighboring structures.