Benign pancreatic tumours

Benign pancreatic tumours comprise a heterogeneous group of neoplastic lesions characterised by the absence of local invasiveness and distant metastasis, with generally indolent biological behaviour. Although they represent a minority compared with malignant pancreatic neoplasms, these lesions are clinically relevant because of the complexity of differential diagnosis, the need to distinguish truly benign forms accurately from lesions with low malignant potential, and the management implications of their anatomical location and the potential morbidity of pancreatic surgery.

Histologically, benign pancreatic tumours include mainly serous cystic neoplasms, traditionally regarded as benign, together with rare mesenchymal lesions such as lipomas, schwannomas and hamartomas. A substantial proportion of these lesions is clinically silent and is identified incidentally during radiological investigations performed for other reasons. In a minority of cases, especially when size increases or location causes compression of adjacent structures, symptoms related to mass effect, ductal obstruction or digestive disturbance may occur.

Diagnosis of benign pancreatic tumours requires rigorous assessment aimed at confirming their indolent nature and excluding malignant neoplasms or precursors with a risk of progression. The pathway integrates high-resolution morphological imaging, magnetic resonance characterisation and, in selected cases, endoscopic ultrasound assessment with tissue sampling. Management is typically multidisciplinary and aims to balance diagnostic and clinical safety against the need to avoid unnecessary resections, given that pancreatic surgery may carry significant complications even when appropriately indicated.

The epidemiology of benign pancreatic tumours is difficult to quantify because many lesions remain asymptomatic and are diagnosed only after imaging performed for non-pancreatic indications. Over recent decades, the apparent frequency of incidental pancreatic findings has risen substantially in parallel with the widespread availability and increasing use of high-resolution CT and MRI. In this setting, some identified lesions have features compatible with benign behaviour, although reliable distinction requires integrated assessment and sometimes longitudinal follow-up.

Among the most clinically representative entities are serous cystic neoplasms, which account for a substantial proportion of pancreatic cystic neoplasms with indolent behaviour. These lesions are more often described in adults, with distributions varying according to case series and diagnostic criteria. Diagnosis is incidental in many patients; when symptoms occur, they are usually related to large size and compression of adjacent structures rather than aggressive biological behaviour.

Benign mesenchymal lesions of the pancreas, including lipomas, schwannomas and hamartomas, are very rare and their epidemiology is derived mainly from case reports and small series. Age at diagnosis varies, and the absence of specific signs often leads to incidental identification or inconclusive radiological suspicion. Because of their rarity, much clinical attention focuses on differentiating them from more common and clinically important solid pancreatic tumours.

Specific risk factors for benign pancreatic tumours are generally poorly defined and, unlike ductal adenocarcinoma, there is no consistent, reproducible association with smoking or alcohol. Some lesions, particularly certain cystic forms and syndromic conditions, have been associated with genetic disorders and alterations in cellular pathways controlling growth and differentiation, but overall clinical risk remains distinct from that of conventional malignant neoplasms. In practice, the central determinant of management is not identification of a causal risk factor but correct interpretation of the radiological finding and its stability over time.

Overall, epidemiological evidence suggests that benign pancreatic tumours constitute a relatively rare but increasingly recognised category because of diagnostic imaging. The decisive clinical issue is correct attribution of the lesion to an indolent phenotype, avoiding overtreatment and establishing follow-up proportionate to the risk profile.

There are no population screening programmes for benign pancreatic tumours. Their relative rarity, the lack of demonstrated benefit from systematic detection and the risk of overdiagnosis make mass screening inappropriate. In clinical practice, diagnosis occurs mainly incidentally during radiological examinations performed for other reasons or during diagnostic work-up initiated for non-specific symptoms.

Surveillance is a cornerstone of management for many pancreatic lesions with indolent behaviour, particularly cystic neoplasms whose radiological features are compatible with a low-risk phenotype. Follow-up aims to document dimensional and morphological stability over time, recognise any evidence of evolution early and reconsider the diagnostic hypothesis when behaviour is inconsistent with presumed benignity. The frequency of examinations is determined according to size, imaging features, symptoms and the overall clinical context.

Reference surveillance methods include magnetic resonance imaging, often combined with MR cholangiopancreatography for better ductal characterisation, and contrast-enhanced CT when useful for evaluating vascular relationships and characterising solid components or calcifications. Endoscopic ultrasonography has a selective role, especially when cross-sectional imaging does not permit reliable classification or when high-resolution assessment of the cyst wall or intracavitary components is required.

In individuals with inherited predispositions and specific clinical settings in which pancreatic surveillance is already structured, apparently indolent findings may also be monitored more closely because the overall risk of pancreatic disease does not depend solely on the individual lesion. In these cases, the strategy is personalised and defined within a multidisciplinary setting, avoiding automatic decisions and maintaining focus on consistency among the finding, clinical history and evolutionary trajectory.

In summary, the most rational approach is targeted, proportionate surveillance aimed at ensuring clinical safety while minimising invasive procedures and unjustified resections in the presence of lesions with indolent behaviour.

Benign pancreatic tumours include lesions arising from the pancreatic exocrine compartment and stroma, characterised by predominantly expansile growth, absence of destructive infiltration of anatomical planes and absence of metastasis. Their clinical relevance derives mainly from the difficulty of differential diagnosis with more common entities and from their potential to cause compressive symptoms or local complications, rather than from an intrinsic oncological risk.

Biologically, truly benign lesions share a low proliferative index, orderly tissue architecture and preservation of relatively conserved differentiation programmes. In serous cystic neoplasms, indolent behaviour is consistent with slow growth and an often stable natural history, in which the development of symptoms tends to correlate with size and mass effect. In benign stromal lesions, expansion is generally well circumscribed and symptoms, when present, are related more to location and size than to aggressive features.

At the molecular level, many benign lesions show high genomic stability and a biological profile consistent with non-infiltrative behaviour. In clinicopathological practice, it is essential to distinguish truly benign entities from rare pancreatic neoplasms classified as having low malignant potential or uncertain potential, which may share radiological or morphological features with indolent lesions but require a different approach. This conceptual boundary is particularly important because the term “benign” in the pancreas has direct implications for the choice between surveillance and surgery.

Histologically, serous cystic neoplasms are characterised by small cystic cavities lined by glycogen-rich cuboidal epithelium, with absent or minimal atypia and a characteristic architectural pattern. Pancreatic lipomas consist of well-circumscribed mature adipose tissue, whereas schwannomas show proliferation of spindle cells with features typical of nerve-sheath tumours and variable patterns that may complicate radiological diagnosis. Pancreatic hamartomas, which are exceptional, are disorganised lesions composed of mature elements and are not strictly neoplastic, with an often non-specific clinical and radiological presentation.

Immunohistochemistry supports definition of the line of differentiation and the differential diagnosis: epithelial markers in cystic lesions, nerve-sheath markers in schwannomas and a low Ki-67 proliferative index are consistent with indolent behaviour. The absence of lymphovascular and perineural invasion and the lack of significant tumour necrosis provide additional morphological support for a benign interpretation when sampling is adequate.

The principal types included in this category are:

Examples of benign tumours and indolent neoplastic lesions of the pancreas

• serous cystic neoplasms, often microcystic and slow-growing;
• lipomas, rare lesions composed of mature adipose tissue;
• schwannomas, generally well-circumscribed nerve-sheath tumours;
• pancreatic hamartomas, exceptional lesions that are often difficult to diagnose.

Overall, biology and histology explain why these lesions generally have a favourable prognosis and why management should focus on correct classification and prevention of overtreatment while maintaining an adequate level of diagnostic safety.

Clinical manifestations of benign pancreatic tumours are frequently absent because of their slow growth and lack of invasiveness. A substantial proportion of patients are diagnosed incidentally during imaging performed for non-pancreatic indications. In these situations, the main clinical issue is not symptom management but accurate definition of the lesion’s nature and risk profile.

When present, symptoms are mostly related to mass effect or compression of adjacent structures. Abdominal pain, often vague and intermittent, may be located in the epigastrium or upper quadrants and reflect capsular distension, traction on peripancreatic tissues or compression of neighbouring organs. Large lesions may cause early satiety, nausea and postprandial heaviness due to gastric or duodenal compression.

Location in the pancreatic head may cause compression of the bile ducts or duodenum, leading to obstructive jaundice or dyspeptic symptoms. Although possible, these presentations always require cautious evaluation because the differential diagnosis includes more common malignant entities. In the body and tail, symptoms tend to be even more subtle and often occur late, with incidental detection remaining the predominant mode of presentation.

In some circumstances, particularly when a lesion interferes with the pancreatic duct or ductal physiology, episodes of pancreatitis or recurrent pancreatic pain may occur. This requires structured reassessment of the finding and its relationship with the ductal system. Physical examination is often non-contributory; a palpable mass is rare and is typically associated with very large lesions or particular body habitus.

Presentation may be summarised as follows:

Common clinical presentations according to size and location

• small lesions: often asymptomatic and detected incidentally;
• large lesions: pain, early satiety, nausea and compressive symptoms;
• lesions in the pancreatic head: possible jaundice or duodenal symptoms, requiring rigorous differential diagnosis.

Overall, the clinical picture of benign pancreatic tumours is dominated by non-specificity and slow progression. Management depends more on correct classification of the finding and assessment of overall risk than on symptom intensity, with a generally excellent prognosis when the lesion is correctly identified and monitored.

The diagnostic pathway for benign pancreatic tumours often begins with an incidental imaging finding. The objective is to recognise an indolent lesion profile, reliably distinguish truly benign forms from malignant neoplasms and lesions with potential for progression, and accurately define size, anatomical relationships and behaviour over time. Because the pancreas may also harbour rare low-grade neoplasms and cystic lesions with variable risk, diagnosis cannot be based on a single finding but requires integration of clinical information, imaging and, when necessary, histology.

Clinical assessment includes a history directed toward compressive symptoms, episodes of pancreatitis, jaundice, unintentional weight change and a family history of pancreatic disease, while physical examination is often minimally informative. Laboratory tests have a limited role: serum tumour markers, including CA 19-9, may be normal even in clinically relevant disease and do not provide a reliable discriminatory criterion. Biochemical abnormalities may occur mainly when biliary compression or associated pancreatic injury is present.

Imaging is the cornerstone of assessment. Contrast-enhanced CT defines size, margins, enhancement pattern and relationships with vessels and ducts, identifying features suggestive of benignity such as expansile growth, well-defined margins and absence of vascular invasion. MRI provides more detailed tissue characterisation, helping recognise patterns typical of some indolent lesions, assess cystic components and ductal relationships, and improve risk stratification of incidental findings.

Endoscopic ultrasonography (EUS) is indicated when CT and MRI do not permit reliable classification or when radiological findings and the clinical context are discordant. EUS provides high-resolution assessment of the lesion and surrounding parenchyma and, in selected cases, permits sampling by fine-needle aspiration or core-needle biopsy. Sampling is particularly useful when the differential diagnosis includes solid pancreatic tumours or cystic neoplasms with risk features, but it must always be considered within a risk–benefit assessment because procedural complications, although uncommon, are possible.

When tissue is obtained, pathological examination permits definitive characterisation of the lesion. Benign tumours generally show orderly architecture, absence of significant atypia, low mitotic activity and no stromal invasion. Immunohistochemistry contributes to differential diagnosis by confirming the line of differentiation and supporting an interpretation of indolent behaviour in the presence of a low Ki-67 index and immunophenotypic profiles consistent with the suspected entity.

In practice, reliable assessment integrates several recurrent elements:

Clinical and imaging features suggesting a benign profile

• Radiological features compatible with an indolent lesion and no evidence of invasiveness.
• No rapidly progressive clinical manifestations and no unexplained ductal obstruction.
• Characterisation with CT and MRI, including assessment of vascular and ductal relationships.
• Use of EUS and sampling when the differential diagnosis remains clinically relevant.
• Multidisciplinary discussion to define surveillance or a proportionate surgical indication.

The differential diagnosis includes ductal adenocarcinoma, neuroendocrine tumours, cystic neoplasms with potential for progression and rare low-grade neoplasms. For this reason, the diagnostic pathway must avoid both underestimation and excessive intervention. Once a lesion has been assigned with reasonable confidence to a benign profile, the most common approach is structured surveillance, with reassessment if significant dimensional or morphological changes occur.

Oncological staging does not apply to benign pancreatic tumours because these lesions are, by definition, devoid of metastatic capacity and the infiltrative behaviour typical of malignant neoplasms. The clinically useful concept is assessment of local extent and clinical risk, understood as the probability of symptoms, compressive complications, persistent diagnostic difficulty and the need for intervention over time.

Prognosis is generally excellent. In most cases, the lesion remains confined to the pancreas and can be followed by surveillance without affecting survival. Possible clinical evolution is more often related to growth and location, with the development of compressive symptoms or pancreatitis, than to malignant transformation. For serous cystic neoplasms, many series describe an indolent trajectory with slow enlargement and a need for treatment mainly when the lesion becomes symptomatic or when differentiation from non-benign forms cannot be achieved with sufficient confidence.

In practical terms, the most common clinical and prognostic scenarios include:

Clinical scenarios and prognosis in benign pancreatic tumours

• Asymptomatic, stable lesions: excellent prognosis with surveillance and progressively longer intervals between examinations when stability is confirmed.
• Symptomatic lesions: possible indication for treatment, with resolution of the clinical picture in most cases.
• Lesions with growth or persistent diagnostic uncertainty: multidisciplinary reassessment and possible selective surgery, with prognosis determined mainly by procedural morbidity.

When a truly benign lesion is completely resected, the oncological outcome is generally curative and recurrence is exceptional. The principal determinants of outcome are complications of pancreatic surgery and functional sequelae rather than lesion biology. Prognostic assessment must therefore explicitly balance biological indolence against procedural risk, avoiding an automatic progression from the label “tumour” to disproportionate treatment.

Treatment of benign pancreatic tumours is based on a conservative and selective approach guided by location, size, symptoms, evolutionary trajectory and diagnostic certainty. The therapeutic decision should be made in a multidisciplinary setting because the objective is not simply to remove the lesion, but to avoid unnecessary resections in an organ in which surgery can carry substantial morbidity.

In many patients, the initial strategy is clinical and radiological surveillance, especially when the lesion is small, asymptomatic and has imaging features consistent with indolent behaviour. This approach documents stability and reduces exposure to invasive procedures. Conservative management is particularly rational when the finding is compatible with an uncomplicated serous cystic neoplasm or a well-circumscribed stromal lesion without evidence of aggressiveness.

Surgical treatment is reserved for selected situations, including symptoms attributable to the lesion, such as persistent pain, jaundice due to biliary compression or recurrent episodes of pancreatitis caused by ductal interference. Another important indication is progressive growth or persistent diagnostic uncertainty, when a different biological nature cannot be reasonably excluded after complete imaging and possible EUS assessment and when the clinical consequences of diagnostic error would be substantial.

The choice of operation depends on location. In selected cases involving well-circumscribed lesions, enucleation may be considered to preserve pancreatic parenchyma. Lesions in critical locations or with complex relationships to the main pancreatic duct may require anatomical resections, such as distal pancreatectomy for lesions of the body and tail or, more rarely, resection of the pancreatic head when the lesion is closely related to the bile ducts or duodenum. In every scenario, planning should maximise procedural safety and minimise the risk of functional sequelae.

Risk–benefit assessment is central. Pancreatic surgery may cause pancreatic fistula, infection, haemorrhage, delayed gastric emptying and late sequelae such as exocrine and endocrine insufficiency. Resection of a presumably benign lesion therefore requires a sound clinical rationale related to symptoms, complications, growth or clinically significant diagnostic uncertainty.

In patients who have undergone surgery, perioperative management and nutritional support are integral to treatment. Prevention and early recognition of exocrine pancreatic insufficiency and glycaemic abnormalities improve outcomes and reduce the impact on quality of life, ensuring comprehensive care even for biologically indolent disease.

Follow-up of benign pancreatic tumours aims to monitor stability over time in lesions managed by surveillance and to identify sequelae and complications early in patients who have undergone resection. Management is individualised and depends on lesion type, location, size, the quality of diagnostic characterisation and the patient’s clinical profile.

In patients undergoing active observation, surveillance is primarily radiological. MRI and, in selected cases, CT document size and morphology and detect changes suggesting a shift in biological trajectory or an error in the initial classification. When repeated stability is documented, the intervals between assessments may be progressively lengthened, while retaining the option to bring examinations forward if new symptoms or clinical changes occur.

During follow-up, attention is also directed toward persistent pain, episodes of pancreatitis, signs of biliary or ductal obstruction and changes in nutritional status. These findings may require repeat imaging, use of EUS or multidisciplinary reconsideration of the surgical indication, particularly when the lesion grows or differentiation from non-benign entities again becomes clinically relevant.

In patients who have undergone resection, follow-up includes assessment of functional sequelae. Monitoring for exocrine pancreatic insufficiency, glycaemic abnormalities and digestive disorders is essential, with nutritional supplementation and enzyme therapy when indicated. Postoperative imaging is used selectively, particularly during the early period, and subsequently according to symptoms, complications or specific clinical needs.

Follow-up is generally longer when the initial diagnosis is probabilistic and the lesion has been managed without definitive histology, whereas it may be shorter after complete resection with confirmation of benignity and no complications. In every case, follow-up should protect quality of life and reduce unnecessary healthcare burden, consistently with the biological indolence of most of these lesions.

Long-term quality-of-life considerations are clinically relevant in benign pancreatic tumours despite the absence of malignant behaviour, because diagnosis, surveillance and any treatment may substantially affect daily life. In many cases the lesion is discovered incidentally, but the label of pancreatic disease can create a persistent psychological burden, especially when follow-up is prolonged and involves repeated radiological examinations.

An important domain is the burden of surveillance. Waiting for examinations, interpreting minimal changes and living with uncertainty may cause anxiety and stress even when biological risk is low. Clear communication explaining the probability of an indolent course and the rationale for surveillance reduces psychological impact and improves adherence to proportionate follow-up, avoiding both unnecessarily frequent examinations and inappropriate discontinuation.

In patients who undergo surgery, quality of life often depends more on functional sequelae than on the lesion itself. Exocrine pancreatic insufficiency may present with diarrhoea, steatorrhoea, bloating and weight loss, requiring enzyme-replacement therapy and lasting dietary adjustments. The development of glycaemic abnormalities or pancreatogenic diabetes may require continuous monitoring and lifestyle changes, affecting perceived health and independence.

The nutritional dimension is central. After pancreatic resection, even for benign disease, nutritional vulnerability may persist, with loss of muscle mass and fatigue. Structured nutritional support, combined with adapted physical activity when possible, promotes functional recovery and reduces the impact on daily life.

Pain and chronic abdominal symptoms, when present, may interfere with rest and work. Even low-intensity persistent pain can reduce perceived well-being and encourage avoidance of physical or social activities. An integrated approach, with proctological and gastroenterological assessment when necessary, optimises symptom control and reduces repeated, unhelpful interventions.

Overall, long-term quality of life depends on the care pathway’s ability to ensure integrated management in which rational surveillance, nutritional and metabolic management, and psychological support are proportionate to the actual risk. This keeps management of benign pancreatic tumours consistent with their biological indolence and focused on the patient’s overall well-being.

Complications of benign pancreatic tumours arise from the interaction between anatomical location, lesion size, evolutionary trajectory and diagnostic or therapeutic strategies. Even with indolent biological behaviour, clinically relevant functional complications may occur, especially when the lesion grows, compresses adjacent structures or is treated surgically.

The first category consists of complications from mass effect. Large lesions may compress the duodenum, stomach or bile ducts, causing nausea, early satiety, pain and, in some cases, obstructive jaundice. Compression of the pancreatic duct may promote episodes of pancreatitis or recurrent pancreatic pain, with a potential progressive effect on exocrine and endocrine function. In these scenarios, the complication is related not to metastasis but to the anatomical relationship between the lesion and ductal or vascular structures.

A second category concerns diagnostic complexity. Uncertainty in the differential diagnosis may lead to repeated invasive procedures, excessively frequent follow-up or, conversely, delayed recognition of non-benign entities. The need for diagnostic safety must be balanced against the risk of overusing procedures, maintaining a proportionate, multidisciplinary approach.

A clinically important issue is the risk of overtreatment. Resection of an indolent lesion may expose the patient to substantial morbidity without proportional benefit, particularly when the indication is based on uncertainty that has not been addressed through an adequate diagnostic pathway. Careful selection of surgical candidates is therefore a fundamental preventive measure.

When pancreatic surgery is performed, perioperative complications may be important. Postoperative pancreatic fistula, intra-abdominal infection, haemorrhage and delayed gastric emptying are recognised events that affect hospital stay and recovery. In the longer term, exocrine and endocrine pancreatic insufficiency are clinically relevant sequelae with consequences for nutrition, metabolism and quality of life. Invasive diagnostic procedures such as EUS-guided sampling also carry a small but real risk of pancreatitis, bleeding or infection that must always be considered in the risk–benefit assessment.

Management of complications is based on prevention and early recognition. Appropriate selection for surveillance or treatment, the use of suitable surgical techniques in expert centres and follow-up focused on functional sequelae and nutritional status reduce morbidity and preserve quality of life, keeping the entire pathway consistent with the biological indolence of most benign pancreatic tumours.