Where it is available, ERCP with endoscopic sphincterotomy and endoscopic stone extraction is the most common treatment for common bile duct stones that do not pass spontaneously (Fig 26.3). If ERCP is not available the duct is usually cleared by laparoscopic or open surgery. If the gallbladder is still present it is usually removed at the same operation. Thus, if ERCP is not readily available or, in patients not needing urgent clearance of the bile duct, a two-stage treatment (ERCP and subsequent surgical removal of the gallbladder) can on occasion be condensed into a single phase treatment by omitting the ERCP and utilising a single surgical procedure to remove the gallbladder and clear the bile duct, usually laparoscopically.

Figure 26.3 ERCP demonstrating stones in the bile duct. These had been difficult to see on ultrasound scan due to overlying bowel gas.

Choledochal cysts

Choledochal cysts are most commonly congenital and most commonly present with cholestasis during infancy. However, 20% present in adulthood, frequently as incidental scan findings in individuals with no biliary symptoms. Women are more commonly affected than men (80%; 4:1 female/male ratio). The development of some choledochal cysts may be explained by anomalous union of the common bile duct and pancreatic duct during embryogenesis. The resulting anatomy allows mixing of pancreatic juice and bile within the bile ducts. Exposure of the pancreatic exocrine proenzymes to bile activates the pancreatic digestive enzymes within the bile ducts, perhaps in turn leading to weakening and dilation of the duct and inducing epithelial changes predisposing to bile duct cancer (cholangiocarcinoma).

Choledochal cysts may occur anywhere in the biliary tree. They may be focal or diffuse, single or multiple. They are classified on the number of cysts present and on their position in the intra- or extrahepatic biliary tree (Table 26.1). Though not primarily caused by bile duct obstruction or by strictures, tumours or stones, all these problems may develop in association with them and may in turn lead to complications such as cholestasis (obstructive jaundice), infection in the biliary tree (cholangitis), impaired hepatic function (liver failure), hepatocellular loss and hepatic fibrosis (cirrhosis) and bile duct cancer (cholangiocarcinoma).

Table 26.1 Todani classification of choledochal cysts

Site of cyst	Classification	ERCP findings
Extrahepatic	I	Solitary fusiform cyst
	II	Supraduodenal diverticulum
	III	Intraduodenal diverticulum (choledochocoele)
	IVB	Multiple extrahepatic cysts
Extrahepatic and intrahepatic	IVA	Extra and intrahepatic cysts
Intrahepatic	V	Multiple intrahepatic cysts (Caroli’s disease)

ERCP = endoscopic retrograde cholangiopancreatography.

The discovery of intrahepatic or extrahepatic bile duct dilation consistent with choledochal cysts necessitates further investigation, initially by assessment of liver function and by MRCP or CT cholangiography. Masses associated with choledochal cysts anywhere in the biliary tree may be due to cholangiocarcinoma and should be assumed to be so until proven otherwise.

Extrahepatic choledochal cysts usually require excision of the extrahepatic ducts and reconstruction for biliary drainage with a choledochoenterostomy (anastomosis of the end of the remaining bile ducts to a loop of jejunum). Multiple intrahepatic cysts may not be amenable to surgery and are usually treated with endoscopic or percutaneous tubes (stents) in the bile ducts if biliary drainage is impaired. In such cases the cycle of chronic biliary obstruction and recurrent biliary sepsis may lead to liver failure and necessitate hepatic transplantation.

Pancreatic Incidentalomas

Unexpected imaging detected masses in the pancreas may be cystic or solid and may be derived from stromal, exocrine or endocrine elements of the pancreas. Lymph glands lying in or adjacent to the pancreas may also be responsible for incidentally detected asymptomatic pancreatic masses. As with incidentalomas elsewhere, the first step in non-invasive investigation of pancreatic incidentalomas is always to revisit the clinical history and examination. A past history of epigastric pain may correspond to a previous episode of pancreatitis. Epigastric pain associated with back pain may be consistent with pancreatic cancer, as would a history of nausea or weight loss. A palpable epigastric mass is possible and should be looked for but is unlikely unless a pancreatic lesion is very large. An enlarged supraclavicular lymph node, an umbilical nodule or a hepatic mass may betray previously unsuspected metastatic disease.

Managing pancreatic masses usually requires referral to a specialist multidisciplinary pancreatic unit. The first step in non-invasive imaging of unexpected pancreatic masses is to differentiate cystic from solid. This is most simply done with ultrasound scanning. However, CT and MRI scans are often needed, especially if a mixed cystic and solid mass is suspected. If invasive investigations are indicated, endoscopic ultrasound scanning is very useful to differentiate a simple cyst from a complex cyst and to achieve cyst fluid aspiration for cytology, biochemistry and tumour marker levels or to achieve a tissue diagnosis by fine needle aspiration biopsy and cytology.

Focal pancreatitis

Focal pancreatitis can result in incidentally detected solid pancreatic masses which on closer investigation are often associated with previous symptoms that were not recognised as caused by pancreatitis. Some of these focal pancreatitis lesions will settle during investigation but they may persist for a long time and their true nature can be very difficult to sort out. Endoscopic ultrasound scanning and needle aspiration cytology may resolve the issue. Rarely, autoimmune pancreatitis will present clinically as a focal pancreatic mass in which case serum IgG4 levels may be elevated. Pancreatic resection may be considered on a working diagnosis of pancreatic cancer. But surgery for focal pancreatitis of any sort should be avoided and pancreatic cancer should, if possible, be excluded non-surgically. The services of a specialised multidisciplinary pancreatic service should be enlisted.

Pancreatic cysts

Most asymptomatic cystic lesions of the pancreas are simple cysts. Simple cysts of the pancreas are usually unilocular, lined by simple one-layered epithelium and contain serous fluid. They do not enlarge and do not become malignant or cause complications and they require no treatment. The difficulty is establishing a firm diagnosis of simple cyst while excluding the possibility of a cystic neoplasm or a pseudocyst. Endoscopic ultrasound scanning may provide more detailed images and facilitate needle aspiration of the cyst fluid. Simple cysts will contain fluid with cytologically benign cells and low levels of carcinoembryonic antigen and CA 19-9. Mucinous cystadenoma fluid may show cytologically atypical cells and elevated tumour marker levels. Amylase and lipase levels will be high in fluid from pancreatic pseudocysts, but they have no epithelial lining so no epithelial cells should be seen on cytology from pancreatic pseudocyst fluid.

Most incidentally detected pancreatic pseudocysts are small (less than 5 cm) and uncomplicated. These usually resolve and, although continued observation with follow-up scans may be warranted until resolution is demonstrated, very few require any intervention. Large pseudocysts are rarely incidental findings. Spontaneous resolution becomes less reliable as pseudocysts become larger than 5 cm and is unlikely to occur for pseudocysts over 10 cm. Accordingly, larger pseudocysts will usually require drainage. Endoscopic, percutaneous and laparoscopic or open surgical techniques can be used for this. Selection of a pseudocyst drainage technique should be individualised for each case and specialist advice should always be sought.

Hydatid disease can involve the pancreas and cause cysts just as it does in the liver. Hydatid disease in the pancreas is a marker of disease dissemination and while it may be an unexpected finding in the context of a particular case of hydatid disease, it is rarely a truly incidental finding. The radiological features are curved plates of calcification in cyst walls and grape-like daughter cysts within large cysts.

Cystic neoplasms of the pancreas

These are usually multilocular and commonly have solid elements or irregular thickening of their walls. They are often asymptomatic and so are liable to present as incidental imaging findings. The most common pancreatic cystic neoplasms are serous cystadenoma and mucinous cystadenoma. Less common mixed solid and cystic pancreatic neoplasms include microcystic adenomas and papillary and cystic tumours (Ch 17). Though it may be difficult, distinguishing between these neoplastic lesions is important as they have quite different malignancy risks. If a lesion can be demonstrated to be a serous cystadenoma by detection of tiny flecks of calcium in the cysts wall on CT or MRI scanning and on endoscopic ultrasound suggestive cytology features and elevated cyst fluid tumour marker levels, then no treatment is required as pancreatic serous cystadenomas are benign with no malignant potential. Conversely, if the lesion is a mucinous cystadenoma and the patient is fit, resection should be considered as some of these are malignant (cystadenocarcinoma) even though they may look histologically benign on biopsy. Pancreatic cystadenocarcinoma carries a much higher chance of cure than does the more common pancreatic adenocarcinoma, especially if detected early and resected completely (see Ch 17).

Pancreatic adenocarcinoma

By far the most common malignant pancreatic neoplasms are adenocarcinomas derived from the exocrine pancreas. They can occur anywhere in the pancreas, but those that develop in the head of the gland are rarely detected at an asymptomatic stage as they tend to involve the bile duct and cause obstructive jaundice. Cancers of the body and tail of the pancreas are well away from the bile duct and are more likely to be detected incidentally on abdominal scans where they are usually seen as solid or mixed cystic and solid masses.

It can sometimes be difficult to differentiate pancreatic cancer from lymphoma, focal pancreatitis or rarely, focal autoimmune pancreatitis. Lymphoma can usually be identified on a biopsy and autoimmune pancreatitis by presence of elevated serum IgG4 levels. Focal pancreatitis may resolve during investigation or observation, but can persist for quite long periods and can result in misguided resection for what was thought to be pancreatic cancer. Lymphoma and autoimmune pancreatitis are treated by non-surgical means. If possible, pancreatic masses should be biopsied by endoscopic or endoscopic ultrasound scanning guided routes if there is any diagnostic doubt.

Cure rates for pancreatic adenocarcinoma are dismal, but perhaps the best chance of cure will be for the occasional small, asymptomatic, incidentally detected case. All such cases should be referred promptly for specialist evaluation. Most will require some form of invasive investigation to secure the diagnosis, most commonly endoscopic ultrasound scanning and ERCP. Those that are malignant will also require staging investigations before pancreatic resection is considered (see Ch 17).

Endocrine pancreatic neoplasms

Endocrine neoplasms of the pancreas may be functional (secretory) or non-functional (non-secretory). Functional endocrine tumours of the pancreas usually present with symptoms caused by an excess of the secreted hormone and are rarely incidental. Non-functional endocrine neoplasms of the pancreas are more prone to be detected as incidental findings (incidentalomas) on intravenous contrast CT scans (Table 26.2) where they appear as small, well-vascularised, mass lesions (Fig 26.4). In general, endocrine neoplasms of the pancreas grow very slowly or not at all and, as with lymph nodes, investigation and management can be problematic as their true nature can be very difficult to determine with certainty. Transgastric endoscopic ultrasound scanning may help clarify the diagnosis, especially if endoscopic ultrasound scanning guided fine needle aspiration biopsy and cytology can be carried out (see Ch 17).

Table 26.2 Endocrine tumours of the pancreas

Figure 26.4 CT scan. Incidentally detected vascular pancreatic tail mass. Initial diagnosis: pancreatic neurendocrine tumour. Lesion is isodense with spleen. Final diagnosis: splenunculus.

Hepatic Incidentalomas

As with the pancreas, incidentally found masses of the liver may be due to congenital or acquired causes and may be cystic, solid or mixed cystic and solid. They may be non-neoplastic or neoplastic. Neoplastic hepatic incidentalomas may be benign or malignant and the malignant lesions may arise in the liver (primary hepatocellular carcinoma) or they may be metastatic from an extrahepatic primary site.

Cystic hepatic incidentalomas

Hepatic cysts are frequent incidental findings on abdominal cross-sectional imaging (ultrasound and CT). The great majority are non-neoplastic. Most are simple cysts requiring no further investigation or treatment unless they are symptomatic or there is diagnostic doubt.

Simple hepatic cysts

Simple hepatic cysts are more common in women than men, are lined by thin, smooth, epithelium and contain serous fluid. They do not connect with the biliary tree and they vary in size, ranging from only just detectable on scan (5 mm) to greater than 20 cm and palpable. These rarely require treatment although very large cysts may be symptomatic (abdominal discomfort or pain) and very occasionally they may cause abnormal liver function tests or even obstructive jaundice by compression of the bile duct. Simple cysts may be multiple, but this finding should raise the possibility of polycystic liver disease (Fig 25.5).

Figure 26.5 Abdominal CT. Incidentally detected simple hepatic cysts.

Polycystic liver disease

If the problem is true hepatic polycystic disease, there may be many, many cysts replacing most of the liver. An autosomal-dominant inherited disease, polycystic liver disease causes multiple hepatic cysts. Full expression of the defect also results in associated polycystic renal disease. Hepatic polycystic disease may cause enormous hepatomegaly, pain, jaundice and impaired liver function. Abdominal ultrasound scanning is the usual diagnostic tool. Needle biopsy is rarely indicated and should be utilised only in the context of a specialist, multidisciplinary unit.

Hepatic hydatid cysts

Viable (containing live hydatids) or non-viable (dead) hydatid cysts may be encountered as incidental scan findings, particularly in people from hydatid disease endemic rural areas. A history of contact with sheep and dogs is common, especially in a rural setting during childhood, and may not be clearly remembered. Plate-like or curvilinear calcification cyst wall calcification may be clearly visible on plain abdominal x-rays or CT scans of hepatic hydatid cysts.

Dead hydatid cysts tend to calcify and to collapse and may then show up on scans or on plain x-rays as amorphous, coarse, heavily calcified lesions with little or no residual cystic component. Provided other potentially viable hydatid cysts are excluded on the abdominal scan and chest x-ray examination, further diagnostic investigations are not usually required and calcified, non-viable hydatid cysts rarely require treatment.

Viable hydatid cysts show no calcification or incomplete calcification and non-uniform internal density due to daughter cysts or hydatid debris within the main cyst (Figs 26.6 and 26.7). Potentially viable hydatid cysts require careful investigation, even if they are truly asymptomatic, because of the risk of rupture into the peritoneal cavity. Hepatic hydatid disease must always be excluded before needling of hepatic cysts is considered as this procedure may result in leakage of hydatid cyst fluid containing viable hydatid protoscolices and cause intraperitoneal dissemination of the disease. Leakage of hydatid fluid into the peritoneal cavity may also cause acute hypersensitivity reactions. Hydatid serology may be positive in the presence of a non-viable cyst and is occasionally negative in the presence of a viable cyst. However, a positive test is a useful way of confirming that a patient has had hydatid disease at some time, but is not diagnostic of active hydatidosis.

Figure 26.6 Photograph taken during an operation on an hepatic hydatid cyst. Large liver hydatid cyst open to show daughter cysts within it. Hydatid daughter cysts cause the circular shadows seen within larger hydatid cysts on US and CT scans (see Fig 26.7).

Figure 26.7 Abdominal ultrasound scan. Daughter cysts in a large hepatic hydatic cyst.

Potentially viable hydatid cysts that are completely intrahepatic may safely be kept under observation after treatment with an antihelminthic agent such as albendazole. Cysts that discharge into the biliary tree may present with jaundice and are usually treated by endoscopic drainage to clear the bile duct. Further invasive treatment is not usually needed in these cases as bile contamination of the cysts kills the organisms, rendering the residual hepatic hydatid cyst non-viable. Cysts that are large involve the surface of the liver, become infected, are associated with compromise of liver function or are symptomatic usually do need treatment. This is usually surgical evacuation of the cyst plus an antihelminthic agent given before and after surgery to reduce the risk of postsurgical recurrence. See Table 26.3 for treatment of hepatic hydatid cysts.

Table 26.3 Treatment of hepatic hydatid cysts

Neoplastic hepatic cysts

Hepatic cystadenoma and their malignant form, hepatic cystadenocarcinoma, tend to be asymptomatic until quite large and so some will be detected incidentally on abdominal imaging. Surgical resection of hepatic cystadenomas, with clear resection margins achieved, should be curative. The hepatic cystadenocarcinoma is one of the few forms of hepatic malignancy with strong potential for cure if completely resected. Accordingly, though both these lesions are very uncommon, any patients in whom mixed cystic and solid hepatic cysts are detected require referral to a multidisciplinary specialist hepatic unit. The same advice applies to any other incidentally hepatic lesion in which there is diagnostic doubt or where invasive investigations or treatment modalities are required.

Solid hepatic incidentalomas

Solid hepatic lesions are more likely to be malignant than are cystic hepatic lesions. However, approximately 75% of solid liver lesions presenting as incidentalomas will be benign and the majority will also be non-neoplastic. The chance of a solid hepatic lesion being malignant does increase with age (especially over 55 years), if the lesion is palpable, if the liver function tests are abnormal and if known risk factors for primary or metastatic liver disease are present (Fig 26.8). These factors should be taken into consideration in assessing the risks associated with any particular solid hepatic incidentaloma.

Figure 26.8 Investigation of the incidental, scan-detected space-occupying lesion in the liver. AFP = α fetoprotein, CEA = carcino embryonic antigen; c/w = consistent with; CXR = chest x-ray; CT = computed tomography.

Hepatic fat deposition and rare tumours

Focal irregularities in distribution of fat (focal excess or absence) detected within the liver on ultrasound or CT scanning can give the appearance of a mass lesion (in this context, a hepatic incidentaloma). Focal fat deposition is most commonly seen in segment four of the liver, adjacent to the ligamentum teres. This characteristic location and other radiological characteristics mean that most focal fat deposits in the liver are recognised as such by the radiologist.

Rare liver lesions which may be asymptomatic and detected unexpectedly include teratomas, large biliary adenomas and myxomas. The imaging findings are unlikely to be conclusively diagnostic and will usually mandate other investigations for which referral to a multidisciplinary hepatic unit will be required.

Radioactive pharmaceutical imaging in the investigation of hepatic masses

Radionuclide scans exploit the capacity of certain tissues to selectively concentrate a radioactive labelled tracer. However, these tests are often not specifically diagnostic and the information gathered is usually functional rather than anatomical. The need for precise anatomical and diagnostic information in the detection and anatomical assessment of abdominal masses has led to a decline in the use of radioisotope scanning in favour of cross-sectional imaging (ultrasound, CT and MRI) to detect liver masses and to characterise them anatomically. However, the ability of some radionuclide scans to reveal the functional characteristics of an abdominal mass or to exploit specific functional characteristics (such as glucose avidity) to reveal the presence of anatomically undetectable masses is still useful in characterising some hepatic masses, in staging some malignancies that have presented as hepatic masses or that have a propensity to spread to the liver, for assessing treatment responses and in surveillance for post-treatment recurrences.

Liver/spleen scan

This scan may be useful in characterising hepatic adenomas. The radiopharmaceutical is bound to a colloid. The colloid facilitates uptake by hepatic reticuloendothelial (Kupffer) cells to give an outline of the whole of the liver. This whole-organ affinity for the colloid carrying the radioactive marker can then be used to delineate masses that do not contain Kupffer cells. Such masses (e.g. colon carcinoma metastases) will then appear on the scan as ‘cold’ or ‘photopaenic’ areas in the liver scan. Liver cell adenomas lack Kuppfer cells and so also tend to be photopaenic.

Labelled red cell scan

This scan is particularly useful in the diagnosis of hepatic haemangiomas. Venous blood is drawn from the patient and mixed with a radioactive marker that attaches to the red cells. The blood, now tagged with the radioactive marker, is then injected back into the patient and the patient is scanned. Haemangiomas typically show progressive accumulation of radiolabelled red blood cells. This causes slowly evolving focal ‘hot’ spots on the labelled red cell scan consistent with slow venous flow into a haemangioma, into the periphery of the lesion first, then to the centre of the lesion.

Biliary scan

Usually named according to the tracer used (HIDA or DisHIDA), this scan is occasionally requested for diagnosing cystic duct obstruction (especially suspected acute cholecystitis), checking flow of bile out of the liver through a bilioenteric anastomosis or stent and in characterising focal nodular hyperplasia. The injected contrast agent is taken up by hepatocytes and is then rapidly excreted from the hepatocyte into the bile duct radicals and transported out of the liver in the bile ducts to be discharged from the common bile duct into the duodenum.

Biliary scanning is still occasionally useful in assessing patency of the cystic duct to help establish a diagnosis of acute cholecystitis and to demonstrate non-function of the gallbladder due to chronic cholecystitis (gallbladder fibrosis). In the normal biliary tree, in the fasting state, the sphincter of Oddi will be closed and bile will be diverted into the gallbladder where water will be reabsorbed across the gallbladder mucosa to concentrate the gallbladder bile. If the cystic duct is obstructed by a gallbladder stone (as in acute cholecystitis) or if the gallbladder is scarred and contracted due to fibrosis from previous cholecystitis, bile will not enter the gallbladder and the gallbladder will not appear on the scan. If a stent in the bile duct has become obstructed, the tracer will accumulate in the liver and in the biliary tree above the stent, but will not appear in the duodenum or will be very slow to do so.

Biliary scanning can also be useful in characterising liver masses when the diagnosis remains unclear after cross-sectional imaging, liver-spleen scanning and labelled red cell scanning. Masses caused by fibronodular hyperplasia contain functioning hepatocytes, but have few biliary drainage radicals. Fibronodular hyperplasia will therefore tend to take up and hold a radiolabelled tracer excreted into the bile. Therefore, fibronodular hyperplasia will initially appear isodense with the rest of the liver. But, due to its deficiency of biliary drainage radicals, fibronodular hyperplasia will hold the tracer and therefore appear as a delayed hot spot on the biliary scan after the normal liver has cleared the radiolabelled tracer into the biliary tree.

Positron emission tomographic scan

The positron emission tomographic scan (PET) is not specifically a liver mass scan. The bio-window exploited in this scan is the high glucose uptake and metabolism exhibited by some malignancies. A glucose analogue radiopharmaceutical will accumulate in the glucose pathway, and tissues utilising this pathway more than surrounding tissues do will stand out as hot spots on the scan. This is particularly useful for staging some malignancies, for confirming that a mass is malignant, for assessing treatment results and for surveillance for post-treatment recurrence.

Other radionuclide scans for liver masses

Gallium scans can highlight lymphoma, metastatic melanoma, hepatoma and inflammatory collections. However, as gallium is also taken up by normal liver parenchyma it is of limited value in assessing liver masses. Scanning for neurendocrine tumours (e.g. carcinoid) can be more specific and can be useful for characterising the primary tumours and their liver metastases by utilising 111-indium pentetreotide (octreotide) as the scanning tracer or indicator.

Other radionuclide scans for other abdominal masses

A number of racers are available for specific circumstances but are uncommonly used as initial investigations. These include radioiodine-labelled MIBG (iodine-131-meta-iodobenzylguanidine) for phaeochromocytoma and paraganglioma and labelled white cell scans for inflammatory bowel disease and inflammatory collections.

Invasive diagnostic procedures in the diagnosis of hepatic masses

The highest order diagnosis possible should be sought for potentially treatable lesions in patients likely to be able to tolerate and benefit from treatment. Achieving a confident diagnosis may require invasive investigations. The risks of these must be outweighed by the potential benefits. Invasive investigations require fully informed consent by the patient and family and should be undertaken only with appropriate specialist advice as part of an overall management plan. Such investigations include:

• endoscopy: this is of particular value when the hepatic lesion is thought to be a metastasis from an upper or lower gastrointestinal tract primary cancer;

• endoscopic ultrasound of the pancreas: this may be appropriate if a liver lesion is thought to be a pancreatic metastasis. Pancreatic cancer with hepatic or other visceral metastatic spread is incurable, treatment intent is palliative and surgical intervention is usually contra-indicated;

• biopsy: finalising the diagnosis and treatment plan often requires biopsy for cytopathology or histopathology. Even though the procedural risks are generally low, biopsy of a liver mass by any method will always entail some risk. Risks include bleeding from vascular lesions, tumour rupture and spread by seeding of tumour along a biopsy track or into the peritoneal cavity. Needle biopsy of liver masses should be avoided if the lesion is cystic, if there is any likelihood that the tumour might be malignant and amenable to potentially curative surgical excision, might be vascular and prone to bleeding and/or rupture or the patient has comorbidity likely to be associated with bleeding. Surgical excision biopsy should be considered for liver adenomas, some hepatomas and some liver metastases. Liver biopsy should not be undertaken until these possibilities have been considered. This will usually require a multidisciplinary approach including surgical consultation;

• angiography: selective cannulation of the coeliac or superior mesenteric arteries is only occasionally required. Modern cross-sectional imaging yields high quality images of liver lesions. All the information required for clinical decision making should be available from the arterial and portal venous phases of triple-phase CT scans;

• laparoscopy: this is occasionally useful when the imaging diagnosis remains uncertain. Direct visualisation of the liver mass may help clarify this or permit safer biopsy than by the percutaneous route.

Retroperitoneal Masses

Tissues of origin for retroperitoneal incidentalomas may include lymph nodes, mesenchyme and nerves of the sympathetic chain or of the somatic neural network.

Lymph node masses

Retroperitoneal lymphadenopathy may be reactive (inflammatory) or neoplastic (malignant). Reactive lymphadenopathy is usually a response to inflammation somewhere in the draining field of that lymph node but can also be part of a diffuse inflammatory response. Reactive nodal enlargement is usually modest, non-progressive and temporary. Malignant retroperitoneal lymphadenopathy tends to be progressive and may be quite bulky, particularly when due to malignant lymphoma (Fig 26.11). Lymphadenopathy due to metastatic carcinoma is usually slowly but inexorably progressive whereas that due to lymphoma may fluctuate, particularly early in the course of the disease. Close questioning of lymphoma patients may uncover systemic symptoms (e.g. fever, rash, pruritus) and careful examination may detect enlarged lymph nodes in the groin, axilla or neck. In patients with metastatic skin cancer (squamous cell carcinoma or melanoma), there may be a history of a mole or lump, which may have been ignored, may have regressed or may have been previously removed. Some of the more common visceral primary sites leading to unexpected retroperitoneal masses (usually nodal) include the colon, stomach, pancreas and testis. There may be previously unrecognised or undetected symptoms arising from the nodal mass or from the primary lesion, or there may be signs in the organ draining to the site. There may also be non-specific symptoms consistent with malignancy, such as lethargy or weight loss.