G Watts, D Sadashivan, V Gopalan, S Sharma
aetiology, emboli, ischaemia, myxoma, pancreatitis
G Watts, D Sadashivan, V Gopalan, S Sharma. Left Atrial Myxoma Presenting with Acute Pancreatitis. The Internet Journal of Thoracic and Cardiovascular Surgery. 2006 Volume 8 Number 2.
We report the first published case of a left atrial myxoma presenting with acute pancreatitis. Left atrial myxomas usually present with one or more of the classical triad of symptoms including; manifestations of mitral valve obstruction, signs of systemic embolisation or constitutional symptoms. More than two-thirds of embolic phenomena involve the central nervous system and there are no previous reports of tumour emboli to the pancreas. The constitutional symptoms of cardiac myxoma have been related to the production of Interleukin 6 (IL-6), a principle mediator of the acute phase protein response. IL-6 has also been demonstrated to influence the pathogenesis of pancreatitis. Pancreatitis secondary to atrial myxoma may be related to tumour emboli and influenced by serum IL-6 secreted from the myxoma.
A 44 year-old female presented to the emergency department with sudden onset of sharp epigastric pain radiating to her back, fevers, sweats, nausea and vomiting. The patient had been recently well with no significant past medical or family history. She was not on any current medications and had only occasional alcohol intake.
On arrival she had low grade temperature with other vital signs normal, abdominal examination demonstrated epigastric tenderness and localised guarding with no rebound tenderness. Cardio/respiratory examination was normal. Blood tests demonstrated a white cell count of 19.9x10 9 /L (4-11x10 9 /L), lipase of 742 U/L (<60U/L) and amylase 486 U/L (<100U/L).
The patient was diagnosed with pancreatitis. Abdominal ultrasound demonstrated a normal biliary tree and an absence of cholelithiasis or choledocholithiasis. Abdominal CT scan demonstrated mild pancreatic oedema with multiple small renal and splenic infarcts. A source of arterial emboli was suspected. A transthoracic echocardiogram demonstrated a large left atrial echogenic mass attached to the interatrial septum with dimensions of 3.0 x 2.8 cm and friable elements near the mitral valve.
The patient was taken for emergency excision of the mass under cardiopulmonary bypass and systemic cooling to 32°C. Through an extended transeptal approach, the mass had a broad based attachment encompassing much of the atrial septum. This was resected en mass. No other cardiac lesions were noted at the time of surgery. The septum was closed primarily. Formal histopathology confirmed a left atrial myxoma without evidence of malignancy and clear surgical margins [Figure 1].
Post operatively the patient demonstrated a smooth recovery with resolution of her abdominal complaints and return to baseline of her lipase and amylase [Figure 2].
She did not develop any further complications of pancreatitis. The patient was discharged 6 days post surgery. No further recurrence of pancreatitis was noted at one-month follow-up.
A literature search was conducted on Medline using the key words myxoma, pancreatitis, aetiology, ischaemia and emboli. No articles were identified associating pancreatitis and cardiac myxoma. This clinical case is thus unique and raises comment on the underlying pathogenesis of the pancreatitis.
Cardiac myxomas were first described in 1845 by King and are the most frequent benign tumours of the heart with an incidence up to 0.19% in unselected patients at autopsy . With modern day investigations and surgical intervention these once inoperable tumours can be identified and resected with mortality rates of 3% depending mainly on the age of the patient and co-morbid conditions . The tumours have the potential to remain clinically silent until presentation or may present with a variety of symptoms making diagnosis difficult. The classical triad for left atrial myxoma includes manifestations of mitral valve obstruction, signs of systemic embolisation or constitutional symptoms and together they account for the propensity for clinical diversity . Systemic emboli are responsible for much of the long term morbidity, particularly cerebrovascular and coronary events. With adequate tumour resection recurrence rates are as little as 1-3% in sporadic cases but rises in familial and multicentric disease to between 12 and 22% respectively .
Tumour embolisation of abdominal viscera has been quoted at around 6% with renal, splenic and hepatic emboli recorded . There are no published accounts involving the pancreas. The pancreas is an organ highly susceptible to ischaemic injury as evidence by experimental studies and in the clinical settings of cardiopulmonary bypass, haemorrhagic shock, selective embolisation of pancreatic vessels and pancreatic transplants . Ischaemia and reperfusion in the ex vivo pancreas induces parenchymal oedema and the release of amylase and lipase into the perfusion fluid . These morphological changes are matched in animal models, with the progression to irreversible necrotizing pancreatitis if the ischaemic insult is repeated and haemorrhagic pancreatitis if there is subsequent reperfusion [6,7].
The IL-6 family plays a central role in the pathophysiology of cardiovascular diseases . More recently cardiac myxomas have been demonstrated to produce IL-6 mRNA and IL-6 protein in vitro and raised serum levels become undetectable after tumour resection . IL-6 is the principle mediator of the acute phase protein response and overproduction has been linked to the prominent constitutional symptoms such as fever, anaemia and arthralgia experienced by patients with cardiac myxomas . The activation of inflammatory cells during acute pancreatitis is responsible for the release of inflammatory mediators into the circulation including IL-6, influencing both the local and systemic severity of disease . IL-6 has proved to be a predictable marker of severity and outcome of pancreatitis. IL-6 transgenic mice have been demonstrated to show reduced severity of induced acute pancreatitis when pre-treated with IL-6 antibody compared to mice who do not receive the antibody .
In conclusion, we present a unique case of pancreatitis cause by left atrial myxoma. Although the exact aetiology is unclear we postulate that pancreatic ischaemia secondary to tumour emboli caused the acute pancreatitis that may have been potentiated by high circulating levels of IL-6.
Guy Watts PO BOX 5115 Dalkeith 6009 Perth, Western Australia Phone (h) +61 8 9389 9150 (m) 0417 915 653 firstname.lastname@example.org