Accessorial spleen within the pancreatic tail as differential diagnosis to pancreatic tumour

Purpose: Accessorial spleens are often incidental findings in abdominal ultrasound. Because of their echogenicity and behavior in contrast enhanced ultrasound they can be misjudged as malignant tumours if found in an atypical location.

Material and methods: During routine abdominal ultrasound a small round slightly hypoechoic lesion without halo was detected within the pancreatic tail of three persons (size 8 – 20 mm). EUS and CEUS have been performed as well as contrast enhanced MRI, which showed a hyperenhancing lesion without washout. Two lesions have been punctured, one lesion has been operated (pancreatic tail resection and splenectomy).

Results: All three lesions were histologically confirmed as being accessorial spleens within the pancreatic tail.

Conclusion: Accessorial spleen in the pancreatic tail is an important differential diagnosis to NET tumors of the pancreas. Accessorial spleens show a moderate hyperenhancement and washout together with the normal spleen tissue during CEUS. A histological/cytological diagnosis by EUS puncture should be performed before operation is performed.