A case of intrapancreatic accessory spleen mistaken as a pancreatic mass due to different enhancing pattern from normal spleen

Accessory sple­en in a dog: Macroscopic and microscopic findings

Accessory spleens are one or more areas of normal ectopic splenic tissue of variable size supplied by the branches of the splenic artery. A 7 year-old mixed breed male dog was fixed for use as a model in anatomy hall. During the abdominal dissection, the gross examination showed a 6.3×3.1×1 cm mass that was situated on the caudodorsal border of the spleen. Its appearance and firm consistency were similar to those of spleen. There was no connection between the spleen and this mass. It was supplied by accessory splenic artery. Microscopic examination of the mass revealed some structures similar to spleen.

Intrapancreatic accessory spleen: Evaluation with CT and MRI

The aim of the present study was to evaluate the characteristics of computed tomography (CT) and magnetic resonance imaging (MRI), particularly diffusion-weighted imaging (DWI), in the imaging of intrapancreatic accessory spleen (IPAS). The clinical and pathological records of 9 patients, including 8 patients with IPAS and 1 patient with splenosis, were reviewed. The patients had undergone plain and triple-phase enhanced CT scanning (n=9) and MRI scanning (n=8). The lesions of the 8 IPAS patients were located in the pancreatic tail, and were round (n=3), oval (n=4) or triangular (n=1) in shape. The CT and/or MRI densities, signal intensities and dynamic enhanced patterns of the lesions were similar to those of the orthotopic spleen. In DWI images (n=5), the IPAS regions presented high signal intensity (SI), and no significant difference in the apparent diffusion coefficient determined using a b-value of 600 sec/mm² was identified between the IPAS and orthotopic spleen (P>0.05). One patient with splenosis complicated with cirrhosis had a nodule located in the pancreatic tail with an unenhanced CT value of 65 HU. In MRI examination, with the exception of the dynamic enhancement pattern, the T1-weighted, T2-weighted and DWI signals of splenosis were inconsistent with those of the normal spleen. In conclusion, in pre-contrast and post-contrast-enhanced CT and MRI images, IPAS exhibits similar characteristics to the orthotopic spleen. CT and MRI used in combination with DWI are important in the diagnosis of IPAS.

Errors and mistakes in the ultrasound diagnosis of the pancreas

The differential diagnosis of the focal lesions in the region of the pancreas is difficult due to the similarity of clinical and radiological pictures of neoplastic and non-neoplastic lesions. This paper presents the most common causes of errors in ultrasound diagnosis of pancreatic pathologies. Attention was paid to the errors resulting from the structural variants of the pancreas and those caused by the neighborhood of intestine, stomach and other organs or vessels. Moreover, the article presents mistakes in the interpretation of ultrasound images of normal pancreas as well as its inflammatory and neoplastic lesions. The errors and mistakes in question were divided into three categories: 1) mistakes related to the anatomical structure of the pancreas (anatomical variants, echostructure and echogenicity, course of the splenic artery); 2) mistakes related to anatomical structures localized in the vicinity of the pancreas (caudate lobe of the liver, other organs and intestinal loops surrounding the head of the pancreas, vessels and bile ducts, lymph nodes in the region of the pancreas or duodenal diverticula and tumors); 3) mistakes related to the pathologies of the pancreas (inflammatory and neoplastic lesions including differentiation between inflammatory tumors and malignant masses). In spite of the progress of imaging techniques, the differential diagnosis of focal solid lesions remains the prime problem of imaging examinations of the pancreas. The major aim of the ultrasound examination is early detection of pancreatic neoplasm. Improper performance of the examination or a failure to perform a repeated scan when the conditions for the assessment of the pancreas are not favorable or, what is worse, description of normal pancreas when it is not clearly and entirely visible, constitute errors.