When Tell tail signs lie Nabil Sherif Mahmood

When Tell ‘tail’ signs lie Nabil Sherif Mahmood *, Ravivarma Balasubramaniam *, Biju Thomas *, Anitha James *, Ingrid Britton*, Nicola Cook*, Sahithi Nisthala *, Vincent Leung* and Cordelia Howitt $ *G. I and Body Imaging division, Royal Stoke University Hospital Department of Pathology , Royal Stoke University Hospital $ Email : Nabil. Mahmood@uhnm. nhs. uk

Clinical history • 70 year old male patient underwent CT abdominal aortogram for evaluation of AAA. • Recently diagnosed Type II diabetes. • No unintentional weight loss , loss of appetite or other symptoms.

Fig 1 A Fig 1 B Axial Contrast CT aortogram ( Fig 1 A and 1 B )shows diffuse enlargement of the pancreatic tail with a surrounding halo and thin rim. There is posterior peri-pancreatic extension of the abnormality encasing the splenic artery ( Fig 1 A).

Fig 1 C Fig 1 D Axial Contrast CT aortogram ( Fig 1 C and 1 D )shows normal pancreatic head.

Fig 2 A Fig 2 B Axial T 2 W MRI abdomen ( Fig 2 A and 2 B )shows abnormal pancreatic body with irregular dilatation of the main pancreatic duct as well as the side branch ducts through out the abnormal segment. A thin hypointense rim can be seen surrounding the tail. The posterior peri-pancreatic extension encasing the splenic artery is appreciated in Fig 2 A. Incidental splenic and renal cysts are seen.

Fig 2 C Fig 2 D Axial early ( Fig 2 C) and delayed ( Fig 2 D ) Post contrast T 1 W Fat supressed images show abnormal pancreatic tail. There is heterogeneous enhancement in both phases with a low intensity hypo-enhancing area in the proximal tail that is seen to persist in the delayed phase. Note the continuation of the irregular ductal dilatation across this region. The thin enhancing rim is better appreciated in the distal tail anteriorly ( Fig 2 D).

Fig 2 E Axial DWI(2 E) and ADC ( Fig 2 F) images shows restricted diffusion within the abnormal segment. Fig 2 F

Lab results • • • Ca 19 -9 : 651 U/m. L Hba 1 c : 62 mmol/mol S. Amylase : 60 U/L LDH : 188 U/L Phosphate : 0. 9 mmol/L Mg : 0. 81 mmol/L CRP : 58 mg/L Hb 116 g/L WCC : 8. 5 x 109/L

Diagnosis ? Focal Autoimmune Pancreatitis Pancreatic Cancer • Sausage shaped tail • Surrounding halo and rim • Positive duct penetrating sign • Vascular encasement • Heterogeneous enhancement • Elevated CA 19 -9 Provisional Diagnosis : Pancreatic Cancer Plan : Staging Laparoscopy and Distal Pancreatectomy

Staging Laparoscopy Findings: • No evidence of peritoneal or liver metastasis. No ascites. Pelvis and omentum appeared normal.

Distal Pancreatectomy Findings: • Head of pancreas was reasonably soft. Hard mass in the body with tumour adherent to splenic vein and artery

Histopathology Macroscopy • Subtotal pancreas; body/tail of pancreas measuring 130 x 60 x 35 mm. The anterior surface was covered with shiny peritoneum and the posterior surface was ragged. Sectioning revealed a relatively wellcircumscribed creamy white/pink tumour 84 mm in maximum diameter.

Histopathology Clear Cell variant of Ductal type adenocarcinoma of the pancreas - p. T 3 p. N 0 V 1 R 1 Clear Cell variant of PDA Conventional PDA

Discussion • Distinguishing focal AIP from Pancreatic cancer can be difficult. • 3 -5% of patients undergoing resection for pancreatic cancer in fact have AIP. • Can MRI Pancreas better delineate the pancreatic tumour compared to conventional post-contrast CT ?

Discussion

Discussion

Key Learning Points • Distinguishing focal Autoimmune pancreatitis from Pancreatic cancer is important. • Sausage shaped enlargement , peripancreatic halo and rim and positive duct penetrating sign are usually considered characteristic of AIP. • However these signs can rarely be seen with pancreatic cancer as well and should not be used to exclude the diagnosis especially in the presence of other imaging findings such as vascular encasement and raised tumour markers.

Thank you