Imaging findings of intraductal tubulopapillary neoplasm (ITPN) of the pancreas: Two case reports and literature review

Abstract

Rationale: Intraductal tubulopapillary neoplasm (ITPN) is a rare type of pancreatic epithelial neoplasm. We report 2 cases of ITPN and detail the imaging findings.

Patient concerns: The 1st case was a 36-year-old woman who complained of jaundice, yellow urine and diarrhea. She accepted ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI) examination before surgery, which all revealed a mass in the pancreatic head. The 2nd case was a 62-year-old woman who was admitted to our hospital for the treatment of a pancreatic tumor. The MRI showed a mass filled the mian pancreatic duct in the head and neck.

Diagnosis: The ITPN is an intraductal, grossly visible, tubule-forming epithelial neoplasm with high-grade dysplasia and ductal differentiation without overt mucin production.

Interventions: The 1st patient received percutaneous transhepatic cholangial drainage procedure, endoscopic ultrasound guided fine needle aspiration, pancreatoduodenectomy, cholecystectomy, and lymphadenectomy successively. The 2nd patient received pancreaticoduodenectomy, cholecystectomy, and partial gastrectomy.

Outcomes: Two months after surgery, the follow-up MRI revealed hepatic metastasis of the 1st patient. She is still alive now. The 2nd patient was lost to follow-up.

Lessons: The ITPN is a rare pancreatic neoplasm and its clinical symptoms are atypical. It is difficult to make accurate diagnosis of ITPN before surgery even though various imaging modalities are used in combination. When a solid mass growing in the lumen of the pancreatic duct, ITPN should be taken into consideration.

Figure 1

Case 1, female, 36-year-old, intraductal tubulopapillary neoplasm with invasive carcinoma (white arrowheads, the mass; white arrows, the dilated pancreatic duct in the pancreatic body and tail; black arrows, the tumor inside the dilated pancreatic duct). Endoscopic ultrasonography (A) revealed an ill-defined hypoechoic mass in the head of the pancreas. Unenhanced CT scan (B) showed the mass was low attenuating, associated with the atrophy of pancreatic parenchyma and dilation of the main pancreatic duct in the body and tail. Contrast-enhanced CT (C, arterial phase; D, portal phase; E, delayed phase) showed the mass was relatively hypovascular compared with the normal pancreatic parenchyma. The CT curved planar reformation image (F) of the portal phase along the direction of the main pancreatic duct showed the 2-tone duct sign clearly, indicating both the low attenuating tumor and lower attenuating fluid inside the dilated pancreatic duct. CT = computed tomography.

Figure 2

Case 1, female, 36-year-old, intraductal tubulopapillary neoplasm with invasive carcinoma (curves, the mass; dotted arrow, the common bile duct; solid arrow, the dilated pancreatic duct). The MRI (A, fat suppression [FS]-T2WI; B, DWI; C, ADC; D, unenhanced FS-T1WI; E–J, dynamic contrast-enhanced FS-T1WI in sequential order; J, DWI; K, MRCP) demonstrated the mass was slightly hypointense on FS-T1WI, slightly hyperintense on FS-T2WI, hyperintense on DWI and hypovascular compared with the normal pancreatic parenchyma. The ADC value was low. The MRCP revealed abrupt disruption of the common bile duct in the region of the mass, twist and dilation of the main pancreatic duct in the pancreatic body and tail, and obvious dilation of intrahepatic and extrahepatic bile ducts. Microscopic image of haematoxylin-eosin staining (L, magnification x100) showed the tumor consisted of closely apposed tubules forming complex cribriform structures in dilated pancreatic ducts with focal areas of papillary architecture. The normal ductal epithelium can be seen surrounding the tumor. ADC = apparent diffusion coefficient, DWI = diffusion weighted imaging, FS = fat suppression, MRCP = magnetic resonance cholangiopancreatography, MRI = magnetic resonance imaging, T1WI = T1-weighted imaging, T2WI = T2-weighted imaging.

Figure 3

Female, 62-year-old, intraductal tubulopapillary neoplasm with microinvasive carcinoma (arrowheads, the mass; arrows, the dilated pancreatic duct). The MRI (A and B, FS-T2WI; C, DWI; D, ADC; E–H, FS-TIWI [E, unenhanced scan; F, arterial phase; G, portal phase; H, delayed phase]) showed the mass was located in the dilated main pancreatic duct, hypointense on FS-T1WI, slightly hyperintense on FS-T2WI, hyperintense on DWI and hypovascular compared with the normal pancreatic parenchyma. The ADC value was low. The FS-T2WI showed the mass was markedly hyperintense and the fluid was slightly hyperintense inside the dilated pancreatic duct, which constituted the 2-tone duct sign. Microscopic image of haematoxylin-eosin staining (I, magnification x400) showed closely arranged tubules grow in the way of back to back, forming nodular structures in the dilated pancreatic duct. The tumor cells were cuboidal and low columnar in shape with a moderate amount of eosinophilic or amphophilic cytoplasm and round to oval nuclei of moderate to severe atypia. ADC = apparent diffusion coefficient, DWI = diffusion weighted imaging, FS = fat suppression, MRI = magnetic resonance imaging, T1WI = T1-weighted imaging, T2WI = T2-weighted imaging.