A Child With a Pancreatic Mass

A 6-year-old girl came to our outpatient department with complain of mild pain abdomen for 2 months. On physical examination, she was thriving well with normal anthropometric parameters for her age. Her abdominal and other systemic examination was unremarkable. Her routine laboratory tests showed normal hemogram, liver and renal function tests, and normal serum amylase and lipase. However, abdomen ultrasonography showed a heterogeneous mass lesion in the head of the pancreas (19 × 18 mm). Subsequently, abdominal MRI was done and showed well-defined T1 hypointense, T2 hyperintense mass lesion in the head of the pancreas with the rest of the pancreas and pancreatic duct being normal (Figure A, B). Endoscopic ultrasonography (EUS) with guided fine needle aspiration (FNAC) from the mass lesion was done (Figure C, D).

What is the likely diagnosis?

Solid pseudopapillary tumors (SPT) are indolent and potentially malignant neoplasms that constitute 4% of resected pancreatic cystic neoplasms. They are more common in females in their second to fourth decades and most often diagnosed incidentally, but may present as acute pancreatitis, jaundice, and palpable mass. In view of their malignant potential, young age at onset, and excellent postoperative survival rate (5-year survival rate of 95%), surgical resection is the treatment of choice.

MRI is better than computed tomography at detecting the cystic or solid components of SPT and shows 3 specific features. Type 1 is an SPT with completely solid parts, which is homogenously hypointense on T1-weighted imaging and slightly hyperintense compared with the pancreas parenchyma on T2-weighted imaging. Type 2 is SPT with solid mass with hemorrhage. Type image is SPT with massive hemorrhage. If MRI reveals an encapsulated mass with solid and cystic components as well as hemorrhage without obvious internal septum, that is, a type 2 or 3 image, SPT of the pancreas is highly suspected. In our case, abdominal MRI (Figure A, B) showed s well-defined mass, which was hypointense on T1-weighted imaging and hyperintense on T2-weighted imaging, or a type 1 SPT, without obvious hemorrhage.

Another consideration in the differential diagnosis was pancreatoblastoma, which is more commonly seen in the first decade of life as pancreatic head mass (in two-thirds). It has the distinct histologic features of typical squamoid corpuscles and tumor cells with acinar, glandular, or undifferentiated appearance. Thus, EUS-guided FNAC was done to establish the diagnosis as prognosis and treatment differs with the type of tumor.

EUS can show both solid and cystic components, a hypoechoic mass, and even calcifications in the tumor. EUS FNAC shows branching papillary fragments composed of vascular stalks with a perivascular amorphous myxoid substance decorated by bland-appearing tumor cells.

In our case, EUS showed a well-defined hypoechoic mass (size 26 × 23 mm) with increased vascularity in head of pancreas (Figure C). EUS-guided FNAC of the mass showed papillary fronds with a central vessel, surrounded by stromal layer and outer layer of monomorphic neoplastic epithelial cells (Figure D). The patient underwent radical resection of the tumor and is doing well in follow-up to date.