Pancreatoblastoma - A Rare Pediatric Pancreatic Tumor.

A 12-year-old male child, who was previously well, complained of pain and lump in abdomen. Physical and radiological investigations revealed a mass in pancreas. Histopathological examination of the resected specimen showed pancreatoblastoma. Pancreatoblastoma is an unusual malignant tumour seen in infants and children although rare cases have also been reported in adults. They are clinicopathologically distinct from adult pancreatic ductal carcinoma. The histogenesis, clinical features and treatment options are discussed along with presentation of the case. Pancreatoblastoma is a rare distinct neoplasm that is most commonly encountered in infants and young children, although rare cases have been reported in adults. They comprise 0.5- 1% of pancreatic tumors. Pancreatoblastoma was first described by Frantz in 1959. Subsequently, Frable et al in 1971 described the histological and ultrastructural findings and called it as "infantile carcinoma of pancreas". These tumors are considered to be embryonic in origin, based on the histological appearance. Evidence of endocrine component, acinar cells containing zymogen granules and the presence of alpha-foetoprotein, suggests that this neoplasm arises from multipotential stemcells. A potential molecular association between pancreatoblastoma and hepatoblastoma is suggested by the occurrence of both tumors in young patients with Beckwith-Wiedemann syndrome, raising the possibility that genetic events on chromosome 11p might play a role. The clinical presentations of these tumors are varied. They can present as abdominal pain, abdominal mass, diarrhoea, or upper gastrointestinal bleeding. Most of the time, they are asymptomatic. The presenting features are highly non-specific and this leads to diagnostic dilemmas. The tumor is slightly more frequent in males, with the median age of presentation being five years. Though malignant, these tumors have an indolent course. They can be cured by complete resection alone and in cases of unresectable tumors, incomplete resection and in those with metastatic lesions, radiotherapy or chemotherapy may be given. The prognosis is worse in the presence of synchronous or metachronous metastasis and non-resectable disease at presentation, (1). II. Case Report A 12-year-old boy presented with pain and swelling in the upper abdomen and had vomitings. The vomitus contained only ingested food particles. Patient also had few episodes of loose stools. Physical examination revealed a slightly tender lump in the epigastrium and left hypochondriac region. The rest of the abdomen was soft and non-tender. Bowel sounds were sluggish. Ultrasonography of the abdomen showed a well-defined heterogeneous mass in the epigastric region measuring 6.4x5. 5x2 cm. This mass was situated medial to the spleen and was compressing the stomach. Computed tomography (CT) of abdomen showed a well- defined cystic mass in the region of pancreatic tail. (Fig. 1 & 2). The contents antigen, serum amylase and alpha- foetoprotein were all within normal limits. The patient underwent exploratory laprotomy for resection of the mass in the pancreas. Intra operatively, there was a well-defined encapsulated firm mass arising from the body of pancreas adherent to mesocolon and lesser sac of stomach. The mass was adherent to retroperitoneum and surrounding structures except spleen This cystic mass was resected piecemeal. Grossly, the resected tumor was globular and encapsulated, measuring 7x6x3 cm and weighing 180g. The surface was bossellated and the tumour was soft in consistency. Serial cut sections revealed a greyish white solid tumor with central area of haemorrhage and necrosis. Microscopical examination of this resected tumor showed pancreatic tissue and a tumor that was arranged in glandular and acinar pattern with interspersed focal solid areas. In the solid areas, whorled nests of spindle cells and islands of plump epithelioid cells were seen (Fig. 3 & 4). Extensive tumor necrosis was also present. The tumor cells showed diffuse strong positivity for alpha-foetoprotein . After surgery, the patient was referred to our Deptt. for further management. He was started on PLADO (Cisplatinum &Doxorubicin) based chemotherapy . He received one cycle of PLADO based chemotherapy and later was lost to follow up.