Cytogenetically confirmed primary Ewing's sarcoma of the pancreas

Abstract

Ewing's sarcoma is a highly aggressive malignant tumour most commonly affecting long bones in children and adolescents. It is part of the Ewing's sarcoma family of tumours (ESFTs) that also include peripheral primitive neuroectodermal tumour and Askin's tumours. ESFTs share common cytogenetic aberrations, antigenic profiles and proto-oncogene expression with an overall similar clinical course. In 99% of ESFTs, genetic translocation with molecular fusion involves the EWSR1 gene on 22q12. Approximately 30% of ESFTs are extraosseous, most commonly occurring in the soft tissues of extremities, pelvis, retroperitoneum and chest wall. Primary presentation in solid organs is very rare but has been described in multiple sites including the pancreas. Accurate diagnosis of a Ewing's sarcoma in a solid organ is critical in facilitating correct treatment. We report the case of a 17-year-old girl with cytogenetically confirmed primary pancreatic Ewing's sarcoma and provide a brief review of the published literature.

Keywords: Extraosseous Ewing’s sarcoma; Primary pancreatic Ewing’s sarcoma; Primitive neuroectodermal tumor; peripheral primitive neuroectodermal tumor (pPNET).

Figure 1

Whole-body ⁶⁸Ga-labelled (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid)-1-Nal³-octreotide PET CT scan showing a large mildly DOTA NOC avid mass lesion in the head and uncinate process of the pancreas abutting and compressing the CBD as well as the second and third portions of the duodenum.

Figure 2

Histopathological features of the tumour are shown. (A) Low power image showing tumour with adjacent pancreas (H&E staining). (B) High power magnification of tumour showing atypical small cells with scant cytoplasm. (C) Immunohistochemistry showing strongly CD99-positive cells. (D) Two-colour fluorescence in situ hybridization (FISH) assay probe showing EWSR1 break apart with one red and one green signal. (E) EWSR1-FLI1 dual fusion FISH probe showing FFRG signal pattern. (F) Reverse transcription (RT)-PCR image: lane A, RT-PCR with primers to EWSR1-FLI1 transcript; lane B, negative control (no target in reaction); lane C, negative control (negative complementary DNA); lane D, positive control (type 2).

Figure 3

Postoperative fluorodeoxyglucose (FDG) positron emission tomography scan showing focal FDG uptake in the operative bed in the region of the head of pancreas and an ill-defined uptake along the resected margin of the pancreas without evidence of any separate primary lesion.