Peripheral Primitive Neuroectodermal Tumor with Postchemotherapy Neuroblastoma-Like Differentiation

Abstract

We report the case of an 11-year-old girl with a retroperitoneal tumor in the left upper quadrant. The girl was admitted to hospital with weight loss and a painless abdominal mass that on biopsy was diagnosed as a peripheral primitive neuroectodermal tumor/Ewing sarcoma (pPNET/EWS) of the soft tissue. The patient underwent chemotherapy followed by surgical resection of the tumor 5 months after diagnosis. The posttreatment residual viable tumor showed a morphologic appearance resembling a neuroblastoma. Interphase and metaphase fluorescent in situ hybridization (FISH) studies performed on the pretreatment and posttreatment samples showed the presence of a t(11;22) rearrangement resulting in EWSR1/FLI1 gene fusion consistent with pPNET/EWS in both specimens. This case is unusual in the sense of showing the typical gene fusion for pPNET/EWS both in the pretherapy sample with the typical morphological appearance of this tumor and in the posttherapy specimen showing neural differentiation suggestive of a neuroblastoma.

Extraosseous Ewing sarcoma with foci of neuroblastoma-like differentiation associated with EWSR1(Ewing sarcoma breakpoint region 1)/FLI1 translocation without prior chemotherapy

“…Her tumor presented a EWS-FLI1 fusion transcript. Lastly, Weissferdt et al [14] analyzed the retroperitoneal tumor of an 11-year-old girl, which, on prechemotherapy biopsy, was identified as PNET/ES with t (11,22) fusion, but then after treatment and ultimately after excision of the mass, it had the morphological appearance of a NB but maintained its PNET/ES t (11,22) fusion, thus still confirming the diagnosis of PNET/ES. Interestingly, in our case, the specific EWS-FLI1 translocation was found in both morphologically different malignant components, revealing the same cell origin.…”

Cervical ganglioneuroma in collision with a metastatic undifferentiated carcinoma

“…One consideration in the pathogenesis of this unusual pathological picture is the possibility of a primary neuroblastoma or PNET/Ewing sarcoma that has undergone neural-like differentiation secondary to chemotherapy following metastasis to a cervical lymph node. [ 11 12 13 ] However, the primary tumor lacked expression of neural markers or CD99 except for S-100 protein. The significance of S-100 protein expression is unknown; staining for S-100 protein is recognized to be nonspecific and may be observed in a variety of tumors of neuroectodermal origin.…”

CNS Tumor 22 Years after Spinal Neuroblastoma IV: Diagnostic Dilemma between Recurrence and Secondary Malignancy

“…Two years later the patient suffered from a diffusely infiltrating local recurrence, changing its imaging appearance as well as its immunohistochemical characteristics, now revealing disseminated positivity for NSE and NCAM. Moreover, independent of the change in immunohistochemical characteristics from the first to the second cranial metastasis, which could also be interpreted as a change induced by chemotherapy and irradiation [43, 44], the diagnostic importance of systemic metastases and chromosomal characteristics of neuroblastoma as well as the lack of PNET-specific translocations (EWS/FLI1 gene fusion) in both brain tumors led us to the final diagnosis of a very late relapse 22 years after initial stage IV spinal neuroblastoma.…”