An unusual retroperitoneal tumour mimicking adrenal pheochromocytoma

Abstract

ttp://dx.doi.org/10.1016/j.dld.2015.06.009 590-8658/© 2015 Published by Elsevier Ltd on behalf of Editrice Gastroenterologica Ital norepinephrine (964 ng/L). She underwent retroperitoneal tumour resection. Microscopic examination revealed sheets of uniform small, blue, round to oval cells with scant cytoplasm, hyperchromatic chromatin, and inconspicuous nucleoli (Fig. 1B and C). Immunohistochemical analysis showed tumour cells positive for CD99 (Fig. 1D). Fluorescence in situ hybridization further confirmed the diagnosis of Ewing sarcoma/primitive neuroectodermal tumor (ES/PNET). She received a cycle of systemic chemotherapy including pirarubicin, cyclophosphamide and etoposide two weeks after surgery, however she died of multiple metastases 12 months later. ES/PNET is a family of highly malignant tumours composed of small round cells that occurs predominantly in bone and soft tissues of children and young adults. Our case is unique in its rarely retroperitoneal location as previous extranskeletal ES/PNET primarily involved paravertebral locations and the genitourinary tract. Moreover, it mimicked adrenal pheochromocytoma due to the significant rise in plasmatic norepinephrine. Because surgical resection alone often results in rapid recurrence and metastasis, multimodal therapy, combining chemotherapy with local control treatment (surgery and radiation therapy), should be used to improve prognosis [1].