MDP Bone Scan: A Key Step in Assessment and Staging of a Rare Presentation of Ewing Sarcoma in a Young Adult Man

摘要

A Spanish speaking young man who presented with a painful supra-orbital head mass causing progressive diplopia and epistaxis. Initial clinical and radiological work-up suggested an esthesioneuroblastoma (i.e., olifactory neuroblastoma) with its associated good prognosis. However, further history (obtained through an interpreter) caused the primary physician to order a nuclear bone scan. The results from this scan dramatically changed the clinical approach, tumor work-up, diagnosis and treatment of this patient who was found to have an atypical metastatic Ewing sarcoma. Introduction Ewing sarcoma (ES) typically presents as a tumor originating in the diaphyseal marrow of the long and flat bones which spreads throughout the bone cortex to form a non-osteoid soft tissue mass. Most frequently ES affects Caucasian boys under the age of 15, with a prevalence of approximately 2-3 cases per 1 million population. It is a small blue cell tumor of the primitive neuroectodermal type. From 15 to 30% of cases present with metastatic disease although aggressive spread of this neoplasm to the head or skull is very rare [1]. This case report demonstrates the importance of nuclear medicine bone imaging in the evaluation of a young adult with an anterior skull base tumor, initially diagnosed as an olifactory neuroblastoma. The Tc-99m MDP bone scan strongly suggested a primary lower extremity ES with metastatic spread to the anterior skull base, calvarium and appendicular skeleton and confirmed histologically. Case Report A 19 year old Spanish speaking man presented to our ER with a one month history of a palpable, hard, right supraorbital facial mass, causing progressive worsening diplopia and “old blood” brown color epistaxis. The patient reported hitting his head and attributed the swelling to trauma. He denied fevers, loss of appetite, weakness or numbness of his extremities. A complicated, expansile extra-axial lesion, seen in the pre-surgical CT scan [Fig 1.], appeared to originate in the sinuses which involved both the inner and outer table of the calvarium.