This previously healthy 13-year-old female presented with a 2-month history of a slow-growing mass in the left temporal region. Review of systems was unremarkable. CT scan and MRI scan were obtained at an outside institution for further evaluation of the mass.
Vaseem Iqbal, MD (Diagnostic Radiologist)
CT scan reveals evidence of an inhomogeneously enhancing soft-tissue mass arising from the infratemporal fossa on the left. The lesion is involving the soft tissues superior to the zygomatic arch and adjacent to the left temporal bone. Examination of bone windows reveals bone erosion of the anterolateral aspect of the temporal bone, which extends to the articular cortex of the left temporal mandibular joint (Fig. 1). MRI examination demonstrates a soft-tissue mass lateral to the temporal bone in the suprazygomatic portion of the left face (Fig. 2). The lesion measures 3.5 cm by 2.5 cm and involves the left temporalis muscle. There is no intracranial extension or meningeal involvement.
Differential diagnosis would include lymphoma, rhabdomyosarcoma, and Ewing sarcoma. Infection or other benign disease such as fibromatosis should also be considered. The epicenter of this mass is in the soft tissues of the infratemporal fossa. Although there is some bone involvement, it is minimal and unilateral. There is no extension medially toward the mandibular condyle. However, in the case of Ewing sarcoma, osseous and extraosseous lesions can have similar appearance, and the distinction can be difficult [1].
Dr. Smith. The patient underwent incisional biopsy of the mass at an outside hospital before being referred to our institution. The surgery was complicated by bleeding and was thus aborted during an attempt at complete re-