Primary Ewing's sarcoma of the sinonasal tract, eroding the ethmoid and sphenoid sinus with intracranial extension: A rare case report

Abstract

Ewing's sarcoma (ES) is an aggressive tumour that may present with skeletal and extraskeletal forms. The extraskeletal form is rarely encountered in the head and neck region and is extremely rare in the sinonasal tract. This is the case report of a ES of the ethmoid sinus with intracranial and orbital extension in a 33-year-old male patient who presented with anosmia, epistaxis, reduction of visual acuity in the left eye and headache. On otorhinolaryngological clinical examination and biopsy via flexible endoscope, the lesion was misdiagnosed as ethmoid sinus carcinoma. The subsequent magnetic resonance imaging (MRI) of the brain revealed a large mass (6×7 cm) eroding the ethmoid and sphenoid sinuses, extending beyond the orbits and occupying the anterior cranial fossa with a maximum extension of ~5 cm. The patient underwent surgical resection and the microscopic examination of the specimen established the diagnosis of ES (immunohistochemically positive for CD99, neuron-specific enolase, CD56, synaptophysin, pancytokeratin, low-molecular weight cytokeratins and vimentin. The periodic acid Schiff stain exhibited strong intracytoplasmic block positivity and fluorescence in situ hybridization revealed a t(22;11) translocation. First-line chemotherapy was administered for 3 cycles; however, on restaging MRI, local disease progression was diagnosed. The patient received radiotherapy and second-line chemotherapy for 6 cycles. At 15 months after the diagnosis, the patient remains recurrence-free and maintains a good functional status and quality of life.

Keywords: Ewing's sarcoma; chemotherapy; intracranial extension; magnetic resonance imaging; sinonasal tract.

Figure 1.

Preoperative magnetic resonance imaging, (A) sagittal and (B) coronal, spin-echo T1-weighted images, following intravenous gadolinium administration. The sequences revealed the presence of solid tissue with inhomogeneous enhancement eroding the ethmoid and sphenoid sinuses, infiltrating the upper portion of the nasal septum and extending to the medial wall of the orbits, displacing and compressing the frontal lobes.

Figure 2.

Immunostaining of tumour samples. The tumour is composed of broad sheets of small round cells with scant clear cytoplasm and coarse chromatin. Hematoxylin and eosin staining, magnification (A) x200; (B) x400. (C) The cytoplasm is typically periodic acid Schiff-positive, as it contains glycogen (magnification, x400). The tumour has a high mitotic index and the tumour cells are diffusely positive for (D) CD99 (magnification, x400) and (E) low-molecular weight cytokeratin (immunoperoxidase staining; magnification, x200).

Figure 3.

Postoperative magnetic resonance imaging. (A) Turbo spin-echo T2-weighted coronal sequence 11 months after the diagnosis and (B) T1-weighted axial sequence 14 months after the diagnosis. The images show the surgical cavity with inflammatory thickening and no signs of recurrence; (B) also shows persistent reduced inflammatory thickening, with no signs of recurrence.