Case
Ahealthy 30-year old man presented to the emergency department with facial trauma after an assault. Physical examination was notable for tenderness over the nasal bones. No neurologic deficits were noted. Computed tomography (CT) scan of the head without contrast revealed nasal bone fractures and an incidental 7-mm tissue density within the posterior aspect of the left sphenoid sinus (Figure 1A) with an apparent dehiscence of the posterior wall and possible communication with the intracranial extra-axial spaces and brain parenchyma. A magnetic resonance imaging scan with contrast was recommended to further characterize the lesion which showed a transosseous T1 dark, T2 bright multilobulated mass measuring 2.1 × 1.4 × 1.3 cm with heterogeneous enhancement on postcontrast imaging extending into the sphenoid sinus. An endoscopic transnasal approach was used to obtain a tissue biopsy specimen. Pathological analysis revealed sheets of neoplastic, vacuolated, “soap bubble–like” cells with a myxoid background (Figure 1B).
Figure 1.
A, Sagittal computed tomography (CT) scan showing 7 mm tissue density within the posterior aspect of the left sphenoid sinus. B, Sheets of neoplastic, vacuolated, physaliphorous cells with a myxoid background (original magnification ×40).
What Is Your Diagnosis?
- Lipoma
- Chordoma
- Ecchordosis physalsiphora
- Chondrosarcoma
Discussion
Diagnosis
B. Chordoma
Chordomas are slow-growing tumors arising from the embryologic notochord. Due to their origins, these tumors occur most often along the axial skeleton with equal distribution in the skull base (32.0%), mobile spine (32.8%), and sacrum (29.2%). Mean age of occurrence is 36.9 years.1,2
Grossly, chordomas are lobulated, gelatinous, gray tumors well delineated from the surrounding tissue. Microscopically, chordomas consist of large, eosinophilic cells with multiple, round, clear vacuoles in a basophilic myxoid stroma. These vacuoles are classically referred to as physaliphorous or having a “soap-bubble” appearance (from the Greek “bubble-bearing”) (Figure 2). Vacuoles may coalesce and be mistaken for mature adipocytes. The World Health Organization recognizes 3 distinct variants of chordomas: conventional, chondroid, and dedifferentiated. Conventional chordomas are primarily composed of nests or trabeculae of eosinophilic cells with multiple clear, round vacuoles. Chondroid chordomas consist of areas resembling conventional chordomas and areas of chondroid differentiation resembling low-grade chondrosarcomas. Dedifferentiated chordomas contain high-grade sarcomatous areas and have a worse prognosis. Immunohistochemically, chordomas will stain with cytokeratin, epithelial membrane antigen, and S-100. Unlike histologic mimics, all 3 variants of chordomas will display nuclear brachyury staining with a high specificity (89.7%-100%).1-4
While the majority of these tumors are histologically benign, they are locally invasive with poor long-term prognosis. Five-year survival rates of skull-based chordomas with current treatment regimens is 50% to 80% with 10-year and 20-year survival dropping to 35% to 40% and 13%, respectively. Recurrence rates can be as high as 51% with surgical resection. Clinical parameters leading to increased recurrence rates include male sex, subtotal resection, and tumors located in the lower third of the clivus. Metastatic potential varies with tumor type and ranges from 10% to 18%.2,5,6
Most common clinical presentations of skull-base chordomas are abducens palsy, headache, and lower cranial nerve palsies. Radiographs of skull chordomas classically show an expansile, lytic lesion of the clivus with periosteal elevation. On magnetic resonance imaging, chordomas are hypointense on T1-weighted and hyperintense on T2-weighted images, with moderate to avid contrast enhancement. Negative predictive factors for survival include female sex, tumor necrosis prior to radiation therapy, and tumor volume greater than 70 mL. While location and extent of progression factor into treatment options, the current recommendations include gross total resection and postoperative radiation therapy.6,7
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Article Information
Published Online: July 3, 2019. doi:10.1001/jamaoto.2019.1662
Conflict of Interest Disclosures: None reported.
Additional Contributions: We thank the patient for granting permission to publish this information.
Additional Information: The authors are military service members, and this work was prepared as part of official duties. Title 17, US Code §105, provides that copyright protection under this title is not available for any work of the US government. Title 17, US Code §101, defines a US government work as a work prepared by a military service member or employee of the US government as part of that person’s official duties. No funding was obtained for this study.
References
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