Presentation
Right sixth nerve palsy for 3 days
Patient Data
Soft tissue mass centred in the right clivus superiorly causing bony destruction. The mass bulges into the prepontine cistern, extends into the right cavernous sinus and also extends into the posterior aspect of the sphenoid sinuses where there is rounded soft tissue density as well. The pituitary gland and stalk look normal though there is some erosion into the posterior wall of the sella turcica present. On transverse measurement, lesion size is approximately 2.7 x 1.3 cm.
IMPRESSION:
Skull base lesion centred in the clivus, causing bony destruction and likely invading the right cavernous sinus. Differential diagnosis includes metastatic disease, plasmacytoma, chordoma, intraosseous lymphoma. Follow-up MRI assessment is indicated.
An osteolytic solid, high T2 signal intensity, mildly heterogeneous, enhancing mass lesion is present involving the clivus as described on the recent CT. The lesion is adjacent to the medial and posterior aspects of right internal carotid artery in the posterior cavernous sinus region, extends into the posterior aspect of the right sphenoid sinus and protrudes slightly posteriorly into the pre-pontine cistern adjacent to the anterior aspect of basilar artery. The lesion involves the posterior wall of sella but it does not involve the pituitary.
IMPRESSION: An osteolytic lesion involving the clivus is present with differential diagnosis including chordoma, chondrosarcoma or metastasis. A lymphoma or plasmacytoma could also have this appearance in the appropriate clinical setting.
Pathology report
Final diagnosis: Biopsy, clival tumour - Positive for chordoma
Microscopic: This biopsy from the clival tumour shows a proliferation of cells with clear cytoplasm and small hyperchromatic nuclei. Most of the cells have the appearance of a single vacuolar space, however an occasional one does show multiple vacuoles suggestive of physaliferous cells. The differential diagnosis of this tumour includes chordoma as well as metastatic renal cell carcinoma of clear cell type and chondrosarcoma. I favour the diagnosis of chordoma based on the presence of physaliferous cells as well as the location of the tumour since the clivus is a typical site of origin for a chordoma. The other diagnosis, of course, must be considered. A panel of immunostains was performed with the following results: CK1-3 strongly positive, EMA strongly positive, CK7 negative, CK20 negative, CD10 negative, E-Cadherin negative, S100 negative. These results are somewhat equivocal. The cytokeratins and EMA are consistent with chordoma, however, the negative S100 and E- Cadherin are usually but not always positive in this tumour.
Specialist opinion: Unusual immunoprofile with repeated S100 negative as well as negative results for D2-40, CDX2, and TTF-1. Additional brachyury immunostaining was performed. The results were positive, confirming the diagnosis of chordoma.
Case Discussion
Chordoma of the clivus. Diagnosis confirmed via trans-sphenoid biopsy. Patient went on to have tumour debulking.