In this report 14 males and 5 females aged from 41 to 85 years (mean age 60.4 years) suffering from clival chordomas were included with histological confirmation at the Department of Neurosurgery, Kohnan Hospital between March 2006 and July 2019. The most common initial symptom was diplopia in 6 patients owing to cranial nerve palsy, but 2 patients owing to optic nerve dysfunction and 1 patient owing to spontaneous cerebrospinal fluid leakage (clival erosion with no visible tumor). Overall 8 patients were asymptomatic and the tumors were detected by prophylactic brain scans at each checkup. Initial treatments were applied for 17 patients; however, the remaining 2 patients had suffered from re-growth after pleural tumor removal and radiation therapy (Table 1). All of the tumors extended along the clivus; 8 patients experienced extra-arachnoidal localization, and the remaining 11 experienced tumor extension into the subarachnoid spaces. The patients were initially treated with maximal tumor removal by the extended transsphenoidal approach with simultaneous removal of the surrounding bone cortex and bone marrow as far as possible within the technical range of skull base repair. When gross total removal was achieved prophylactic irradiation was not performed, and patients were simply observed at 6-months intervals. If tumor remnants were visualized, the gamma knife was stood by until the skull base regeneration was accomplished (3 months after the operation) and applied. When tumor recurrence was confirmed, gamma knife surgery was subsequently applied to the visualized tumor bulk; this occurred in all patients except for one female patient (case 16), who was treated with postoperative fractionated irradiation because of her older age (85 years old). All the patients were followed up though out their clinical course with 9 to 224 months of follow up (mean 85.4 months).
Table 1
Preoperative clinical profile
Case | Age Ranges | Sex | Tumor volume (ml) | Maximum diameter (mm) | Initial symptom |
1 | 61–70 | F | 15.1 | 39 | 6 nerve palsy |
2 | 41^50 | M | 0.73 | 12 | brain checkup |
3 | 51–60 | M | 36 | 50 | 1 TO, 3GK |
4 | 61–70 | M | 12.7 | 40 | 6 nerve palsy |
5 | 51–60 | M | 14.4 | 32 | incidental |
6 | 41–50 | M | 9.8 | 39 | 1 removal, 1 FR |
7 | 61–70 | M | 26.4 | 50 | nasal congestion |
8 | 41–50 | M | 0.98 | 15 | incidental |
9 | 51–60 | M | Not visible | Not visible | CSF leakage |
10 | 41–50 | M | 11.7 | 30 | brain checkup |
11 | 71–80 | M | 2.52 | 28 | 3,4 nerve palsy |
12 | 71–80 | M | 5.13 | 27 | 6 nerve palsy |
13 | 61–70 | M | 3.4 | 20 | brain checkup |
14 | 61–70 | F | 12.8 | 41 | 6 nerve palsy |
15 | 51–60 | F | 2.76 | 23 | brain checkup |
16 | 81–90 | F | 17.9 | 42 | unilateral blindness |
17 | 51–60 | M | 68.5 | 52 | bitemporal hemianopsia |
18 | 51–60 | F | 66.5 | 63 | 3,6 nerve palsy |
19 | 51–60 | M | 0.17 | 8 | brain checkup |
All patients underwent axial, coronal and sagittal T1and T2-weighted magnetic resonance (MR) imaging with and without contrast medium (Signa Horizon, General Electric, Milwaukee, WI; 3.0 T system) and bone image computed tomography (CT) (Discovery CT 750 HD, General Electric) preoperatively, just after the operation. Follow-up MR imaging was performed at 6-month intervals after the operation (1.5 T system; Magnetom, Siemens AG, Erlangen, Germany). Gross total removal was defined as an absence of visible tumor bulk on both intraoperative findings and postoperative MR imaging.
The surgical specimens were immediately fixed for histological and immunohistochemical examinations with 10% buffered formalin, then embedded in paraffin, and serial sections were cut to 3-µm thickness. Hematoxylin and eosin, and periodic acid-Schiff staining were performed in all cases. The avidin-biotin-peroxidase complex method was applied for immunohistochemical staining and cell proliferation was assessed for Ki-67 (MIB-1, Dako, 1:100). Immunohistochemical positive cells were counted within at least 1000 background cells in three high power visual fields including the hot spot and other fields, and then indicated as a percentage. Positive controls used normal lymph nodes for Ki-67. Statistical comparisons were made using Statmate 5 software (ATMS Co., Ltd., Tokyo, Japan), and P values of less than 0.05 were regarded as significant.
The patients were informed preoperatively of the salvage treatment protocol and the study design was approved by the Ethical Committee of Kohnan Hospital 2020.