PMC8720449_01
(a and b) Axial and sagittal post contrast T1-weighted images. A pineal region tumor had grown after combination chemotherapy using carboplatin and etoposide, with a maximum diameter of 46 mm. (c and d) Axial source images of preoperative three-dimensional computed tomography angiography (3D-CTA). Arrows (c) and a solid, open arrowhead (d) show the vein of Galen and the right and left internal cerebral vein, respectively; the left internal cerebral vein is passing through the tumor. (e and f) Reconstructed 3D-CTA images for preoperative planning indicate the left (e) and right (f) occipital transtentorial approaches, respectively.
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F1
However, the tumor had grown 1 month after (maximum diameter, 46 mm) [Figure 1a and b], for which the patient underwent surgical resection. Preoperative three-dimensional computed tomography angiography revealed that the right internal cerebral vein (ICV) and the vein of Galen had shifted to the right side, and the left ICV passed through the tumor [Figure 1c-f].
Axial and sagittal post contrast T1-weighted images. (a and b) The tumor was partially removed in the initial surgery by the left occipital transtentorial approach. (c and d) After surgery, whole-brain radiotherapy (26 Gy) and local radiotherapy (34 Gy) were performed concomitantly with temozolomide administration; however, the residual tumor enlarged. (e and f) Subsequently, the second surgery was performed using bilateral occipital transtentorial approach, and approximately 90% of the tumor volume was removed.
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The lower half of the left side of the tumor was removed [Figure 2a and b]. However, post treatment MRI revealed tumor regrowth (maximum diameter, 47 mm) [Figure 2c and d], and surgical removal was again performed using bilateral OTA. Postoperative MRI showed a removal rate of 90% [Figure 2e and f].
(a) 18F-fluorodeoxyglucose positron emission tomography 6 weeks after the second surgery showing high glucose metabolism in the residual tumor. (b) Post contrast T1-weighted images obtained 2 months after the end of maintenance chemotherapy (29 months after initial surgery) showing enlargement of the enhancing lesion. (c) However, 11C-methionine positron emission tomography demonstrated no abnormal metabolism. (d) Post contrast T1-weighted images reveals no recurrence under bevacizumab monotherapy 6 years after initial surgery.
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One month after discharge, 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) revealed high glucose metabolism in the residual tumor [Figure 3a], suggesting high tumor activity. MRI performed 2 months after the end of chemotherapy (29 months after the first surgery) again revealed an enlargement in the enhanced area [Figure 3b]. FDG-PET and 11C-methionine (Met) PET [Figure 3c] did not show any accumulation. Six years after the initial treatment, the tumor size remained stable [Figure 3d], and the patient has not encountered any problem in his student life.
Pathological and molecular findings of the present tumor. (a) Hematoxylin and eosin staining showing marked diffuse proliferation of the atypical astrocytic tumor cells. (b and c) Immunohistochemical staining showing that the tumor cells were positive for H3.3 K27M and negative for H3 K27me3. (d) Sequencing chromatogram, obtained using Sanger sequencing, showing K27M mutation in H3F3A (c. 83A>T) (arrowhead). (e) MGMT methylation-sensitive high-resolution melting (MSHRM) analysis showing two peaks of 0% (left) and 100% (right) methylated controls in the left panel. Two different peaks are obtained for the PCR product derived from the unmethylated and methylated templates. The right panel is from the sample of the present case demonstrating a peak of unmethylated DNA. Data were analyzed using the Tm Calling software module.
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Hematoxylin-eosin staining [Figure 4a] revealed marked proliferation of astrocytic tumor cells with nuclear atypia. Immunohistochemical staining was positive for H3.3 K27M [Figure 4b] and negative for H3 K27me3 [Figure 4c]. Sanger sequencing revealed K27M mutation in H3F3A (c.83A>T) [Figure 4d], and the MGMT gene promoter was unmethylated [Figure 4e].