case_images: PMC11829293_01
case_images: (a) The early postoperative axial post-contrast T1-weighted image showed a peripherally reactive enhancing resection cavity without tumor. (b) At the 3-month follow-up after starting immunotherapy, the T1-weighted image showed increased parenchymal edema around the resection cavity, new irregular contrast enhancement at the cavity level, there is no evidence of increased perfusion on the cerebral blood volume (CBV) map, indicating pseudoprogression. (Hypoperfusion could not be evaluated as a definite sign of recurrence). (c) At the 6-month follow-up, enhancement was visible within the cavity without peripheral edema. After 6 weeks, there is no difference in the findings except for the regression of the millimetric restricted diffusion foci observed in the immediate anterior-superior neighbourhood of the resection cavity. (d) At the 9-month follow-up, the enhancing part within the cavity was slightly highlighted. (e) At 24 months, there was significant regression of abnormal contrast enhancement within the central portion of the surgical bed.
case_images: 10.1177_10732748251322072-fig1.jpg
case_images: PMC11829293_01_10.1177_10732748251322072-fig1.jpg
case_images: fig1-10732748251322072
case_images: Due to the progression detected in the MRI scan following the second cycle of temozolamide treatment, a re-surgery was performed (Figure 1(A)), and the patient was initiated on pembrolizumab treatment. A cranial MRI performed during the third month of the patient's pembrolizumab treatment showed increased parenchymal edema around the resection cavity, dural scarring and thickening at the level of the resection cavity, and new irregular contrast enhancement at the level at the cavity (hypoperfusion could not be assessed as a definite sign of recurrence) (Figure 1(B)). The MRI scan taken six months after pembrolizumab initiation (Figure 1(C)) showed regression of the millimetric restricted diffusion foci, ruling out true progression. After completing 10 cycles of treatment, a period of treatment-free monitoring commenced (Figure 1(D) and ((E))).
case_images: PMC11829293_02
case_images: (a) After the first cranial surgery, the post-contrast axial T1-weighted image showed the resection cavity without tumor. (b) At the 9-month follow-up after starting immunotherapy, a prominent peripheral enhancement was observed in the resection cavity with mild peripheral oedema. (c) At the 18-month follow-up, a markedly enhancing mass-like lesion was seen in the resection cavity with peripheral edema. There is no evidence of perfusion. (d) There was a markedly increased enhancing mass-like lesion within the surgical bed with prominent peripheral edema.
case_images: 10.1177_10732748251322072-fig2.jpg
case_images: PMC11829293_02_10.1177_10732748251322072-fig2.jpg
case_images: fig2-10732748251322072
case_images: Following cranial surgery (Figure 2(A)), further radiotherapy was administered. When re-evaluated using the iRANO criteria, progression was favored over pseudoprogression based on clinical findings and imaging (Figure 2(C) and ((D))).
case_images: PMC11829293_03
case_images: (a) Immediately after the second cranial surgery, the post-contrast axial T1-weighted image showed a peripherally reactive enhancing resection cavity. (b) At the 6-month follow-up after the start of immunotherapy, compared with the postoperative MRI, there is an increase in the size of the expansile enhancing lesion in the left temporal follow-up, regression in the interval process in the areas of increased perfusion adjacent to the left lateral ventricular wall compared with the previous examination, and a stable peripheral FLAIR signal. Taken together with the slight increase in size of the lateral peripheral enhancing nodular focus, the stability of the FLAIR signal, and the decrease in areas of high perfusion adjacent to the ventricle at the previous examination, this may be due to possible treatment-related fibrotic changes in the patient undergoing immunotherapy treatment, and close follow-up of this area will be useful. (c) In the left posterior temporal lobe, contrast enhancement increased and the lesion grew in the interim period, and there was growth of the mass component extending under the scalp on the left. The findings were evaluated in favor of tumor progression.
case_images: 10.1177_10732748251322072-fig3.jpg
case_images: PMC11829293_03_10.1177_10732748251322072-fig3.jpg
case_images: fig3-10732748251322072
case_images: The patient underwent a second cranial surgical procedure due to progressive disease (Figure 3(A)), and pembrolizumab treatment was initiated. During the 6-month follow-up after starting immunotherapy, postoperative MRI showed an increase in the size of the expansile enhancing lesion in the left temporal region (Figure 3(B)). After six months of follow-up, the patient underwent surgery due to increased intracranial pressure (Figure 3(C)).