case_images: PMC11345153_01
case_images: In (A) (first brain study from April 2022), the axial T1 sequence after the administration of IV gadolinium shows a contrast-enhancing intra-axial pontine focal lesion with foci of central necrosis and expansion of the brainstem, compatible with M1. In (B) (obtained in February 2023, 9 months after the completion of radiotherapy), a reduction in the diameters and degree of uptake of the intra-axial pontine lesion can be seen. The appearance of leptomeningeal uptake is also seen on the pontine surface and cisternal tract of the III nerve bilaterally. In (C) (obtained in July 2023, after eight cycles of SG), a notable progressive reduction of the pontine focal lesion and a decrease in leptomeningeal uptake on both the pontine surface and in the III cranial nerve can be seen.
case_images: fonc-14-1378248-g001.jpg
case_images: PMC11345153_01_fonc-14-1378248-g001.jpg
case_images: f1
case_images: A cranial MRI showed a single brainstem lesion and was referred to our center for a second opinion ( Figure 1A ). A Positron emission tomography-computed tomography (PET-CT) was performed and detected two nodules in the mastectomy site (of 7 mm and 4 mm), confirmed with an ultrasound-guided biopsy as TNBC, PD-L1 negative by both Ventana SP263 and CPS score. The pontine metastasis maintained an excellent control 9 months after hSRT (11 mm x 8 mm x 9 mm, - 95%) ( Figure 1B ). D3 level, suggesting tumor progression ( Figures 1C ,  2C ). Diplopia and lower limb weakness reappeared a few days after, and treatment was changed to carboplatin AUC5 plus gemcitabine.
case_images: In (A) (first spine study in February 2023), the sagittal spine T1 sequence after IV gadolinium administration shows extensive leptomeningeal uptake in the roots of the cauda equina and the surface of the spinal cord, which is compatible with meningeal carcinomatosis. In (B) (obtained in April 2023), a moderate decrease in generalized leptomeningeal uptake is seen. In (C) (obtained in July 2023), a marked decrease in diffuse leptomeningeal uptake in the cauda equine can be seen. However, a small focal lesion on the surface of the spinal cord at the high dorsal levels is new.
case_images: fonc-14-1378248-g002.jpg
case_images: PMC11345153_01_fonc-14-1378248-g002.jpg
case_images: f2
case_images: Spinal MRI performed for diagnostic and LC extension showed diffuse and extensive signs of leptomeningeal carcinomatosis, with perimedullary enhancement at the cervical and dorsal spine, as well as conus medullaris and cauda equina ( Figure 2A ). MRI showed partial response with a decrease, in contrast, uptake mostly in the roots of the cauda equina and the surface of the conus medullaris with improvement of the thickening and irregularity seen in the previous study. Moreover, meningeal uptake on the surface of the cord in the rest of its extension, dorsal and cervical, showed a practical resolution ( Figure 2B ). D3 level, suggesting tumor progression ( Figures 1C ,  2C ). Diplopia and lower limb weakness reappeared a few days after, and treatment was changed to carboplatin AUC5 plus gemcitabine.