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Preoperative brain imaging. A plain computed tomography (CT) scan showed a 20-mm high-density lesion in the left basal ganglia (A), a 25-mm mass located primarily within the right inferior frontal gyrus (B), and a 5-mm mass in the right frontal lobe facing the cerebral falx (C). In the magnetic resonance imaging (MRI), all lesions showed isointense on a T1-weighted image (T1WI) that was enhanced by gadolinium and hyperintense on a T2-weighted image (T2WI) (D-L). All lesions were associated with strong edematous alterations, especially in the right frontal lobe lesion (G-I).
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Plain CT scan of the head showed a 20-mm high-density lesion in the left basal ganglia (Fig. 1A), a 25-mm mass mainly located in the right inferior frontal gyrus (Fig. 1B), and a 5-mm mass in the right frontal lobe facing the cerebral falx (Fig. 1C). T1-weighted images (T1WI) and T2-weighted images (T2WI), whereas the right frontal lesions appeared isointense in T1WI and hyperintense in T2WI (Fig. 1D-I). The T1WI of all the lesions were enhanced by gadolinium (Fig. 1J-L). Edema was especially pronounced for the right frontal lobe lesion (Fig. 1G-I), which extended to the precentral gyrus and could have therefore caused the observed upper left limb paralysis.
PMC10101700_02
Macroscopic and microscopic findings from right frontal lesion. (A) Intraoperative photo shows a grayish, soft neoplastic, non-hemorrhagic lesion (arrow). Additional pathological results are visible in (B-F). (B) Hematoxylin-eosin stain, original magnification x400. We found tumor cells with well-defined cell borders and a morphology indicating epithelial origin. There is no melanin pigment. (C) p40 + CK14, original magnification x200, showing negative results. (D) S-100, original magnification x200, showing positive results. (E) HMB-45, original magnification x200, showing positive results. (F) Melan-A, original magnification x200, showing positive results.
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Tokyo, Japan). The lesion was grayish, soft neoplastic, and not hemorrhagic (Fig. 2A). The pathological examination of the frozen section was consistent with metastatic brain tumor, while in the histopathological examination, we found tumor cells with well-defined cell borders and a morphology suggestive of epithelial origin (Fig. 2B). AE1/3, CAM5.2, and p40 + CK14 (Fig. 2C) and positive for S-100, HMB-45, and Melan-A (Fig. 2D-F); these markers are characteristic of melanocytes, however, no melanin pigments were found in the hematoxylin & eosin staining.
Radiographic and microscopic findings from the left lymph node lesion. (A) The 18-F-fluorodeoxyglucose (FDG) positron emission tomography (PET)-CT (SUVmax 21.9) shows a 3-cm enlargement and high accumulation within the left axillary lymph node (arrow). (B-D) show pathological examination of the left lymph node lesion from fine-needle biopsy. (B) Hematoxylin-eosin stain, original magnification x400, showing epithelial-like tumor cells without melanin pigment. (C) S-100, original magnification x200, showing positive results. (D) HMB-45, original magnification x200, showing positive results.
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A whole-body positron emission tomography-CT (PET-CT) scan with the glucose analog 18-F-fluorodeoxyglucose (FDG) showed high accumulation (SUVmax 21.9) in the left axillary lymph node (Fig. 3A). Additional biopsy of the left axillary lymph node showed similar epithelial-like tumor cells without melanin pigment (Fig. 3B), and the IHC suggested metastasis of the melanoma (Fig. 3C and D).
Postoperative images. One year after surgery, we did not observe any recurrence of locally treated lesions in the left basal ganglia and in the right frontal lobe investigated via MRI (T1WI enhanced by gadolinium) (A-C). After temporary interruption of systemic treatment, two lesions appeared in similar MRI images of the right parietal lobe and left cingulate gyrus (D). FDG PET-CT at 1 year after the start of molecular-targeted therapy shows that the high accumulation in the left axillary lymph node has disappeared (E).
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Given that the patient was free of local recurrence when investigated with gadolinium-enhanced MRI at one year after surgery, we evaluated the antitumor effect as complete remission (CR) (Fig. 4A-C). Adverse Events (CTCAE, version 5.0, gammaGTP: upper limit of normalx5.27). Although the hepatic dysfunction improved within a month, the MRI revealed new lesions in the right parietal lobe and left cingulate gyrus (Fig. 4D) after 3 months of drug withdrawal. In the concomitant whole-body PET-CT with FDG, no new lesions were detected, indicating that the accumulation in the left axillary lymph node had disappeared (Fig. 4E).