case_images: PMC10663044_01
case_images: Histopathology for scalp primary tumour and metastatic lesions. a H&E stain of malignant glandular epithelium deep to the epidermis (x400 magnification). b CEA stain positive in eccrine glands (x100 magnification). c PAS following diastase stain positive in eccrine glands (x200 magnification). d Metastatic adenocarcinoma in the lung (x400 magnification). e Metastatic adenocarcinoma in the brain (x200 magnification).
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case_images: F1
case_images: The findings were most consistent with a primary pT1N0M0 DEA (Fig. 1a-c). Histopathological review of both the lung and brain specimens demonstrated metastatic adenocarcinoma, morphologically similar to his previously resected scalp DEA (Fig. 1d, e).
case_images: Radiological evidence of distant metastasis on MRI brain demonstrating right pontine lesion (a), and PET-CT scan demonstrating PET-avid left-sided pulmonary lesion (b). PET, positron emission tomography; MRI, magnetic resonance imaging.
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case_images: F2
case_images: November 2020, physical examination demonstrated bilateral horizontal nystagmus, right-sided dysmetria and dysdiadochokinesis, and gait ataxia, with otherwise normal cranial nerve, upper limb, and lower limb neurological examinations. Neuroimaging revealed a solitary 25 mm peripherally enhancing cystic lesion of the right pons, with moderate surrounding oedema and mass effect, without significant midline shift (Fig. 2a). Further imaging, including a staging fluorodeoxyglucose positron emission tomography-computed tomography scan showed two left-sided pulmonary lesions (45 mm left lower lobe, 12 mm left lingula) and ipsilateral hilar lymphadenopathy (Fig. 2b).
case_images: CT of the chest in axial (a, b) and coronal slices (c, d): prior to immunotherapy (a, c); and following 21 months of immunotherapy, demonstrating radiological response of the lung metastases and hilar lymphadenopathy to pembrolizumab (b, d). CT, computed tomography.
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case_images: F3
case_images: At the time of writing, the patient has completed 21 months of pembrolizumab with a significant radiological response of lung metastases and hilar lymphadenopathy (Fig. 3), and nil evidence of metastatic disease at other sites.
case_images: Timeline of events of case presentation.
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case_images: F4
case_images: A timeline of the events of the case is depicted in Figure 4.