PMC8627308_01
Chest computed tomography images. (A and B) At the initiation of trastuzumab deruxtecan (T-DXd) treatment. Every lesion recurred rapidly. (C and D) Eleven days after T-DXd treatment. All lesions shrank in size in response to T-DXd treatment. (E and F) Six months after T-DXd treatment. All lesions remained shrunken in response to T-DXd treatment. Response of tumor was assessed partial response by RECIST Ver 1.1.
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However, rapid disease recurrence was observed with the progression of left lower lobe primary tumor, miliary lung metastasis, bilateral malignant pleural effusion, and appearance of carcinomatous lymphangitis on computed tomography (CT) scan (Figure 1). Moreover, lung metastasis and pleural effusion improved (Figure 1).
(A) Hematoxylin and eosin staining revealed malignant cells forming glandular duct structures in the transbronchial lung biopsy (TBB) specimen. (B) Malignant cells were strongly positive (3+) for human epidermal growth factor receptor 2 (HER2) based on immunohistochemical staining. Scale bar is 100microm.
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Immunohistochemical staining of TBB specimens, which was performed by a pathologist, revealed HER2 positivity (Figure 2).