PMC8606665_01
Radiological examination at initial visit. (A, B) Contrast-enhanced CT scan of the abdomen showing a malignant mass in the left kidney. (C) Chest CT scan showing metastatic nodules in the right lower lung. (D) Whole body bone scan showing abnormal T12 vertebration. CT, computed tomography.
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Contrast-enhanced computed tomography (CT) revealed the presence of a malignant mass (5.2 cm x 4.3 cm) ( Figures 1A, B ). Chest CT revealed multiple nodules in the right lower lung, indicating metastasis ( Figure 1C ). Whole-body bone scanning by emission CT suggested vertebral (T12) metastasis ( Figure 1D ).
Hematoxylin and eosin (HE) staining and immunohistochemical staining of the renal tumor (x200): (A) HE staining, (B) PAX8 (positive), (C) p63 (negative), (D) CD10(negative), (E) vinculin (positive) and (F) PD-L1(positive). PAX8, paired box 8; PD-L1, programmed cell death 1 ligand 1.
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Thus, cytoreductive nephrectomy was recommended, and pathological examination confirmed CDC ( Figure 2A ). Immunohistochemistry was used to examine the presence of several key markers: paired box 8-negative (PAX8; positive), p63 (negative), CD10 (negative), and vinculin (positive) ( Figures 2B-E ). Immunohistochemistry was positive for programmed cell death 1 ligand 1 (PD-L1) ( Figure 2F ).
Chest and spinal CT imaging manifestations after treatment. (A) First diagnosis. (B) After one cycle of pazopanib and camrelizumab. (C) Discontinuation of camrelizumab and monotherapy involving pazopanib for 5 months. (D) Three months after the combination treatment of axitinib and sintilimab. (E) Fourteen months after the combination treatment of axitinib and sintilimab. CT, computed tomography.
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However, chest CT showed remarkable shrinkage of the metastases, indicating a partial response ( Figures 3A, B ). CT showed malignant pleural effusion and pleural metastasis ( Figure 3C ); this was confirmed by the cytological examination of pleural effusion. Considering the response of the patient to the previous combination strategy, axitinib (5 mg, per os, twice daily) and the PD-1 monoclonal antibody sintilimab (200 mg, intravenous gtt, once every 3 weeks) were duly administered. Chest CT revealed a marked reduction of pleural effusion ( Figure 3D ). Chest and abdomen CT did not reveal the presence of abnormal lesions ( Figure 3E ) and demonstrated improvement in the osteogenic structure at the site of vertebral metastasis ( Figure 3E ).
Timeline of treatment. CDC, collecting duct carcinoma; met., metastasis; PD, progressive disease; PR, partial response.
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Thereafter, the patient remained tumor-free for >14 months after receiving the combination therapy ( Figure 4 ).