case_images: PMC9911301_01
case_images: PET scan at baseline showing the progression at mediastinal lymph nodes.
case_images: fonc-13-1079034-g001.jpg
case_images: PMC9911301_01_fonc-13-1079034-g001.jpg
case_images: f1
case_images: Based on tumor's molecular characteristics, therapy with pembrolizumab was started with a partial response lasting for 28 months, when tumor progressed on mediastinal lymph nodes ( Figure 1 ).
case_images: (A) Computed tomography scan showing multiple bone lesions. (B) Bone scan showing no evidence of bone metastases.
case_images: fonc-13-1079034-g002.jpg
case_images: PMC9911301_01_fonc-13-1079034-g002.jpg
case_images: f2
case_images: The computed tomography (CT) scan performed 2 months following the beginning of therapy showed a partial response on lymph nodes with the appearance of multiple bone lesions, as reported in  Figure 2A , not revealed by the bone scan ( Figure 2B ).
case_images: (A) Hematoxylin and eosin staining of adenocarcinoma of the lung, TTF1+ associated with fibrosis (70%); (B) Giemsa eosinophilic infiltrate, as indicated by the arrows.
case_images: fonc-13-1079034-g003.jpg
case_images: PMC9911301_01_fonc-13-1079034-g003.jpg
case_images: f3
case_images: At BMB, a much prominent metastasis of adenocarcinoma (with the same histopathological and immunophenotypical features), embedded within prominent fibrosis (70% of biopsy volume) and eosinophils ( Figures 3A, B ) was disclosed.
case_images: PMC9911301_02
case_images: Timeline showing the clinical history of both patients.
case_images: fonc-13-1079034-g004.jpg
case_images: PMC9911301_02_fonc-13-1079034-g004.jpg
case_images: f4
case_images: Since July 2021, he developed hypereosinophilia (up to 8 x 109/L), as shown in  Figure 4 .