PMC7472920_01
CT scan before the initiation of osimertinib showed a primary tumor in left upper and lower lung and lymphadenopathy of hilar and mediastinum.
gr1.jpg
PMC7472920_01_gr1.jpg
fig1
Lung computed tomography (CT) scan showed left upper lung tumor and hilar and mediastinal lymph node enlargement (Fig. 1).
CT scan after two months of osimertinib treatment. (A) The primary tumor can be seen to be shrinking. (B) The upper panel shows left axillary lymph node enlargement. The middle and bottom panels show paraaortic lymphadenopathy (arrow) and dirty fat signs in the retroperitoneal region (arrowheads).
gr2.jpg
PMC7472920_01_gr2.jpg
fig2
Although the size of the primary tumor clearly reduced (Fig. 2A), multiple lymph nodes including the left axillary around the abdominal artery were enlarged, and the fat around the aorta to pelvic area was cloudy (Fig. 2B).
(A) Ultrasound image of he left axilla lymph node. (B) ~ (E) Histopathological findings of the left axilla lymph node biopsy specimen. (B) Hematoxylin and eosin (HE) stain; x 40. (C) HE stain; x 400. Bundled fiber findings. (D) HE stain; x 400. Dense infiltration of lymphocytes and plasma cells. The arrow indicates plasma cells. (E) Immunohistochemical staining for IgG, x 400. (F) IgG4, x 400. IgG4-positive plasma cells >30/HPF, IgG4/IgG cell ratio was approximately 50%.
gr3.jpg
PMC7472920_01_gr3.jpg
fig3
Histological analysis showed infiltration of lymphocytes and plasma cells with fibrosis (Fig. 3C and D). Immunohistochemistry indicated IgG4-positive plasma cell infiltration with an over 30 cell count per high-power visual field (HPF) and an IgG4 to IgG ratio of more than 40% (Fig. 3E and F).
CT scan after prednisolone administration. The tumor size slightly reduced, and the axillary lymph node was completely diminished.
gr4.jpg
PMC7472920_01_gr4.jpg
fig4
Prednisolone (0.6 mg/kg/day) was administered, and improvement of his symptoms and multiple lymphadenopathies was observed (Fig. 4).