Fig. 5

Pathological findings of lung lesions in three patients with S-DiPO. (a) Medium-power view of a specimen from a patient with S-DiPO (Patient 7). Multiple foci of bone (white stars, mixed type, maximum size-G2, and bone marrow-G3) and a CiOP lesion (black star, CiOP-G2) are observed. (b) Notable OP findings (yellow stars, OP-G3) close to CiOP lesions. High-magnification view of the area indicated by the black rectangle in (a). (c) Low-power view of a specimen from a patient with S-DiPO (Patient 24). An ossified lesion (white stars, maximum size-G1, bone marrow-G0) with subpleural fibrosis (red stars, subpleural fibrosis-G3) is shown. Inset; High magnification view of the area in the black rectangle in (c). (d) Middle power view of a specimen from a patient with S-DiPO (Patient 12). (d, e) Various phases of the lesion, including OP (yellow stars, OP-G3), CiOP (black stars, CiOP-G1), and ossification (white stars, bone marrow-G0), observed in close proximity. e: High-magnification view of the black rectangle in (d). Scale bars: 2 mm (c), 1 mm (a), and 0.2 mm (b, d, and e). CiOP cicatricial organising pneumonia; DiPO, diffuse pulmonary ossification; G, grade; OP, organising pneumonia.