PMC10114023_01
Initial treatment: spiculated parenchymal-based nodule in posterior right upper lobe enlarging on CT thorax seen with lung window (a) and bone preset (b). c SABR was started after this CT showed mass enlargement to 1.5 x 1.1 x 2.5 cm with radiotherapy isodose lines in centigray from SABR treatment.
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F1
Over 9 months of surveillance, CTs showed growth to 15 mm as shown in Figure 1. Given the high probability of malignancy and elevated risks of surgical excision given her respiratory function, the patient received SABR treatment with 54 Gy in 3 fractions, every other day (shown in Fig. 1). CT scan exhibited the following concerning changes as reported by radiology: "interval change in the posterior right 4th and 5th ribs with expansion of the marrow cavity, associated with increased density particularly in the 5th rib and periosteal break in the 4th rib. Some of these appearances could represent radiation sclerosis, but expansion of the medulla is unusual and is of concern for possible malignant infiltration" (shown in Fig. 2). Clinically, the CT changes corresponded to the high-dose radiation treatment volume (shown in Fig. 1) and were suspected to be benign radiation-related post-treatment changes.
Findings on surveillance CT: CT thorax on June 7, 2019, revealed interval change in the posterior right 4th and 5th ribs with expansion of the marrow cavity (a), associated with increased density particularly in the 5th rib image 62 (b) and periosteal break in the 4th rib image 55 (c).
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F2
CT scan exhibited the following concerning changes as reported by radiology: "interval change in the posterior right 4th and 5th ribs with expansion of the marrow cavity, associated with increased density particularly in the 5th rib and periosteal break in the 4th rib. Some of these appearances could represent radiation sclerosis, but expansion of the medulla is unusual and is of concern for possible malignant infiltration" (shown in Fig. 2). Clinically, the CT changes corresponded to the high-dose radiation treatment volume (shown in Fig. 1) and were suspected to be benign radiation-related post-treatment changes.
MR chest: bone on September 9, 2019, showed abnormal signal changes involving the right posterior fourth and fifth ribs with what appear to be healing fractures using T1 (a) and T2 (b).
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F3
MRI revealed that 4th and 5th rib lesions corresponded to healing fractures (shown in Fig. 3).