Batra et al listed features of a pulmonary parenchymal nodule seen on a chest X-ray that would help identify it as benign or malignant.
Indeterminate or Noncontributory
< 2 cm
2 – 3 cm
> 3 cm
benign pattern (see below)
none, or eccentric
stable for 2 years
increasing in size
< 30 days or 490 days
30 – 490 days
thin walls (< 4 mm) and/or air-fluid level
may be cavitated
nearby satellite lesions
Calcification patterns seen in benign lesions:
(1) granulomas: dense central, diffuse or laminated
(2) hamartoma: "popcorn"
Calcifications in malignant tumors:
(1) Eccentric calcifications may be present if the tumor engulfs a calcified granuloma.
(2) Some primary lung carcinomas may show subtle calcifications.
(3) Some metastatic tumors (osteogenic sarcoma, thyroid carcinoma, breast, GI tract) may calcify.
To calculate the doubling time:
doubling time in days =
= ((initial diameter in cm) * (days between films)) / ((second diameter in cm) – (initial diameter in cm))
which can be calculated from the straight line equation, with:
• intercept = (initial diameter)
• slope = ((second diameter) – (initial diameter)) / (days between)
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Specialty: Pulmonology, Hematology Oncology