What is non calcified pulmonary parenchymal nodule?

Definition:

- A focal area of pulmonary opacity <3 cm in size, on a CT scan, that consists entirely of uncalcified lung parenchyma, i.e., without an identifiable calcification.

- Most commonly, benign and may be caused by a variety of things including infection, scarring, atelectasis, and hamartoma.

- May occasionally be malignant. Further imaging and/or biopsy is sometimes needed to differentiate these from benign lung nodules.

Pathophysiology:

- Can be caused by a variety of things including hamartomas, inflammatory lesions (infections, sarcoidosis), neoplastic lesions, and miscellaneous lesions (vascular, developmental, traumatic).

- Most commonly are due to post-inflammatory processes including resolved infections (granuloma), interstitial fibrosis, and organizing pneumonia. May also occur in association with a variety of connective tissue diseases (e.g., rheumatoid arthritis, scleroderma, amyloidosis).

- Approximately half of lung nodules with diameters of 4-6 mm are hamartomas. Hamartomas are usually solitary, round or oval, well-circumscribed lesions with a "popcorn-like" appearance. They may contain fat and/or calcifications. However, many hamartomas are also noncalcified.

Clinical Significance:

- Most noncalcified lung nodules are benign, and no treatment is necessary.

- However, the diagnosis and management of pulmonary nodules can be complex.

- In certain cases, follow-up imaging is performed.

- If the nodule grows in size, further evaluation is necessary to determine a cause and recommend appropriate treatment.