Purpose: For decades, the CT diagnosis of pulmonary hamartoma (PH) has been based on the presence of popcorn calcifications or fat (-40 to -120HU) limited to a smooth
Materials and Methods: We retrospectively assessed the CT scans of histologically confirmed: PH (histPH), pulmonary metastases and primary lung cancers as well as PH diagnosed by CT (CTPH). Their size, volume, average, minimum and maximum HU were assessed using an ROI of at least 8 pixels, placed in the lowest attenuation region of the nodule.
Results: There were 52 histPH, 41 metastases, 49 primary lung cancers, and 34 CTPH. PH average size and volume were 14.5mm and 2270.2mm3 and that of malignancies 26.5mm and 22,031mm3. Popcorn calcifications were seen in 2 (4%) histPH, 11 (32%) CTPH and in none of the malignant lesions. The average HU for histPH, CTPH, metastases, and primary lung cancers were: 3.99, -10.97, 25.53, 38.61 respectively. Of the malignant lesions, only 4 had an average of
Conclusion: By increasing the threshold for identification of fat in PH to –20 unnecessary surgical intervention may be prevented without misdiagnosing cancer as benign.
