A chest CT performed for an incidental finding in a 45-year-old woman reveals a well-circumscribed 2 cm peripheral nodule containing fat attenuation and popcorn-like calcification. Histology would show mature cartilage, fat, and smooth muscle in a disorganized admixture indigenous to the lung. This lesion is best classified as a:

• A Hamartoma ✓
• B Choristoma
• C Teratoma
• D Hamartochondroma of germ cell origin

Explanation

B hamartoma is a benign, disorganized overgrowth of tissue elements normally found at that anatomical site, and pulmonary hamartoma with cartilage, fat, and smooth muscle is the prototype. B choristoma is normal tissue located where it should not exist, such as gastric mucosa in the Meckel diverticulum or adrenal rest under the renal capsule. Teratomas contain derivatives of all three germ layers and arise mainly in gonadal or midline sites.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.