A Lung Tumor With Popcorn-Like Calcifications

Session 31

A 55-y/o heavy smoker is shown to have a peripheral, well-circumscribed mass with popcorn-like calcifications in the RUL. What is the lesion likely composed of?

Dr. Karen Shackelford from BoardVitals joins us once again as we delve into another case to prepare you for your Step 1 or Level 1 exam. Save 15% off their QBank by using the coupon code BOARDROUNDS.

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[01:48] Question of the Week:

A 55-year-old male with a 40-year history of smoking who undergoes a low-dose chest CT for lung cancer screening. Imaging results show a peripherally located, well-circumscribed 2-cm mass in his right upper lobe. It has a popcorn-like calcification. Which of the following describes the characteristics of this mass?

(A) is composed predominantly of fattened cartilage

(B) is composed of poorly differentiated neuroendocrine cells

(D) is caused by keratin production and intracellular desmosomes

(E) is formed by caseating granuloma around the causative organism

[03:00] Thought Process Behind the Correct Answer

The correct answer here is

Answer choice E refers to TB and this doesn’t sound like TB as there are popcorn lesions with TB.

Answer choice A would sound more or less of a benign tumor. B sounds like a malignant small cell lung cancer. C would make you think of adenocarcinoma.

[03:00] Thought Process

Answer choice A would sound more or less of a benign tumor. B sounds like a malignant small cell lung cancer. C would make you think of adenocarcinoma. Answer choice E refers to TB and this doesn’t sound like TB as there are popcorn lesions with TB.

The correct answer here is A. A well-circumscribed lung tumor with predominantly fattened cartilage is a hamartoma. A trick that helped me remember this back in medical school is that “popcorn isn’t bad.” It’s the most common benign tumor of the lung. It usually contains connective tissue, fat, and cartilage. It’s classically associated with popcorn-like calcifications on imaging. They are relatively large, well-demarcated and they rarely impinge on surrounding structures.

For the management of pulmonary hamartoma, it would be more beneficial not to undergo surgery. The approach to those tumors is individualized unless it’s diagnosed as a stable nodule. Karen stresses the importance of not overdiagnosing people. Once you figure out it’s not causing any problems, you just leave it there.

[06:08] Understanding the Other Answer Choices

The poorly differentiated neuroendocrine cells is a small cell lung cancer. It’s a really aggressive malignancy that is most common in smokers. They usually have irregular margins and has a really poor prognosis largely because it tends to metastasize.

Significant glandular components are characteristic of adenocarcinoma. It’s the most subtype of lung cancer. It has both solid and ground blast components on imaging. It’s a pretty heterogenous-looking tumor. It’s usually peripherally located.

Keratin production and intracellular desmosomes are characteristic of squamous cell carcinoma. It’s a common form of non-small cell lung cancer. It originates from epithelial cells along the airways. They’re usually centrally located, often associated with the larger bronchi.

Caseating granuloma is characteristic of pulmonary tuberculosis around the causative organism. It usually looks like a focal cavitary lesion often in upper lobes. The patients usually have a risk factor like travel to an area where TB is endemic. Or there’s exposure to infected individuals or incarceration.