Case 7


Section 1

Look at images 1 and 2. This case shows multiple nodules. Asymmetry of the lungs is due to collapse of the left upper lobe.

1. Are the nodules focal or diffuse?

2. What is the anatomic location of the nodules?

a) Primarily bronchovascular
b) Primarily centrilobular
c) Primarily pleural
d) Random

Answers

Image 1

 

Find the left upper lobe bronchus leading into the left upper lobe.

Outline the collapsed left upper lobe.

In the right lung, find 3 pleural nodules.

Find 3 nodules at the end of vessels in the right lung.

Find 4 or 5 nodules along the fissure (F) in the right lung.

 

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Image 2

 

Find 2 centrilobular nodules in the right lung.

Find a nodule at the end of a vessel in the posterior right lung.

Compare the random nodules in this case with the diffuse centrilobular nodules in Case 2. (Use the "back" button on the menu bar to return.)

vascnod1cvnod1cvnod2


Section 2

Histology of a Nodule

This rounded, subpleural structure, about 0.5 cm in diameter, corresponds to the subpleural lesions in the images above. In this case, no cellular structures are present except at the edge.

1. What are possible causes of this nodule?

2. What does the homogeneous pink material in the nodule represent?

Answers

 

Differential diagnosis of random nodules on HRCT: Diagnoses include hematogenous metastasis (particularly from thyroid, kidney, and breast) and miliary infections. Langerhans' cell histiocytosis, sarcoidosis, and silicosis are common causes of nodules, but such nodules are rarely diffuse and haphazard.

HRCT diagnosis: Metastatic breast cancer with hematogenous spread throughout the lungs and endobronchial metastasis to the left upper lobe, resulting in collapse.

Histologic differential diagnosis: Metastatic tumor. Infection should be considered. See Case 3 for another example of hematogenous metastatic tumor. (Use the "back" button in the menu bar to return.)

Summary of diagnostic features of numerous hematogenous metastatic nodules on HRCT

Comment: HRCT can both diagnose hematogenous metastases and determine whether the tumor is viable by observing enlargement of nodules over time.

See Case Study 24 for an example of metastatic tumor with an unusual appearance.

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1. Diffuse

2. Random

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Left upper lobe bronchus

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Collapsed left upper lobe

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Pleural nodule(s)

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Nodule at end of vessel

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Four or 5 nodules along the fissural pleura

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Nodule at the end of a vessel

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Centrilobular nodule(s)

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1. Possible causes include infection and tumor. This particular patient had known metastatic testicular carcinoma. The necrosis of the tumor may have resulted from therapy or ischemia or both.

2. The homogeneous pink material represents necrosis.

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