Dr. Pepe’s Diploma Casebook: CASE 129 – SOLVED!

Dear Friends,

Today’s radiographs belong to a 54-year-old man with vague chest complaints.

What do you see?

Check the images below, leave your thoughts in the comments section, and come back on Friday for the answer.

Click here for the answer

Findings: PA radiograph shows a poorly defined paramediastinal opacity (A, arrow) that is projected over the trachea in the lateral view (B, arrow).

Coronal and sagittal enhanced CT demonstrate a spiculated lung nodule (C and D, arrows), highly suspicious of malignant disease.

Final diagnosis: carcinoma of the lung

In Diploma cases 123126, I reviewed the various presentation forms of lung carcinoma as an aid to identify them. In the next two Diplomas, I intend to discuss how to avoid missing them and incurring a potentially harmful delay in the diagnosis.

Overlooking lung cancer has two main causes:

Faulty visualization, in which the lesion is hidden by chest structures
Failure of recognition: the neoplasm is seen, but is confused with benign disease

In this presentation I will review the causes of faulty visualization, which may be due to the lesion being hidden by chest organs or obscured by overlying lung disease.

Overlooking a lesion is our most common mistake, accounting for around 50% of errors. A carcinoma in any part of the lung can be missed (Fig. 1), but it occurs more commonly in what is called the blind areas of the chest. In the PA radiograph these include the apical region, the hila and mediastinal shadows, and the areas behind both hemidiaphragms (Fig. 2).

Fig. 1. Preoperative radiograph for knee surgery, read as normal. A faint opacity in the LUL was not noticed (A, arrow). Nine months later, a small cavitated nodule is seen in the same location (B, arrow). Axial CT confirms the presence of a thick-walled cavitated nodule. Surgical diagnosis: adenocarcinoma

Fig. 2. The blind areas on the PA radiograph are depicted in A (shaded area). A lung nodule is visible behind the left heart (A, arrow), confirmed with coronal CT (B, arrow). Diagnosis: adenocarcinoma.

The lung apices are difficult to evaluate because of the superimposed first ribs and clavicles (Fig. 3). Radiologists miss 25% to 50% of nodules in the apical regions. The missed nodules have a mean size of 1.6 cm (Fig. 4).

Fig. 3. 76-year-old man with vague chest symptoms. Initial film shows a faint right infraclavicular nodule that was overlooked (A, arrow). One year later, the nodule has grown markedly (B, arrow). Diagnosis: melanoma.

Fig. 4. 49-year-old man with asthenia. There is a nodule in the left apex (A, arrow), that was not recognized. Enhanced CT study, ordered to rule out a thymoma, discovered the apical lung nodule (B, arrow). Diagnosis: lung carcinoma.

The hilar regions are imprecise areas where small tumors in the vicinity may go unrecognized if the hila are not examined carefully (Fig. 5). Any increased opacity of the hilum should always be investigated to exclude malignancy (Fig. 6).

Fig. 5. 68-year-old man with cough and weight loss. Initial film showed a perihilar lung nodule that was not reported (A, arrow). Ten months later the nodule has increased in size. Biopsy confirmed the diagnosis of carcinoma.

Fig. 6. 72-year-old man, smoker, with cough and hemoptysis. PA radiograph shows increased opacity of the right hilum compared to the left (A, arrow). Enhanced axial CT depicts a large mass behind the right hilum, invading the mediastinum. Large cell carcinoma.

The mediastinal shadow can hide large-size tumors in the PA view (Fig. 7). That is why a lateral view should always be taken when studying the chest.

Fig. 7. Large lung tumor in the RUL, hidden by the mediastinal shadow in the PA view (A, arrow). The tumor is clearly visible in the lateral view (B, arrow) and confirmed with axial CT (insert, arrow).

The hemidiaphragms hide a significant portion of the lower lobes. A carcinoma in this location may be barely visible in the PA view and better seen in the lateral projection (Figs. 8 and 9).

Fig. 8. RLL carcinoma, barely visible behind the hemidiaphragm in the PA view (A, arrow). It is better seen in the lateral projection, located in the posterior costophrenic angle (B, arrow). Coronal CT confirms a necrotic tumor at the base of the right lung (arrow, insert).

Fig. 9. 82-year-old man with chest trauma and fractured ribs. There is a large mass in the RLL that could be interpreted as a Bochdalek hernia (A and B, arrows).

Coronal and sagittal enhanced CT demonstrate a large necrotic mass in the RLL (C and D, arrows). Needle biopsy confirmed the diagnosis of carcinoma.

Faulty visualization can also be due to the tumor being obscured by overlying lung disease, either acute (Fig. 10) or chronic.

Fig. 10. 68-year-old man with acute pneumonia that obscures a carcinoma in the RUL (A, arrow). The tumor becomes evident when the acute infiltrate has regressed (B, arrow).

Chronic diffuse lung disease can also hide a malignancy. This is important to consider because patients with interstitial lung disease are known to have a higher incidence of tumors (Figs. 11 and 12).

Fig. 11. 78-year-old man with severe emphysema and chronic left lung changes. A RLL carcinoma is barely visible in the PA radiograph (A, arrow). Coronal CT clearly demonstrates the RLL neoplasm (B, arrow)

Fig. 12. Middle-aged man with pulmonary fibrosis awaiting lung transplantation. The initial radiograph shows diffuse lung disease. Ten months later there is an increased opacity in the outer right lung (B, circle), which becomes mass-like 2 months later (C, arrows). Axial CT confirms the mass (insert, arrow), proven to be a carcinoma on needle biopsy.

Follow Dr. Pepe’s advice:

1. Lung tumors may be hidden in the “blind” areas of the PA view.

2. These include the apices, hilar and mediastinal shadows, and both hemidiaphragms.

3. Lung disease, either acute or chronic, can also hide lung tumors.

5 thoughts on “Dr. Pepe’s Diploma Casebook: CASE 129 – SOLVED!

  1. Hello professor,
    There is right irregular paratracheal opacity on pa view, projecting behind trachea on lateral view – pulmonary, vascular or esophageal lesion suspected.


  2. Good morning! Difficult case!!

    He is a man but he has breast.
    Tonniform thorax, probable because of enphysema.
    I see a slightly opacity in the right cardiophrenic sinus (maybe it is fat – not relevant in the lateral view).
    In the lateral view there is an increased density proyected over the aortic arc.
    Degenerative changes in the first right costo-esternal join.

    Right paratracheal widening and nodular hilios…(adenopahty? – 1,2,3 sign)


  3. As you can see, the case was not difficult. Hope it increases your awareness about hidden carcinomas.
    Congratulations to Borsuk, who was the first to detect the abnormality.


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