Progressive dyspnea with a classic radiological sign.

A 76-year-old gentleman presented to the outpatient department with chief complaints of dyspnea on exertion and chronic cough since the past few months. On examination, there was shift of the trachea to the right and percussion yielded dull notes over the right supraclavicular area, upper two intercostal spaces anteriorly and the superior aspect of the interscapular region on the right side. The left-sided percussion was unremarkable. On auscultation, breath sounds were decreased in the region of the right upper lobe. A chest radiograph was ordered [Figure 1a].

Figure 1a

Can you identify the radiological sign depicted in this plain radiograph?

QUESTIONS

Q1: What is the classic radiological sign seen in the plain radiograph?

Q2: What is the cause of this typical radiological appearance?

Q3: What is the most common cause of this sign?

ANSWERS

Answer 1: The Golden S sign or the “reverse S sign.”

Answer 2: The Golden S sign is seen when there is right upper lobe atelectasis due to a centrally located mass. The collapse appears as a wedge-shaped homogeneous opacity in the upper zone. The central mass produces downward convexity of the medial portion of the minor fissure, which, with the lateral concave part, gives rise to the characteristic reverse S appearance [Figure 1b]. A computed tomography (CT) scan of the thorax was performed, which showed a central mass obstructing the right upper bronchus and few well-defined nodular opacities in the basal segments of the right lung [Figures 2–4].

Figure 1b

Plain radiograph of the chest (PA view) showing a well defined homogeneous opacity in the right upper zone. The lower border of the opacity forms the characteristic “reverse S” or the “Golden S” configuration. There is associated ipsilateral shift of the trachea. Fewill-defined opacities are also noted in the right lower zone

Figure 2

Post contrast axial CT scan at the level of the tracheal bifurcation shows a mass obliterating the right upper lobe bronchus

Figure 4

Post-contrast sagittal reformat images in lung window settings show collapse of the right upper lobe with pulling up of the otherwise horizontal minor fissure which now appears concave superiorly. Few nodular soft tissue opacities are also seen in the middle lobe

Post contrast CT coronal reformats show right upper lobe collapse secondary to a mass in the right upper lobar bronchus

Answer 3: The most common cause for the Golden S sign is a primary bronchial carcinoma. In our case, when we investigated further, the patient gave a history of having renal cell carcinoma for which the patient was operated nearly 3 years ago. A CT-guided biopsy was performed, which confirmed the central hilar mass to be metastases from a clear cell type renal carcinoma.

DISCUSSION

The features suggestive of a lobar collapse on a plain radiograph are broadly divided into direct signs such as homogenous opacity, displacement of the fissure and crowding of bronchovacular markings and indirect signs including shift of trachea towards opacification, elevation of the hemidiaphragm, mediastinal displacement, hilar displacement and compensatory hyperinflation of the rest of the lobes.[1] The right upper lobe is bounded inferiorly by the minor fissure and posteriorly by the major fissure. A right upper lobe collapse can cause displacement of the minor and the major fissures superiorly and medially with compensatory hyperinflation of the rest of the lobes. On a frontal chest radiograph, the fissures appear concave superiorly. The collapsed lung is seen as a wedge-shaped opacity with its broad base toward the chest wall and apex at the hilum. The Golden S sign is seen when there is right upper lobe atelectasis due to a centrally located mass.[2] The central mass produces downward convexity of the medial portion of the minor fissure, which, along with the lateral concave part, gives rise to the characteristic reverse S appearance. The sign was first described by Golden in cases of bronchial carcinoma, which still remains the most common cause of the appearance.[34] It can also be seen in metastasis, primary mediastinal tumor or enlarged lymph nodes.[5] It is not a specific sign, but alerts the clinician and the radiologist regarding the possibility of a central obstructing mass as a cause of atelectasis, as it did in our case. Renal cell carcinoma frequently metastasizes to the lungs. Pulmonary metastatectomy surgery is safe, and has proven to be curative in more than one-third of the patients with a low rate of postoperative morbidity and mortality and a 5-year survival rate of 30–40%.[6] Hence, picking up pulmonary lesions early in such patients can help ensure better survival.

The purpose of this quiz is to highlight that a simple plain radiograph can serve as an efficient and cost-effective screening tool. In spite of the advent of newer modalities, the plain radiograph still continues to provide vital information to radiologists and clinicians worldwide.