Apical asymmetric new-appearance opacity: a pancoast tumour

Clinical History

A 75-year-old male long-term smoker with one month history of several disorientation episodes underwent a brain CT, which was normal, and later a chest X-ray. No other relevant symptoms related to any other system were reported.

Imaging Findings

The abnormality on this chest radiograph may be easily missed as it is located in one of the areas known as “blind spots”: There is an opacity in the right lung apex, and also an absence of the second rib (Fig. 1).
Based on these findings, we sought for prior imaging studies in order to confirm that the lesion was new, as it happened to be in this case (Fig. 2). Subsequently, a thoracic and abdominal CT was performed, which revealed a right posterior apical mass measuring 5.6 x 5.4 x 4.8 (AP x T x CC) cm. The mass was accompanied by rib destruction and an adjacent soft-tissue mass invading the chest wall. (Figure 3)
There were also supraclavicular and paraoesophageal enlarged lymph nodes (Fig. 4).
Subsequently, a CT-guided lung biopsy was performed, which revealed squamous lung cancer.

Discussion

Pancoast tumour, also known as superior sulcus tumour, refers to a type of cancer that arises in the lung apex and invades the surrounding soft tissues [1]. Superior sulcus tumours are usually non-small cell lung cancers, and the most common histology encountered in the superior sulcus tumours are squamous cell bronchogenic carcinomas, as it resulted to be in this case [3].
Even though the tumour arises from the lung, symptoms are usually, if present, rarely pulmonary (such as cough, dyspnoea, or chest pain). Instead, they are a result of a growth and invasion of the local structures, which may cause the classical Pancoast syndrome, only seen in 25% patients, and which consists of shoulder-arm pain (if they grow and invade the bone), and Horner´s syndrome (ipsilateral miosis, ptosis and anhidrosis due to invasion of the cervical sympathetic plexus) [1].
Chest X-ray is usually the first imaging technique performed in patients with a pancoast tumour. Unfortunately, because of their location in the lung apices, this cancer is usually very difficult to detect, as the tumour may be seen as a subtle soft-tissue mass that may be confused with benign apical pleural thickening if it isn´t very big. The presence of associated bone destruction may be difficult to ascertain on the basis of radiographs, so in many patients, a thoracic CT is required to confirm the presence of a tumour [2].
The main objectives of CT in patients with a superior sulcus tumour are to confirm the presence of a pulmonary mass, to allow accurate staging of the disease, and to guide the biopsy. In the superior sulcus tumour, CT is the best modality for depicting bone abnormalities adjacent to the primary mass, such as rib and vertebral body erosion, information that may influence the surgical approach taken and the extent of the resection [2].
The presence of adenopathies is associated with poorer prognosis, and they may occur in up to 20%, as it happened in this case [2].
The key to be guided to the final diagnosis on this case was the detection of a new asymmetric apical opacity. The fact that the mass was accompanied by bone destruction led the differential diagnosis to neoplastic causes such as a bone tumour invading the lung or a lung cancer (pancoast tumour) causing bone destruction [4].

Differential Diagnosis List

Final Diagnosis

Pancoast tumour

URL:	https://eurorad.org/case/13495
DOI:	10.1594/EURORAD/CASE.13495
ISSN:	1563-4086