Pancoast tumour

Clinical History

A 58-year-old woman presented with history of weight loss.

Imaging Findings

A 58-year-old woman presented with weight loss, upper back and right arm pain. Past medical history was unremarkable. She was an ex-smoker. There was no neurologic deficit and no Horner’s syndrome was present. Chest radiograph showed a subtle opacity in the right apex (Fig. 1). Apical view was requested for further evaluation (Fig. 2). It showed slightly more obvious right apical opacity. Following this, urgent CT staging (Fig. 3) showed a right lung apical mass, pleural thickening and osteolysis of the medial end of 2nd rib and adjacent 2nd thoracic vertebral lamina. There were no other lung lesions, no mediastinal lymphadenopathy and no disease below the diaphragm. Primary diagnosis made on the basis of CT findings was a pancoast tumour. Discussion at the clinicoradiologic meeting recommended biopsy of the lesion and further imaging with MRI and PET. Ultrasound (Fig. 4) guided biopsy was performed.
MRI (Fig. 5) of the spine was performed to further assess the spinal involvement. This showed a neoplastic mass arising from the apex of the right lung involving the neural exit foramina of the T1 and T2 nerve roots.
PET (Fig. 6) showed FDG avid right apical tumour with right supraclavicular extension and involvement of adjacent ribs and vertebral bodies. No discrete metabolically active nodes in the chest or supraclavicular fossa (separate from the tumour) or distant metastasis.
The histology of the biopsy specimen was consistent with keratinising squamous cell carcinoma.

Discussion

Pancoast tumours are neoplasms of pulmonary origin located at the apical pleuropulmonary groove (superior sulcus). Initially, patient may present with arm, shoulder or scapular pain. By direct extension, Pancoast tumours typically involve the lower trunks of the brachial plexus, intercostal nerves, stellate ganglion, adjacent ribs, and vertebrae. If the tumour extends to the sympathetic chain and stellate ganglion, Horner syndrome and anhidrosis develop on the ipsilateral side of the face and upper extremity.

More than 95% of Pancoast tumours are non–small cell carcinomas, most commonly squamous cell carcinomas (52%) or adenocarcinomas and large cell carcinomas (approximately 23% for each subtype). Small cell carcinomas are seen in fewer than 5% of cases [1].

Errors in radiological interpretation can significantly delay the treatment of pancoast tumours. In a study carried out on patients with pancoast tumours at Fukuroi Municipal Hospital, Japan (1999 to 2004), several radiological errors were identified leading to significant delay in treatment [2].

Differential diagnoses of masses in the apical chest include primary tumours of the thyroid, larynx and pleura. Other causes may include infectious disorders of the lung, aneurysms of the subclavian vessels, amyloid of pleura and multiple myeloma. The differential diagnoses of arm and shoulder pain are extensive; however, primarily, thoracic outlet syndrome and cervical disc disease must be excluded. Staging is determined by the location of the lesion and its metastases. The true Pancoast tumour is usually T3, which describes the extension of the tumour through the visceral pleura into the parietal pleura and the chest wall. Pancoast tumours are classified as T4 when mediastinal invasion, cervical invasion, or both have occurred. Pancoast tumours were once considered universally fatal. However, improvements in combined modality therapy and the development of new techniques for resection have made curative treatment possible for these tumours. The perfect candidate for resection has a carcinoma restricted to the chest with T3N0M0 staging. Contraindications to surgery include: extensive invasion of the neck, brachial plexus or vertebrae; perinodal mediastinal extension; and peripheral metastases [3]. The bimodality approach of induction radiotherapy followed by surgical resection has been the accepted standard of care for the last 50 years, with reported 5-year survival rates of 30% in selected patients. However, two recent prospective multicentre phase II studies using a trimodality approach of induction concurrent chemoradiotherapy followed by surgical resection (followed by two further cycles of adjuvant chemotherapy in one of the studies), have reported 5-year survival rates of 44-56%. This has led to some authorities advocating the trimodality approach as the new standard of care for the management of Pancoast tumours [4].

Differential Diagnosis List

Final Diagnosis

Pancoast tumour - keratinising squamous cell carcinoma.

URL:	https://www.eurorad.org/case/8577
DOI:	10.1594/EURORAD/CASE.8577
ISSN:	1563-4086