Case report. PET/CT appearance of desmoid tumour of the chest wall

Abstract

Desmoid tumours are rare, poorly circumscribed tumours that have a firm consistency and, although benign, have a remarkable tendency to infiltrate into surrounding structures. Extra-abdominal desmoid tumours involve mainly the extremities or the chest wall and are usually managed by wide radical resection. Moreover, desmoid tumours involving the chest wall are locally aggressive tumours with a high recurrence rate. We report a case of a pathologically proven desmoid tumour of the chest wall in a patient with a history of bilateral breast cancer and oesophageal cancer. We discuss the imaging appearances of this tumour on positron emission tomography combined with computed tomography (PET/CT) and magnetic resonance imaging.

Figure 1

A 72-year-old woman with a history of breast and oesophageal cancer underwent MRI of the chest wall. (a) Coronal T₁ and (b) axial T₁ fast spin echo (FSE) weighted sequences. (c) Axial T₂ single-shot fast spin echo (SSFSE) weighted sequences. (d) Heavily weighted T₂ SSFSE and (e) T₁ liver acquisition with volume acceleration (LAVA) with fat saturation post-contrast. On T₁-weighted MRI images, the tumour shows a signal intensity that is less than or equal to that of muscle, whereas T₂-weighted images have increased signal intensity with central areas of low signal that are thought to result from high collagen content. After contrast administration, the mass demonstrates intense and homogeneous enhancement.

Figure 2

A 72-year-old woman with a history of breast and oesophageal cancer underwent FDG-PET/CT for further evaluation of a right-sided posterior chest wall mass. (a) Coronal images: FDG-PET alone, CT alone and fused FDG-PET/CT (from left to right). (b) Axial images: FDG-PET alone, CT alone and fused FDG-PET/CT (from left to right). There is a large soft-tissue homogeneous mass within the right posterior chest wall that measures approximately 8×3.2 cm located between the chest wall and the latissimus dorsi muscle right beneath the inferior border of the scapula. This mass shows only mild FDG tracer uptake, with an SUV_max of 1.7.

Figure 3

“Right chest wall mass” consists of a soft-tissue resection specimen (11.5 × 9.5 × 4.5 cm).

Figure 4

Histological specimen with (a) haematoxylin and eosin and (b) β-catenin staining. The tumour is composed of collagen fibres and bland-looking spindle cells that stain positive for β-catenin, consistent with a desmoid fibrous tumour.