1

What is a chest wall tumour?

As the chest wall is composed of soft tissue (skin, adipose tissue, blood vessels, lymphatics, nerves, connective tissue and muscle), cartilage and bone, which interact to serve as a protective cage for the thoracic organs, any one of these components can be responsible for the development of a chest wall tumour.

Primary tumours are subclassified as benign or malignant and according to the tissue of origin (soft tissue, bone or cartilage).

Over 50% of chest wall masses are malignant, either from primary tumours or secondary lesions (via metastatic spread or direct invasion from nearby thoracic tumours).

2

Describe the classification of chest wall tumours

Primary tumours:

a)

benign soft tissue:

i)

cutaneous naevus (melanocytes);

ii)

lipoma (mature adipocytes);

iii)

haemangioma (non-encapsulated blood vessels);

iv)

lymphangioma (lymphatics);

v)

neurofibroma (peripheral nerve sheaths);

vi)

fibroma (fibroblasts) – including desmoid tumour;

vii)

rhabdomyoma (skeletal muscle);

b)

malignant soft tissue:

i)

malignant fibrous histiocytoma (no clear cell of origin) (Figure 1);

ii)

liposarcoma (mature adipocytes);

iii)

neurofibrosarcoma (peripheral nerve sheaths);

iv)

rhabdomyosarcoma (skeletal muscle);

v)

leiomyosarcoma (smooth muscle);

c)

benign bone or cartilage:

i)

fibrous dysplasia (medullary cavity of bone);

ii)

osteochondroma (metaphyseal cortex of bone);

iii)

chondroma (hyaline cartilage);

iv)

Langerhans cell histiocytosis;

d)

malignant bone or cartilage:

i)

chondrosarcoma (hyaline cartilage);

ii)

osteosarcoma (metaphyseal cortex of bone) (Figure 2);

iii)

Ewing’s sarcoma family of tumours – including Askin tumour, primitive neuroectodermal tumours (PNET) and Ewing’s sarcoma;

iv)

plasmacytoma.

Secondary tumours – which represent metastatic disease from other primary tumours or invasion of local tumours, including:

a)

breast carcinoma (Figure 3);

b)

lung carcinoma;

c)

mesothelioma.

3

What are the clinical features of a chest wall tumour?

The clinical presentation and symptoms vary according to the tumour:

a)

size;

b)

rate of growth;

c)

underlying diagnosis.

Although the majority of chest wall tumours present with pain or swelling, slow-growing tumours may be painless.

Systemic features of malaise, fatigue, weight loss and night sweats may also be present.

A significant proportion are discovered incidentally on thoracic radiological imaging.

4

What are the principles of investigation in a patient with a chest wall tumour?

Chest radiograph (CXR) may demonstrate:

a)

chest wall tumour (Figure 4);

b)

associated bony erosion or lytic lesions;

c)

mediastinal lymphadenopathy or invasion;

d)

pulmonary metastases.

Computed tomography (CT) scanning can provide more detailed information regarding the chest wall tumour and the relationship of the tumour to neighbouring structures, as well as the features identifiable on the chest radiograph (Figure 5).

Magnetic resonance imaging (MRI) can be used to assess the relationship of the tumour to adjacent neurovascular structures, the vertebral column and apex of the chest (Figure 6).

Radionucleotide bone scanning may be used to look for bone metastases (Figure 7).

Positron emission tomography (PET) scanning can also be used to identify metastatic disease.

5

What are the principles of management in a patient with a chest wall tumour?

Complete radiological investigation to determine the origin of the tumour, extent of the disease process and presence of any extrathoracic spread.

Histological diagnosis obtained by fine needle aspiration (FNA), incision biopsy or excision biopsy, depending on the size and location of the lesion.

Discussion at a multidisciplinary team meeting, (including surgeons, oncologists, radiologists and histopathologists) to discuss the optimal treatment regime (including surgery, chemotherapy, radiotherapy or palliation), depending on the tumour histology, extent of spread and fitness of the patient.

6

What are the characteristic features of a cutaneous naevus?

Cutaneous naevi represent aggregates of melanocytes.

They need to be differentiated from a melanoma.

Treatment is by wide local excision.

7

What are the characteristic features of a lipoma?

Lipomas are composed of mature adipocytes.

They are excised for cosmetic or diagnostic reasons.

If the lesion invades the underlying muscle, more extensive surgery may be required.

8

What are the characteristic features of a haemangioma?

Haemangiomas represent groups of non-encapsulated blood vessels.

They may originate within the chest wall itself or protrude from the thoracic cavity or mediastinum into the chest wall.

Haemangiomas may be superficial or deep and simple or cavernous.

They are common at birth and in young children and usually present as painful masses.

Haemangiomas are treated by wide local excision, ensuring negative resection margins to reduce the incidence of local recurrence.

9

What are the characteristic features of a lymphangioma?

Lymphangiomas are derived from lymphatic vessels and may be simple or cavernous in nature.

They are commonly located in the head, neck and axillary regions, with an increased incidence in children.

Lymphangiomas are treated by complete surgical excision.

10

What are the characteristic features of a neurofibroma?

Neurofibromas arise from peripheral nerve sheaths and are often associated with neurofibromatosis (von Recklinghausen’s disease).

Cutaneous neurofibromas arise from the dermis, and are often pigmented and pedunculated. They have a low potential for malignant transformation and, hence, are excised for only cosmetic reasons.

Plexiform lesions, which arise from a host nerve, often have a dumbbell shape on CT or MRI. In contrast to cutaneous lesions, they have a high potential for malignant transformation and, hence, should be treated by surgical excision.

11

What are the characteristic features of a fibroma?

Fibromas are rare soft-tissue tumours that arise from fibroblasts.

They are slow growing and present near joints or on pleural surfaces.

Fibromas are excised for symptomatic or cosmetic reasons.

12

What are the characteristic features of a desmoid tumour?

Desmoid tumours are a variety of fibromas, which arise from fibroblasts in connective tissue located in deep fascia and muscle.

They are associated with Gardner’s syndrome, which is an autosomal dominant mutation of the adenomatous polyposis gene.

Desmoid tumours usually occur in younger patients (15-30 years of age), with an equal male and female distribution.

Patients usually present with pain in the shoulder and anterolateral aspect of the chest wall but may also develop symptoms of paraesthesia or muscle weakness.

Although desmoid tumours have not been reported to have malignant potential, they can invade locally.

Treatment is by surgical excision with wide resection margins, as local recurrence rates are high.

Chemotherapy and radiotherapy have been used to reduce the incidence of local recurrence.

13

What are the characteristic features of a rhabdomyoma?

Rhabdomyomas arise from skeletal muscle.

They occur more commonly in adults.

Rhabdomyomas are excised for symptomatic or cosmetic reasons.

14

What are the characteristic features of a malignant fibrous histiocytoma?

Malignant fibrous histiocytomas are characterised by cytologic pleomorphisms, multi-nucleated cells with storiform architecture, inflamed collagen and foamy macrophages.