Pleural tumor

Cancer of the pleura

Pleural cancer is a serious and potentially fatal form of cancer that affects the pleura, the double serous membrane that lines and supports the lungs in the chest cavity. More precisely, we speak of pleural mesothelioma when the tumor affects exclusively the mesothelium (epithelium that surrounds all the large serous cavities such as the pleural cavity).

In common parlance the terms "mesothelioma" and "pleural tumor" are used interchangeably. In fact, it would be more correct to speak of "pleural mesothelioma" (and not simply "mesothelioma") since two other large anatomical cavities - peritoneal cavity and pericardial cavity - are lined by the mesothelium, therefore they are possible targets of mesothelioma.
Let us briefly recall that the pleural variant is the most common tumor form among the three types of mesothelioma: over 75% of mesotheliomas are diagnosed at the level of the pleura.
Let's see in more detail which are the most common tumors affecting the pleura.

Pleural tumors can be divided into 4 sub-categories:

1. Malignant pleural mesothelioma
2. Solitary fibrous tumor of the pleura
3. Secondary malignancies (to other cancers)
4. Lymphomas

In this article the focus will be on the study of malignant pleural mesothelioma - the most frequent malignant tumor originating from the pleura - and of the fibrous solitary tumor of the pleura.

Pleural mesothelioma

As analyzed, pleural mesothelioma is a widespread form of cancer that affects the mesothelium of the pleura. Primary tumors of the pleura seem to arise following repeated exposure to a very limited number of exogenous agents: asbestos (or asbestos) and its derivatives. In any case, what has been said does not exempt from the possibility that other factors may intervene in the etiopathogenesis of this neoplasm. In fact, other predisposing elements are also called into question, such as genetic alterations and previous infections sustained by the SV40 virus (Simian vacuolating virus 40 or Simian virus 40).

CAUSES

Exposure to asbestos fibers appears to increase the risk of lung cancer by 5 times. The asbestos fibers, which have reached the lungs, are literally incorporated by the pleura; subsequently, the material travels in extrapulmonary sites up to the ribs. Already in the initial stage, the tumor masses can involve both serous sheets that make up the pleura, even if the parietal membrane seems to be more affected than the visceral one.

SYMPTOMS

For further information: Pleural Mesothelioma Symptoms

The asbestos fibers, reaching the lung level, can cause an "immediate inflammation of the pleura (pleurisy), thus causing stabbing chest pain and dyspnea. In other cases, the asbestos fibers create tumor in the pleura after a rather long time, triggering the first symptoms after a few years (usually after 3 years).

A lit indicator of pleural mesothelioma is the neoplastic pleural effusion, perceived by the patient as an abnormal pain in the chest, which is accentuated with coughing and deep breaths.
Note the particular speed with which a pleural tumor of this type advances: the growth of diseased cells is in fact surprisingly rapid. In a short time, the tumor can cover the entire lung cavity, making breathing very painful. In the advanced stages, the tumor also spreads to nearby organs, such as the heart, lymph nodes and abdomen.
In addition to the stabbing pain when breathing, other symptoms can signal to the patient that something in the body is not working properly:

• Blood clots
• Difficulty with speech
• Respiratory difficulties
• Shortness of breath
• Lack of appetite
• Unwanted weight loss
• Hoarseness
• Possibly bloody pleural effusion (hemothorax)

DIAGNOSIS

From the analysis of a sample of pleural fluid obtained by thoracentesis it is possible to diagnose the pleural tumor: the anomalous cellular composition, in fact, can ascertain the diagnosis. The liquid taken is also dense and stringy due to the abnormal quantity of hyaluronic acid developed.
The thoracentesis must be preceded by a screening test (X-ray or CT). Also the pleural needle biopsy in VATS (Video Assisted Thoracic Surgery) and thoracotomy may be other indicated diagnostic options.

THERAPY

Unfortunately, pleural mesothelioma is a particularly aggressive malignant form of cancer. The therapy is almost ineffective in the vast majority of affected patients. However, the cancer patient is almost always treated with radiotherapy combined with chemotherapy. Whenever possible, surgical therapy is also used, which consists in the removal of the tumor mass.
Many patients die 6-7 months after the onset of this form of pleural cancer.

Solitary fibrous tumor of the pleura

Rare normally benign neoplasm, fibrous solitary tumor of the pleura arises from the mesenchymal cells of the subpleural connective tissue. This neoplastic form affects both the serous sheets constituting the pleura (visceral and parietal); only rarely does cancer also involve the mediastinum, pancreas, neck, sinuses and lung.
Solitary fibrous tumor of the pleura can ideally affect men and women of all ages. However, most of these cancers have been observed to affect the over 60s.
Solitary fibrous tumor of the pleura has a much lower incidence than pleural mesothelioma.

SYMPTOMS

This pleural tumor variant has a mostly silent course. Not surprisingly, cancer is often diagnosed randomly, via a simple test imaging.
When symptomatic, prodrome related mostly to the structural extension of the neoplastic mass to the nearby anatomical structures are documented in the patient. In this case, the larger the mass is, the more pronounced the symptomatology: dyspnoea, chest pain and cough are three very recurrent symptoms in cancer patients with pleural fibrous tumor. Less frequently, however, the patient with this form of pleural cancer complains of anorexia, chills, fever, hemoptysis, swelling of the lower limbs, paraneoplastic manifestations (osteoarthropathy and hypoglycemia due to hyperproduction of the "insulin-like growth factor II), syncope and pleural effusion. In the giant forms, it is possible to find hypomobility of the hemithorax involved in the neoplasm.

DIAGNOSIS

As mentioned, fibrous tumor of the pleura is often diagnosed accidentally, by means of a simple radiological investigation performed for other reasons. Other diagnostic strategies aimed at ascertaining pleural cancer include: routine haematological examinations, upper abdomen ultrasound, CT, chest CT and MRI. Some patients undergo an additional diagnostic test, known as PET or Positron Emission Tomography, useful in some selected subjects in which a probable malignant tumor degeneration is suspected.

THERAPY

The treatment to remove this pleural tumor is surgical: all the tumor mass must be removed, with possible excision of one or more portions of the parietal / diaphragmatic / mediastinal pleura. Neither radiotherapy nor chemotherapy are first choice therapeutic treatments (clearly in the absence of malignant tumor cells).

What to know

The table shows the key concepts of fibrous solitary tumor of the pleura.

Etiology

Unknown. There is no demonstrated correlation with smoke or asbestos dust

Structure of the tumor

Fibrous solid mass ranging in size from 5 to 20 cm

Target of the tumor

Visceral and parietal pleura (most frequently)

Prognosis

Favorable in most cases (following surgical excision). Bad prognosis in 12-33% of patients

Histological analysis

Sparse spindle cells
Round-oval cell nucleus
Distribution of chromatin: regular
Cytoplasm: eosinophilic
Presence of collagen mixed with cancer cells

Symptoms

Solitary fibrous tumor of the pleura almost always proceeds asymptomatically. In the advanced stage there is a particular compression symptomatology, accompanied by dyspnea, pain and cough. Possible anorexia, night sweats, swelling of the lower limbs, hypoglycemia, osteoarthropathy and fever

In most cases, fibrous solitary tumor of the pleura is benign, although it sometimes presents signs of histological malignancy. After surgery, the prognosis is generally excellent.