Pleural tumors

Joseph Lieutaud was the first to describe a primary pleural tumor in 1767. However, the scientific discussion of pleural tumours only took place much later. For this reason, Wagner's work of 1870 is considered the first treatise on the pleural mesothelioma (Drings 1998).

Lebert was the first to describe the benign chondrome of the pleura in 1845 (Edling 1938).

In the case of pleural tumours, a distinction is made between primary and secondary tumours.

Primary tumours

Primary tumours make up only about 3% of all pleural tumours. They originate in 80 % from the visceral pleura and in about 20 % from the parietal pleura [Drings 1998]).

The primary tumours are divided into benign and malignant tumours.

Benign tumours include:

• lipomas (the most frequent benign tumors [Fisseler-Eckhoff 2015])
• benign fibrous pleural mesothelioma (usually originating from the visceral pleura, often stalked [Matthys 2008])
• Fibromas (70% from the visceral pleura and 30% from the parietal pleura [Fisseler-Eckhoff 2015])
• Angiomas
• Neurinomas
• Chondromes

The transitions from benign to malignant tumours are not rare. For example, every 4th fibrous pleural tumor is malignant (Köhler 2010).

Primary malignant tumors include:

• Mesothelioma (primarily originating from the parietal pleura)
• epithelioid mesothelioma

and the much rarer:

• lymphomas
• Fibrosarcoma
• Angiosarcomas
• Liposarcomas

Sarcomas are rarities in general (Matthys 2008)

Secondary tumours:

Secondary tumors account for about 97%.

They include:

• Pleural carcinomatosis
• Lymphangiosis carcinomatosa of the pleura

Pleural tumours are rare compared to tumours of the lung.

The proportion of primarily malignant tumours of the pleura is only 5% (Ferlinz 1992) or 2 per 1 million inhabitants (Steinbeck 2005). The disease occurs 4 times more frequently in men. The average age is 63 years.

However, the incidence in asbestos-exposed persons is 300 times higher than in the normal population (Fisseler-Eckhoff 2015). Up to 90 % of mesothelioma diseases are due to asbestos exposure (Craighead 2011).

Primary benign pleural tumours are very rare overall. The most frequent are lipomas (Fisseler-Eckhoff 2015) . The benign pleural mesothelioma on the other hand is extremely rare. Schumacher wrote in 1998 that so far only about 500 cases have become known worldwide. This tumor usually occurs around the 5th or 6th decade of life. Men and women are equally affected.

Primary diffuse malignant pleural mesothelioma results from exposure to asbestos. The association is now recognized by the employers' liability insurance association and is compensated accordingly. The latency period between exposure and disease is approximately 20-40 years (Steinbeck 2005).

Currently, the SV 40 virus is also controversially discussed as the causative agent (Fisseler-Eckhoff 2015).

The secondary tumors are metastases from the following primary tumors such as:

• Lung carcinoma (most common)
• Breast carcinoma
• Carcinoma of the gastrointestinal tract
• Sarcomas
• Ovarian carcinoma
• Pancreatic carcinoma
• Melanoma

Most patients with a benign tumor of the pleura are asymptomatic. The diagnosis of the tumour is therefore often a chance finding.

The following symptoms may occur in the rest of the clientele:

• Hypoglycaemia (some tumors of the pleura - including the benign ones - are endocrine active, especially in compression [Köhler 2010])
• Pleural bleeding (especially with fibrous tumours)
• Chest pain
• hypertrophic osteoarthropathy
• Chesty cough
• Dyspnea
• Unclear pleural effusion (in over 90 % of malignant pleural tumors [Matthys 2008])
• in advanced stages, general tumour signs such as reduced performance, weight loss, inappetence

The primary benign mesotheliomas of the pleura usually originate from the visceral pleura. They grow slowly and solitary. Pleural effusion is found in only about 10 % of cases (Steinbeck 2005).

Primary malignant mesotheliomas mostly start in the parietal pleura and are also found in the visceral pleura leaf in the later stage (approx. 80 %). However, they can also occur in the area of the peritoneum, the pericardium and the testicular sheaths (Fisseler-Eckhoff 2015). Primary malignant mesotheliomas are a so-called "asbestos-related signal tumour" for an inhalative (mostly occupational) exposure to asbestos fibres. The term asbestos-related signal tumour was coined by Selikoff in 1965.

However, mesotheliomas are often only discovered in an advanced tumour stage.

Sonography

Malignant processes often involve a pleural effusion. Fluid-filled cavities in the tumour can also simulate an encapsulated effusion of the thoracic wall.

X-ray image

In malignant mesothelioma the thoracic view mostly shows a unilateral effusion with a pleural callosity (Siewert 2006).

Computer tomography

In malignant mesothelioma there is a nodular thickening of the parietal pleura which shows an increase in size from cranial to caudal (Siewert 2006). Computed tomography is the gold standard for mesothelioma, as it allows both the extension of the tumor and a possible lymph node involvement to be diagnosed.

Based on the density measurement, a suspected lipoma can be determined under certain circumstances (Köhler 2010).

Biopsies

A biopsy is performed under sonographic or CT control or with the help of a thoracoscopy.

With regard to biopsies, it should be noted that the malignant mesothelioma often shows an initially flat, invasive growth in its early phase and the biopsies should therefore be sufficiently deep and of sufficient size (Fisseler-Eckhoff 2015).

Cytology

The cytology only leads to the detection of a mesothelioma in 35 % - 50 %. In case of a possible asbestos contamination a histological clarification should therefore be performed. In this case, pleural plaques in X-rays or CT are indicative (Matthys 2008).

In the case of benign tumours, complete resection is sufficient, but on the other hand it should be carried out without fail, as there is expressive growth and, on the other hand, spinal cord proximity could lead to a possible paraplegia (Matthys 2008).

A special form is the benign pleural mesothelioma. In this case, special care should be taken during surgical removal to ensure that the stem is rich in vessels. Stems are usually found in tumors with a diameter of more than 8 cm.

If it is a malignant mesothelioma, therapeutic measures are often only palliatively possible. In this case, surgery, radiation and chemotherapy are recommended as single measures or in combination. For the prognostically more favourable mesotheliomas, which originate from the epithelial cells, the combined treatment in the form of a pleuropneumectomy, neoadjuvant or adjuvant chemotherapy and possibly also radiotherapy is recommended (Steinbeck 2005).

The therapy of secondary pleural tumours is always purely symptomatic.

In the case of benign pleural mesotheliomas, consistent tumor aftercare is important, since recurrences after a period of 17 years have already been described in the literature (Schumacher 1998).

The prognosis of malignant mesotheliomas is poor with an average survival time of 5 - 10 months. Somewhat more favourable is the prognosis of epithelioid pleural mesotheliomas. Here, a 5-year survival time of approx. 30 % is given (Steinbeck 2005).

Insurance medical aspects

Corresponding diseases of the pleura should immediately be reported to the professional association or the state industrial doctor. BK number 4103 stands for asbestos-associated lung and pleural diseases and BK number 4105 for asbestos-associated mesothelioma of the pleura, pericardium and peritoneum (Fisseler-Eckhoff 2015).

It is advisable to inform the relevant professional association each time a malignant pleural mesothelioma is diagnosed for the first time, as the disease is almost exclusively (up to 90%) caused by asbestos (Craighead 2011).

Insurance medical aspects

Corresponding diseases of the pleura should immediately be reported to the professional association or the state industrial doctor. BK number 4103 stands for asbestos-associated lung and pleural diseases and BK number 4105 for asbestos-associated mesothelioma of the pleura, pericardium and peritoneum (Fisseler-Eckhoff 2015).

It is advisable to inform the relevant professional association each time a malignant pleural mesothelioma is diagnosed for the first time, as the disease is almost exclusively caused (up to 90%) by asbestos (Craighead 2011).

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