Serdar Balcı

Diseases and Tumors of the Mediastinum and Pleura

Serdar BALCI, MD

Pleural Lesions

Primary intrapleural bacterial infections

Primary neoplasm, malignant mesothelioma

A secondary complication of an underlying pulmonary disease

Pleural Effusion and Pleuritis

Causes of pleural exudate

Acute serofibrinous pleuritis related to pneumonia

Autopsy Pathology: A Manual and Atlas

Suppurative pleuritis


Autopsy Pathology: A Manual and Atlas

Pleural effusions


Complications of pneumothorax


Collection of whole blood

Ruptured intrathoracic aortic aneurysm

In contrast with bloody pleural effusions, the blood clots within the pleural cavity

Autopsy Pathology: A Manual and Atlas


Malignant Mesothelioma

Cancer of mesothelial cells

Usually arising in the parietal or visceral pleura

Less commonly, in the peritoneum and pericardium

Related to occupational exposure to asbestos in the air

50% of persons with this cancer have a history of exposure to asbestos

Shipyard workers, miners, insulators

Living in proximity to an asbestos factory, a relative of an asbestos worker

The latent period for developing malignant mesothelioma is long

25-40 years after initial asbestos exposure

With combination of cigarette smoking, asbestos exposure greatly increases the risk of lung carcinoma

Autopsy Pathology: A Manual and Atlas

Malignant mesothelioma

Autopsy Pathology: A Manual and Atlas

Malignant mesothelioma

Thick, firm, white pleural tumor

Ensheathes lung

Robbins Basic Pathology

Distant metastases are rare

Directly invade the thoracic wall or the subpleural lung tissue

Mesothelioma patterns

Malignant mesothelioma

**Papillary formations and desmoplastic stromal reaction. **

Rosai and Ackerman’s Surgical Pathology


**Metastatic tumor involving the parietal pleura **

Autopsy Pathology: A Manual and Atlas

Rosai and Ackerman’s Surgical Pathology



Tumors of thymic epithelial cells

Typically also contain benign immature T cells (thymocytes)

Tumors that are cytologically benign and noninvasive

Tumors that are cytologically benign but invasive or metastatic

Tumors that are cytologically malignant (thymic carcinoma)

Clinical Presentation of Thymomas

40% mass effect

30-45% myasthenia gravis

Others incidentally during imaging studies or cardiothoracic surgery

Diseases Associated with Thymoma

**Myasthenia gravis **


Pure red cell aplasia

Graves disease

Pernicious anemia


Cushing syndrome

Autoimmune Diseases Associated with Thymoma

Thymocytes within thymomas give rise to long-lived CD4+ and CD8+ T cells

Cortical thymomas rich in thymocytes are more likely to be associated with autoimmune disease

Abnormalities in the selection or “education” of T cells maturing within the environment of the neoplasm contribute to the development of diverse autoimmune disorders


**Gross appearance of a thymoma showing distinct multinodularity. There is focal cystic change in the larger nodule. **

Noninvasive thymomas

Composed of medullary-type epithelial cells

Mixture of medullary and cortical type epithelial cells

The medullary type epithelial cells are elongated or spindle-shaped

There is usually a sparse infiltrate of thymocytes, which often recapitulate the phenotype of medullary thymocytes

Benign thymoma (medullary type):

Neoplastic epithelial cells in a swirling pattern and have bland, oval to elongated nuclei with inconspicuous nucleoli. Few small, reactive lymphoid cells are interspersed.

Invasive thymoma

Tumor that is cytologically benign but locally invasive

Much more likely to metastasize

Epithelial cells are most commonly of the cortical variety, with abundant cytoplasm and rounded vesicular nuclei, and are usually mixed with numerous thymocytes

Malignant thymoma, type I. The neoplastic epithelial cells are polygonal and have round to oval, bland nuclei with inconspicuous nucleoli. Numerous small, reactive lymphoid cells are interspersed.

Thymic carcinoma

**Gross appearance of thymic carcinoma (type C thymoma). The tumor is invasive and shows foci of necrosis. **

thymic carcinoma