Large solitary fibrous tumor of the pleura

An elderly female patient referenced to the emergency department of our institution complaining of shortness of breath and left side chest pain.

Chest radiograph showed a well-defined large lesion in the middle third of the left lung (Fig.1).

Contrast-enhanced CT scan revealed a well-defined, lobulated, pleural-based, solid mass, measuring 9x8 cm, with heterogeneous enhancement, and areas suggestive of recent bleeding (Fig.2). No hilar or mediastinal lymphadenopathy were detected.

Biopsy revealed the presence of inflammatory and fibrotic cells, and the patient was referred for surgery, with no other adjuvant treatment being performed. The final pathological diagnosis was of a solitary fibrous tumour.

Postoperative chest radiograph, performed 1 month after surgery, showed good end result, with no signs of residual tumour and only minor left lung volume decrease (Fig.3).

Solitary fibrous tumours of the pleura (SFTP) are thought to arise from the non-committed mesenchymal cells  in  the  areolar  tissue  subjacent  to  the mesothelial-lined pleura [1]. SFTP are a rare neoplasm, often benign (80%), predominantly occurring in the sixth and seventh decades of life, affecting both sexes equally [1]. There is no apparent genetic predisposition and no known relationship to any environmental exposure [1,2].

Most patients present with some symptoms, commonly cough, chest pain or dyspnea [1,3]. Hypertrophic pulmonary osteoarthropathy is the most common paraneoplastic syndrome in SFTP, especially in larger tumors ( up to 22%  of patients), and generally resolves after removal of the tumour [2].

Chest radiograph is non-specific, usually revealing a  mass with well-circumscribed margins, located near the lung periphery or in the projection of an interlobar fissure.  The chest CT scan is very important, showing the precise location of the tumor and aiding in surgical planning. SFTP usually appear as well-delineated, lobulated masses with heterogeneous attenuation and contrast enhancement (usually intense due to rich vascularization). It can have areas of myxoid or cystic degeneration, haemorrhage, central necrosis and calcifications (up to 26% of tumours) [1-4].  Rarely chest wall invasion or rib notching can be seen [1]. Magnetic resonance imaging is occasionally used to determine potential invasion of the chest wall [1,3].

The preferred method of treatment of SFTP is surgical resection in both the benign and malignant types. Larger tumours might require a major lung resection such as a lobectomy or, rarely a pneumonectomy. Due to the rarity of these tumours, there are no guidelines for adjuvant therapy [1-4].

SFTP can metastasize, with the pleura being the most common site (75%), followed by lung, liver, bones and peritoneum. Metastases to the brain or chest/abdominal wall are rare [5].

Follow-up for recurrence should include a chest CT every 6 months for the first 2 years since most recurrences, particularly of the sessile malignant tumours,  occur within  24  months of surgery.   However, patients need long-term follow-up (usually yearly CT) due to the possibility of late recurrences (reported as long as 17 years after initial surgery) [1].