Received 09-02-2006; Accepted 04-03-2006

Author and address for correspondence:

Vojkan Stanić, MDClinic for Thoracic SurgeryMilitary Medical AcademyCrnotravska 17BeogradSerbia & MontenegroTel: +381 63 287621E-mail: vojkans@yubc.net

Journal of BUON 11: 241-244, 2006© 2006 Zerbinis Medical Publications. Printed in Greece

CLINICAL CASE

Solitary fi brous tumors of the pleura

V. Stanić1, T. Vulović2, S. Ilić3, D. Stamenović11Clinic for Thoracic Surgery, Military Medical Academy, Beograd; 2Clinic for Anesthesiology, Clinical Center, Kragujevac; 3Instituteof Pathology, Military Medical Academy, Beograd, Serbia & Montenegro

Summary

Two cases of female patients with solitary fibrous tumor of the pleura are described. Chest radiography and computed tomography showed the presence of a giant mass with inhomogeneous density in the hemithorax in both cases. Transthoracic needle biopsy of the masses showed benign fi brous tissue. Both patients underwent thoracotomy. The tumors arose from the visceral pleura, were peduncular, appeared well-circumscribed with exterior surface smooth,

fi rm and multinodular. The size of tumors were 16×11×6 cmand 15×11×4.5 cm, weighed 650 g and 573 g and both weresuccessfully resected. The pathological diagnosis was benignsolitary fi brous tumor of the pleura. Seven years after theoperations the clinical condition and chest radiography arenormal in both women.

Key words: pleura, solitary fi brous tumor, surgical treat-ment, thoracic surgery

Introduction

Solitary fibrous pleural tumors are very rare. They are also designated as localized mesotheliomas of the pleura, either benign or malignant. The fi rst description of the pathological features of pleural me-sotheliomas and their division in localized and diffuse tumors were given by Klemper and Rabin in 1937. Murray and Stout in 1942 found that these tumors originate from mesothelial cells.

Their histological structure can vary greatly. In the most common form a mixture of connective tis-sue and fi broblast-like cells dominates, but there are also forms which resemble haemangiopericytoma,

leiomyoma or neurofi broma. The mixed form is seenin about 40% of the cases. These tumors can be bothbenign and malignant.

Benign tumors grow on a pedicle attached to vis-ceral pleura. Most commonly their diameter does not exceed 10 cm. On very rare occasions they are largeenough to occupy a hemithorax. Histologically, thereexists relative acellularity and rare mitoses.

Malignant localized mesotheliomas grow as ses-sile tumors from parietal, mediastinal and diaphrag-matic pleura. They reach greater dimensions thanbenign mesotheliomas. Histologically, they show atendency toward greater cellularity, pleomorphism and more frequent mitoses.

Case presentations

Case 1

A 43-year-old female was admitted to the hos-pital because of hypertrophic pulmonary osteoar-thropathy with predominant pain in hands and wrists.Radiographic fi ndings showed a massive inhomoge-neous shadow in the right hemithorax in continuitywith the mediastinal shadow. A thoracic CT showed a

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clearly defi ned, well marked tumor without infi ltrative characteristics (Figure 1). The patient refused bron-choscopy. Her pulmonary function indicated moderate restrictive disorder of ventilation. Needle lung biopsy was inconclusive. The patient underwent thoracotomy, during which a tumor measuring 16×11×6 cm was seen in the lower part of the hemithorax, connected with the inferior lobe with two separate peduncles. The tumor was clearly demarcated, with rough surfaces and was completely removed. It weighted 650 g. The postoperative period was uneventful and the patient is now in yearly follow up without signs of recurrence for 7 years.

Case 2

A 48-year-old female was admitted to the hos-pital with exertional dyspnea, anterior chest pain, and fever (39.2o C). She had lost more than 5 kg in 3 months.

Plain chest radiography showed giant pleural effusion on the left with compressive atelectasis of the surrounding lung parenchyma. A thoracic CT also showed compressive atelectatic changes in the lower left lobe. Pulmonary function indicated moderate re-strictive ventilation disorder. Bronchoscopy revealed extramural compression in the left posterobasal segmental bronchus, while cytology was not positive for malignancy. Needle biopsy of the pleura and lung did not provide diagnosis. Hence, the patient under-

went thoracotomy during which a tumor measuring15×11×4.5 cm was seen, connected by a pedunclewith the visceral pleura of the lower lobe. The tumor was completely resected and weighted 573 g (Figure2). The postoperative period was complicated withempyema, for which the patient underwent a second thoracotomy after resolution of the empyema, in order to decorticate the lung. The patient is now in yearlyfollow up without signs of recurrence for 7 years.

Pathological findings

The tumors appeared well-circumscribed withexterior surface smooth, fi rm and multinodular. Oncross-section they appeared predominantly solid,nodular and grey with myxoid areas, hemorrhage and cystic degeneration.

Tissue samples were formalin-fi xed, paraffi n-embeded and stained with haematoxylin-eosin, PASand Masson thrichrom method. Immunohistochemi-cal study was performed on deparaffi nized sections,using the avidin-biotin peroxidase complex (ABC)(DAKO Cat.No. K0355) as a visualisation system.The following DAKO primary antibodies were used:Monoclonal Mouse Anti Human Vimentin Cat. No.M7025; Monoclonal Mouse Anti Human CD-34 Cat.No. M0824; Monoclonal Mouse Anti Human ActinCat. No. M0635; Monoclonal Mouse Anti HumanDesmin Cat. No. M 0760; Polyclonal Rabbit Anti S-100 protein Cat. No. Z0311; Monoclonal Mouse Anti

Figure 1. Thoracic CT in case 1. Clearly defined, well demarkated tumor without infiltrative characteristics in the posterior part of the right hemithorax.

Figure 2. Macroscopic appearance of the tumor in case 2. Solid tumor measuring 15x11x4.5 cm connected by a peduncle with thevisceral pleura of the lower right lobe.

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Human Cytokeratin Cat. No. M0821; Monoclonal Mouse Anti-Human Epithelial Membrane Antigen Cat. No. M0613; and Polyclonal Rabbit Anti Human Keratin Cat. No Z 0622. Appropriate positive and negative controls were used.

Microscopically, the tumors were exclusively composed of spindle cells with uniform plump ve-sicular nuclei or elongated hyperchromatic nuclei, poorly defi ned pale eosinophilic cytoplasm, admixed with collagen fi bers and arranged in short, ill-defi ned fascicles. In others zones the cells were arranged ran-domly in what has been described as a “patternless pattern”. Several regions contained both dense and less dense cellular areas with a myxoid appearance or dense coarsely collagenization or ischemic necrosis. These cells showed no pleomorphism and mitoses were rare. Immunohistochemical study showed that the spindle cells reacted only with antibodies directed against vimentin (Figure 3) and CD34.

Discussion

Solitary fi brous tumor of pleura is a rare disease equally represented in both sexes. It may appear at any age group, but it is more frequent between the 5th and 8th decade of life [1-4].

According to the literature, the most frequent symptoms of this tumor (cough, dyspnea and pain) are present in about 50% of cases. Fever, hypertrophic pulmonary osteoarthropathy and haemoptysis may also emerge [2,3,5]. Pleural effusion appears in 8% of the patients.

Bronchial compression and atelectasis are fre-quently present along with large tumors. Plain chest

radiography usually cannot distinguish solitary fi broustumor of the pleura from other lung tumors, while thecontribution of thoracic CT is rather moderate [4].

Although preoperative diagnosis is diffi cult [6],solitary fi brous tumor of the pleura can be diagnosed by transthoracic needle biopsy of the lung. It is a valid tool for diagnosis of peripheral lung tumors. Diagnosisis accomplished immunohistochemically (keratin-negative and vimentin-positive in 100% of cases, and CD34 antibody-positive in about 80% of cases) [2].

Cytological, immunohistochemical and ra-diographic fi ndings could be suffi cient for making apreoperative diagnosis [7].

Two cases presented in this paper showed typi-cal characteristics of benign localized solitary fi broustumor of the pleura in terms of clinical, radiological,morphological and histopathological findings and therapeutic approach.

Conclusion

Surgical resection presents the treatment of choice for solitary fi brous tumor of the pleura. Sincethese tumors arise from the visceral pleura and are usu-ally peduncular, surgical intervention is very simple,no matter of tumor size.

However, after surgical resection one cannot safely predict the tumor behavior in the future, regard-less of its histological appearance [8,9]. Relapses aremore frequent with sessile and locally invasive tumors[6], something indicating continuous patients’ followup. Okike et al. described relapse in 2 of 58 benigncases of solitary fi brous tumor of the pleura [5] and Perrot et al. [10] described relapse of malignant me-sothelioma after resection of benign solitary fi broustumor of the pleura.

References

1. Rusch VW. Mesothelioma and less common pleural tumors.In: Pearson FG, Cooper JD (eds): Thoracic Surgery. NewYork, Churchill-Livingstone, 2002, pp 1241-1260.

2. Briselli M, Mark EJ, Dickersin L. Solitary fi brous tumors of the pleura. Eight new cases and review of 360 cases in theliterature. Cancer 1981; 47: 2678-2689.

3. England DM, Hochholzer L, McCarthy MJ. Localized benign and malignant fi brous tumors of the pleura. A clini-copathological review of 223 cases. Am J Surg Pathol 1989;13: 640-658.

4. Shields TW, Yeldandi AV. Localized fi brous tumors of thepleura. In: Shields TW, LoCicero J, Ponn RB (eds): GeneralThoracic Surgery. Philadelphia, Lippincot Williams and Wilkins, 2000, pp 757-767.

Figure 3.Solitary fibrous tumor with uniform vimentin expression (arrows; ABC method × 100).

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5. Okike N, Bernatz PE, Woolner LB. Localized mesothelioma of the pleura: benign and malignant variants. J Thorac Car-diovasc Surg 1978; 75: 363-372.

6. Suter M, Gebhard S, Boumbhar N, Peloponisios N. Localised fi brous tumours of the pleura: 15 new cases and review of the literature. Eur J Cardiothorac Surg 1998; 14: 453-459.

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8. Cardillo G, Facciolo F, Cavazzana A, Capece G. Localized (solitary) fi brous tumors of the pleura: an analysis of 55patients. Ann Thorac Surg 2000; 70: 1808-1812.

9. Rusch VW, Venkatraman ES. Important prognostic factorsin patients with malignant pleural mesothelioma, managed surgically. Ann Thorac Surg 1996; 68: 1799-1804.

10. Perrot M, Kurt AM, Robert JH, Borisch B. Clinical behavior of solitary fi brous tumors of the pleura. Ann Thorac Surg1999; 67: 1456-1459