This rare tumor is most frequently diagnosed as an incidental finding on a routine chest x-ray or for evaluation of an unrelated disease. These tumors usually arise from the visceral pleura with a lesser percentage (about 20-40%) arising from the parietal pleura. In cases which are symptomatic, patients present with cough, chest pain, and shortness of breath (dyspnea). If hemoptysis occurs, a malignant tumor should be suspected. The benign tumors are slow growing and compress adjacent structures but usually do not invade. On microscopic sections, the pattern has been described as a mixture of spindle cell patterns, sometimes a patternless pattern. All of the tumors are united by a common staining pattern for the CD34 immunoperoxidase stain. This pattern may be found in similar tumors which have been reported in nearly every organ and location and have been termed solitary fibrous tumors. Although malignant tumors may occur, benign tumors are far more common outnumbering the malignant tumors by a ratio of 4 to 1.
SYNONYMS Solitary fibrous tumor of the pleura INCIDENCE
2.8/100,000 patient admissions at the Mayo Clinic
6-7th decades peak
Range 5-87 years
SEX (M:F) Equal
EPIDEMIOLOGIC ASSOCIATIONS CHARACTERIZATION Asbestos exposure Possible association
GROSS APPEARANCE/CLINICAL VARIANTS CHARACTERIZATION General
Tumor may be pedunculated and connected to the pleura surface by a fibrous band
Cut surface is white and whorled with occasional foci of hemorrhage
HISTOLOGICAL TYPES CHARACTERIZATION GENERAL Two predominant patterns have been described but may coexist VARIANTS DIFFUSE SCLEROSING Extensive fibrous stroma SOLID SPINDLE CELL MALIGNANT TUMORS Malignant tumors have greater cellularity with an infiltrative growth pattern, variation in nuclear size and shape, prominent nucleoli, and increase in mitotic activity to usually >4/10 hpf Malignant Solitary Fibrous Tumor of the Pleura With Liposarcomatous Differentiation
Arch Pathol Lab Med 2001;125:406–409
66-year-old, white man with a large, solid right pleural mass that measured 13.5 × 10.3 × 8.5 cm
Numerous adipocytes mixed with typical lipoblasts were seen scattered throughout portions of the tumor
Immunohistochemistry revealed the tumor cells were strongly positive for CD34 and vimentin and negative for cytokeratin, desmin, smooth muscle actin (IA4), and S100
SPECIAL STAINS/IMMUNOPEROXIDASE/OTHER CHARACTERIZATION Special stains Immunoperoxidase CD34 positivity is the hallmark-ranges from 80-100% of cases
Present in both benign and malignant tumors
CD99 Positive in the majority of tumors but only rarely in sarcomatoid mesotheliomas bcl-2 Positive in both pleural and non-pleural tumors but not in mesotheliomas Vimentin Positive
DIFFERENTIAL DIAGNOSIS KEY DIFFERENTIATING FEATURES Spindle cell mesothelioma Biphasic or monophasic synovial sarcomas Smooth muscle tumors Sarcomatoid carcinoma
PROGNOSIS AND TREATMENT CHARACTERIZATION PROGNOSIS May have an unpredictable course Pedunculated tumors May have better prognosis Evidence of invasion of lung parenchyma, chest wall or diaphragm Poor prognosis Significant cellular atypia, increased mitotic activity, extensive necrosis Poor prognosis Recurrence Local recurrence has been reported as long as 17 years after initial complete resection TREATMENT
Complete resectability is most important determinant of survival
More radical surgical may be needed for malignant tumors
Ann Thorac Surg 1000;67:1456-1459
Post-operative radiotherapy and/or chemotherapy
Solitary fibrous tumour of the pleura: surgical treatment.
Rena O, Filosso PL, Papalia E, Molinatti M, Di Marzio P, Maggi G, Oliaro A.
Department of Thoracic Surgery, S. Giovanni Battista Hospital, University of Torino, v. Genova 3, 10126 Torino, Italy.
Eur J Cardiothorac Surg 2001 Feb;19(2):185-9 Abstract quote
OBJECTIVE: Solitary fibrous tumours (SFT) of the pleura are rare tumours originated from the mesenchimal tissue underlying the mesothelial layer of the pleura. This tumours present unpredictable clinical course probably related to their histological and morphological characteristics.
METHODS: Twenty-one patients affected by SFT of the pleura were referred to us for surgical resection from September 1984 to April 2000. They were 15 males and six females with median age of 51 (range 15--73) years. Nine patients (43%) were symptomatic and predominant clinical symptoms or signs were dyspnoea (19%), coughing (14.3%), chest pain (28.5%), finger clubbing (14.3%) and hypoglycaemia (14.3%). Hypoglycaemia was related to a pathological incretion of insulin-like growth factor 2 by the tumour. Chest radiograph and computed tomography of the chest revealed intra-thoracic homogeneous sharply delineated round or lobulated mass sometimes associated with ipsilateral pleural effusion (19%) or causing pulmonary atelectasis with opacification of the complete hemithorax (19%). Surgical excision required 14 posterolateral thoracotomies, six anterior thoracotomies and one video-assisted thoracoscopy. Thirteen tumours arose from visceral pleura and wedge resection was performed, seven tumours arose from parietal pleura and extrapleural resection was carried out without any chest-wall resection, one tumour growth within the upper left lobe and required lobectomy. Tumours weighted from 22 to 1942 g and measured from 22x12x8 to 330x280x190 mm. At cut section seven cases (34%) revealed focal necrosis and hemorrhagic zones and on light microscopy six cases (28.5%) were characterized by high mitotic count: characteristics related with uncertain clinical behaviour. Immuno-histochemical reactions were in all cases positive for CD34.
RESULTS: In all our patients resections were complete. Paraneoplastic syndromes like hypoglycaemia and clubbing receded after surgery. No intraoperative or perioperative medical or surgical complications occurred. Median chest-drain duration timed 3 (range 2--5) days and median hospital stay was 5 (range 4--7) days. Perioperative mortality rate was 0%. Median follow-up was 68 (range 2--189) months: during this period patients were submitted to chest X-ray with 6-months interval to evaluate possible local recurrence. Only one patient experienced tumour recurrence after 124 months follow-up: the tumour was suspected after observation of finger clubbing. The tumour was detected and excised by redo-thoracotomy.
CONCLUSIONS: Surgical resection of benign solitary fibrous tumours is usually curative, but local recurrences can occur years after seemingly adequate surgical treatment. Malignant solitary fibrous tumours generally have a poor prognosis. Clinical follow-up and radiological follow-up are indicated for both benign and malignant solitary fibrous tumours.
Adv Anat Pathol 2000;7:327-340.
Last Updated 11/22/2001
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