Giant solitary fibrous tumour of the pleura an unpredictable entity: case series and literature review

Abstract

A small proportion of tumours can undergo malignant transformation. We report a case series of five patients diagnosed with giant solitary fibrous tumours of the pleura. These cases highlight the unpredictable nature of this disease process, with significant variability in clinical course observed, from indolence to aggressive progression. Three patients were found to have malignant disease on explant, with two of these having preoperative imaging and histology suggesting benign pathology. This finding emphasises that accurately differentiating between benign and malignant disease on imaging and/or biopsy has low specificity and sensitivity and cannot be relied upon in guiding the management of these tumours. Patients with solitary fibrous tumours of the pleura should be managed cautiously, owing to the unpredictable and potentially aggressive clinical course. We would advocate the position that all patients with solitary fibrous tumours of the pleura should be managed as if they have malignant disease. Prolonged follow-up is required due to the risk of disease recurrence, even in patients with benign disease.

Keywords: Giant solitary fibrous tumour of the pleura; Malignant transformation; Pleural tumour; Solitary fibrous tumour.

Figure 1

Transverse and coronal computed tomography of patient 4, demonstrating the significant progression between (a) presentation and (b) surgery.

Figure 2

Chest radiograph and computed tomography (CT) of patient 5, demonstrating the aggressive clinical course in this patient. Serial chest radiographs demonstrate significant enlargement of the lesion (a–b). Significant increase in volume of disease can be seen over the 4-week period between diagnostic imaging (c) and preoperative CT-positron emission tomography confirming radioisotope avidity (standardised uptake value 10) suggestive of malignant transformation (d).

Figure 3

Histopathology: (a) Low power view of a benign solitary fibrous tumour (patient 2). (b) CD34 immunostain showing strong, diffuse positivity in keeping with the diagnosis. (c–d) Core biopsy of a large left sided upper lobe lung/pleural mass (patient 4). High magnification of the core biopsy showing a bland spindle cell tumour with a whorled architecture, scarce mitoses and no significant cytological atypia favouring a benign solitary fibrous tumour. (e–f) Section from the resected tumour of the same patient, appearing malignant at surgery. High magnification showing large atypical epithelioid cells with numerous mitoses, morphologically different from the core biopsy appearance and in keeping with a malignant transformation. All images haematoxylin and eosin stained unless otherwise stated.