Current Problems in Cancer: Case Reports (Jun 2022)
A case of multiple metastases from a primary renal solitary fibrous tumour; The uncertain long road.
Abstract
Solitary fibrous tumours (SFT) comprise a rare subset of soft tissue tumours of mesenchymal origin accounting for fewer than 2% of all soft tissue tumours, most commonly arising in the pleura (Davanzo et al., 2018). The kidney as a primary site is extremely uncommon (Znati et al., 2007). The majority of SFT's exhibit indolent behaviour although local or distant recurrence may occur in 10-30% of cases (Fletcher, 2013). Those with malignant features such as mitotic rate more than 4 mitoses per 10 high power fields (>4/10 HPF) represent a much greater risk of recurrence (England, Hochholzer and McCarthy, 1989). Here we present an unusual case of a patient who presented with multiple metastatic recurrences of a SFT of primary renal origin spanning over 2 decades. The original tumour was small with benign features and clear margins of resection. 15 years later she presented with a pulmonary recurrence which was again resected with clear margins. A further pulmonary metastasis with bland features was resected 5 years later. Given such prognostic indicators our patient not surprisingly enjoyed a long disease-free interval of 15 years. Sequential resection of localized metastases provided further survival benefit of 5 years until the development of disseminated metastatic disease. Our case highlights the unpredictable nature of SFT's even in the setting of such favourable prognostic features. We discuss recent advances in the management of metastatic SFTs. Although the data regarding the use of systemic therapy in this setting is ill-defined, there remains sufficient evidence to suggest potential benefit in this case.
