Intrathoracic solitary fibrous tumor: a report of 3 cases and review of the literature

Abstract

Objective

The aim of this study was to investigate the imaging findings of intrathoracic solitary fibrous tumor (SFT), so as to improve its diagnosis and differential diagnosis.

Methods

The clinical, imaging and pathological data of three intrathoracic SFTs confirmed by surgical pathology were analyzed retrospectively. There three cases all received spiral CT plain scan and enhanced scan, among which two multi-planar reformation (MPR) and one MR plain scan. And literatures were reviewed to investigate the imaging findings of intrathoracic SFT.

Results

The three intrathoracic SFT located at intra-pulmonary, oblique fissure pleura and posterior chest wall visceral pleura, respectively. All were solitary masses. One case was a peripheral lung mass at dorsal segment of left lower lobe which CT plain scan showed as a soft tissue mass well circumscribed, enhanced scan showed that there were enhanced clustered, lineal small vascular signs in the mass during arterial phase, delayed scanning displayed that the mass showed heterogeneous enhancement and parts of solid content showed gradual enhancement, and there were shorter T₁ signals on MRI T₁WI, map-like high-low mixed signals on T₂WI, mainly with short T₂ signals. One case was an oblique fissure mass which plain scan showed as a homogeneous soft tissue mass with oval in shape and smooth edge, and enhanced scan showed moderate homogeneous enhancement. One case was a mass localized at posterior chest wall visceral pleura which CT plain scan showed as a heterogeneous mass, and enhanced scan showed that there was slight ring-like enhancement, large non-enhancing necrosis area in the mass and facing vessels in the vicinity region. All these three cases had no hilar and mediastinal lymphadenectasis. Operation and pathology results showed that the mass was well circumscribed, with capsule or false capsule. Under microscope, tumor cells were long fusiform, presenting bundle, turbulence or irregular arrangement. Hypocellular and hypercellular area appeared alternately, with interspersed coarse scar-like collagen fibers with hyalinization. There were hemangiopericytoma-like structures under parts of visual fields. There were bronchiole and alveolar epithelium in the legion at dorsal segment of left lower lobe in one case. The results of immunohistochemistry showed that the expressions of CD34 or CD99, Bcl-2 and vimentin were all strong positive.

Conclusion

Intrathoracic SFT might be rare, which imaging findings could have relative characteristic features and diagnosis must depend on histopathology and immunohistochemistry examination.