Article

Solitary fibrous tumor on needle biopsy and transurethral resection of the prostate: a clinicopathologic study of 13 cases.

Department of Pathology, The Johns Hopkins Hospital, Baltimore, MD 21231, USA.
American Journal of Surgical Pathology (Impact Factor: 4.59). 06/2007; 31(6):870-6. DOI: 10.1097/01.pas.0000213416.23256.71
Source: PubMed

ABSTRACT One of the least commonly encountered spindle cell tumors seen on prostatic needle biopsy or transurethral resection (TUR) of the prostate is solitary fibrous tumor (SFT). We studied 13 cases of SFTs identified on either prostate needle biopsy (n=9) or TUR of the prostate (n=4). Mean patient age at diagnosis was 63 years (range: 46 to 75 y; median: 65 y). Twelve men presented with urinary tract symptoms and 1 patient was biopsied during work-up of bone metastases. Ten cases were SFTs originating in the prostate, 2 cases arose between the prostate and rectum extending into the prostate (n=2), and 1 case was a pelvic mass without infiltration of the prostate. In 9 cases, a complete tumor resection was attempted by cystoprostatectomy (n=2), radical prostatectomy (n=4), pelvic exenteration (n=2), or pelvic tumor resection (n=1). Enucleation (n=1) and TUR (n=1) were performed in 2 other cases. Tumor sizes ranged from 8.5 to 15 cm in 7 radically resected cases. Mitotic rates were 3 to 5 per 10 high power fields in 5 cases, with the remaining cases having either rare (n=4) or no mitoses (n=4). Seven cases demonstrated areas of necrosis. Based on a combination of increased cellularity, mitotic activity, necrosis, nuclear pleomorphism, and infiltrativeness, 4 prostatic SFTs were malignant, 4 were benign, and 2 were borderline. Of the 3 non-prostatic SFTs, 1 was malignant and 2 were borderline. All tumors but 1 were immunoreactive for CD34 (n=12). Material for additional immunohistochemistry was available for the majority of cases with positive stains for Bcl-2 (11/11), CD99 (7/10), beta-catenin (5/10), and c-kit (0/11). Three SFTs demonstrated >or=10% p53 immunoreactivity including 1 tumor with 50% positivity; and 3 cases had Ki-67 rates of >or=20%. Although all SFTs were initially clinically considered to be of prostatic origin, some of the cases arose in the pelvis with secondary involvement of the prostate. Approximately 50% of prostatic SFTs were malignant. Even in the prostatic and nonprostatic SFTs with no overt malignant features, sometimes it was necessary to remove the prostate and in some instances the adjacent organs because of the large size of the tumors. SFTs must be differentiated from other spindle cell neoplasms of the prostate especially from gastrointestinal stromal tumors that may arise from the rectal wall with invasion of the prostate or from the region between the rectum and the prostate.

0 Followers
 · 
74 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: Solitary fibrous tumors (SFTs) of the prostate are a rare type of spindle cell neoplasm that can demonstrate either a benign or malignant phenotype. SFTs represent a clinical challenge along with other spindle cell lesions of the prostate in terms of both diagnosis and treatment. The present study shows, for the first time, that SFTs of the prostate and other organs can comprise a mixed population of fibroblast, myofibroblast, and smooth muscle cell types. The highly proliferative component demonstrated a fibroblastic phenotype that readily underwent myofibroblast differentiation on exposure to profibrotic stimuli. Consistent with other recent studies, the prostatic SFTs demonstrated NAB2-STAT6 gene fusions that were also present in the fibroblast, myofibroblast, and smooth muscle cell types of the SFT. The results of these studies suggest that benign and malignant prostatic tumors of mesenchymal origin may be distinguished at the molecular and cellular levels, and that delineation of such defining characteristics may help elucidate the etiology and prognosis of such tumors.
    American Journal Of Pathology 01/2014; DOI:10.1016/j.ajpath.2013.11.024 · 4.60 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Increased FDG uptake in the prostate can be caused by both benign and malignant conditions. The purpose of this pictorial review is to demonstrate a spectrum of prostate lesions which can show increased FDG uptake on PET/CT imaging. Various prostate lesions can show increased FDG uptake. Knowledge of the uptake characteristics of these lesions may be helpful for increasing diagnostic accuracy.
    Abdominal Imaging 03/2014; 39(4). DOI:10.1007/s00261-014-0114-0 · 1.73 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Most solitary fibrous tumors (SFTs) are cured by complete resection, but many recurrent and metastatic SFTs do not respond to treatment and are fatal. Malignant histology, defined by England's pathologic criteria, is strongly associated with recurrence, but some benign SFTs still behave aggressively. Several studies have suggested that extrathoracic SFTs have a worse prognosis. We reviewed thoracic and extrathoracic SFTs from our institution to determine if extrathoracic location is associated with recurrence, independent of malignant histology. With IRB approval, we retrieved patient pathology reports from the Johns Hopkins Surgical Pathology database between 1991 and 2011 and included 83 SFT patients in our analysis. Patient history and outcomes were obtained from the medical record and primary care physicians. Predictors of recurrence were analyzed by univariate and multivariate analysis and survival determined by the Kaplan-Meier method. Of the 83 patients, 59 had extrathoracic SFTs in neurologic (n = 24), extremity or head/neck (n = 13), or visceral/intraabdominal (n = 22) sites. A total of 74 SFTs were classified benign and 9 as malignant. Of the 14 recurrences, 13 occurred in extrathoracic SFTs; only 7 were classified as malignant. Multivariate analysis confirmed that malignant histology had the strongest association with recurrence, but extrathoracic location also independently predicted recurrence. A total of 20 benign SFTs possessed 1 or more of England's criteria but to an insufficient degree for malignant classification. These "borderline" SFTs were more likely to recur than benign SFTs without these features. Extrathoracic and "borderline" SFTs with any of England's criteria have a higher risk of recurrence.
    Annals of Surgical Oncology 09/2013; 20(13). DOI:10.1245/s10434-013-3241-x · 3.94 Impact Factor