Intrapulmonary Solitary Fibrous Tumors – A Clinicopathologic Analysis of 25 Cases.
Nagarjun Rao, Giovanni Falconieri, Cesar Moran, Thomas Colby, Hector Cohen, Saul Suster. Medical College of Wisconsin, Milwaukee; MD Anderson Cancer Center, Houston, TX; Mayo Clinic, Scottsdale, AZ; S. Maria della Misericordia General Hospital, Udine, Italy; Western Galilee Hospital, Naharia, Israel
Background: Solitary fibrous tumor (SFT) was originally described arising in the pleura; later recognized to be ubiquitous in origin. SFT arising within lung has been reported only sporadically, and is therefore not well recognized. Majority of SFT in all locations are benign; a small proportion are aggressive. Although several features have been associated with such behavior, the biology of these tumors remains somewhat unpredictable. For intrapulmonary SFT, the problem is compounded by its relative rarity. This study comprises 25 cases of intrapulmonary SFT. To our knowledge, this is the largest series of this entity, with long term clinical follow up.
Design: Twenty five (25) cases of intrapulmonary SFT form the basis of this study. Clinical, radiologic and pathologic findings were evaluated to include those cases conclusively intraparenchymal in location. Aggressive histologic features including mitoses, atypia and necrosis were particularly assessed. Immunohistochemical stains including CD34, CD99, Cytokeratin AE1/AE3, EMA, SMA, bcl-2, MIB-1, Calponin, and Vimentin were performed on 19 cases. Clinical follow up was available in 19 cases, with long term follow up (> 5 years) available in 5 patients.
Results: 2/25 patients had needle core biopsies; 23/25 had resections. 6/23 resected tumors were > 10 cm in size. 3/6 tumors > 10 cm in size had > 10 mitoses/10 hpf with accompanying necrosis. 5 patients had long term follow up (> 5 years) – 2 alive and well at 13 and 14 years respectively; 2 dead of metastatic disease at 5 and 7 years respectively; 1 patient alive with chest wall metastases at 5 years. A 6th patient was dead of metastatic disease at 4 years. Of 6 patients with tumors > 10 cm, long term follow up was available in two patients – 1 alive and well at 14 years; other patient had chest wall metastases. Of 3 patients dead of metastatic disease; 1 patient had high grade sarcoma at presentation with focal classic SFT areas (CD34 focally positive); and 2 patients had classic SFT at presentation (CD34 positive), with high grade sarcoma at autopsy (retaining CD34 positivity).
Conclusions: Intrapulmonary SFT is a rare entity. This series of 25 cases with significant follow up suggests that there are no reliable predictors of behavior. Regardless of histologic features; close clinical follow up appears to be the most prudent course of action at this time.
Tuesday, March 1, 2011 1:00 PM
Poster Session IV # 285, Tuesday Afternoon