data regarding the mode and timing of delivery incases of ongoing brain injury. However, most author-ities believe that the mode of delivery should be basedon obstetric indications. Vaginal delivery appears tobe a safe mode. In our case, cesarean delivery waselected as a result of the multiple partial lobectomiesthe patient underwent and the concern about theongoing increase in intracranial pressure.

In conclusion, brain abscess is a rare but life-threatening complication of pregnancy. Managementof brain abscess for pregnant and nonpregnant pa-tients is the same. It is difficult to conclude that brainabscess could have been avoided in this case. There-fore, it is of paramount importance to educate patientsabout proper oral hygiene before and during preg-nancy to optimize maternal health. By reporting thiscase, we hope to increase awareness among dentists,obstetricians and gynecologists, emergency depart-ment physicians, and primary care physicians of thediagnosis of a brain abscess after dental surgery when

patients present with severe headache, facial swelling,and mental status changes.

REFERENCES1. Gendron R, Grenier D, Maheu-Robert L. The oral cavity as a

reservoir of bacterial pathogens for focal infections. MicrobesInfect 2000;2:897–906.

2. Hollin SA, Hayashi H, Gross SW. Intracranial abscesses ofodontogenic origin. Oral Surg Oral Med Oral Pathol 1967;23:277–93.

3. Pallasch TJ, Slots J. Antibiotic prophylaxis and the medicallycompromised patient. Periodontol 2000;10:107–38.

4. Yang SY. Brain abscess: a review of 400 cases. J Neurosurg1981;55:794–9.

5. Wax JR, Pinette MG, Blackstone J, Cartin A. Brain abscesscomplicating pregnancy. Obstet Gynecol Surv 2004;59:207–13.

6. Lu CH, Chang WN, Lui CC. Strategies for the management ofbacterial brain abscess. J Clin Neurosci 2006;13:979–85.

7. Minassian C, D’Aiuto F, Hingorani AD, Smeeth L. Invasivedental treatment and risk for vascular events: a self-controlledcase series. Ann Intern Med 2010;153:499–506.

8. Giglio JA, Lanni SM, Laskin DM, Giglio NW. Oral health carefor the pregnant patient. J Can Dent Assoc 2009;75:43–8.

Solitary Fibrous Tumors ArisingFrom the Female Pelvis

Thanasak Sueblinvong, MD,Patricia L. Judson, MD, Levi S. Downs Jr, MD,and Peter A. Argenta, MD

BACKGROUND: Solitary fibrous tumor is a rare mesen-chymal tumor reported initially in the pleura but that isnow reported in widely ranging anatomic sites with avariable clinical course. Solitary fibrous tumor arisingfrom the female genital tract is extremely rare and themanagement of this condition is controversial.

CASES: We report three cases of female genital tractsolitary fibrous tumors displaying different clinical behav-iors and review literature with regard to diagnosis, pos-sible prognostic factors, and management of this tumor.

CONCLUSION: The primary treatment of this diseaseshould be surgical. The rarity and disparate clinical man-ifestations of this disease preclude a definitive statement

on use and optimization of adjuvant therapy. Neverthe-less, both pathologic and clinical findings may be usefulin gauging risk and assessing the merits of individualizedadjuvant therapy.(Obstet Gynecol 2011;118:470–4)DOI: 10.1097/AOG.0b013e31821b2037

Solitary fibrous tumor is a rare mesenchymal tumorwith a reported incidence of approximately 2.8

cases per 100,000 people annually.1 Although mostcommonly identified within the pleura of the lung,there are reports of solitary fibrous tumors in a varietyof extrapleural sites, including the breast, orbit, me-ninges, pancreas, liver, renal capsule, parotid gland,spinal cord, and soft tissue. To date, we have identi-fied 13 reports of cases originating from female genitaltract and an additional eight cases arising from thenonreproductive organs of the female pelvis (Table 1;PubMed search of solitary fibrous tumor).2–15

Most solitary fibrous tumors exhibit indolentgrowth and the absence of metastases; however, in12%–22% of cases a more malignant phenotype hasbeen reported. Although wide local excision withoutadjuvant therapy appears appropriate for the former, theideal treatment for the latter remains unclear.15 It is alsounclear whether the observed differences in phenotyperepresent two distinct clinical entities or progressivemanifestations of a single pathologic process.

We report three cases of solitary fibrous tumorreferred to our gynecologic oncology service that repre-

From the Department of Obstetrics, Gynecology and Women’s Health, Divisionof Gynecologic Oncology University of Minnesota, Minneapolis, Minnesota.

Corresponding author: Peter A. Argenta, MD, MMC, 395 420 Delaware StreetSE, Minneapolis, MN 55455; e-mail: argenta@umn.edu.

Financial DisclosureThe authors did not report any potential conflicts of interest.

© 2011 by The American College of Obstetricians and Gynecologists. Publishedby Lippincott Williams & Wilkins.ISSN: 0029-7844/11

470 Sueblinvong et al Solitary Fibrous Tumors in the Pelvis OBSTETRICS & GYNECOLOGY

sent the varied clinical presentation and course of thisdisease. We also review literature with regard to diag-nosis, treatment options, and prognosis of this condition.

CASE 1

The patient is a 54-year-old women who presented to ourservice with recurrent disease. She had initially presented 3years earlier with pelvic discomfort thought to be caused byuterine leiomyomata. During exploratory laparotomy atthat time, a pelvic mass measuring 10�16�9.5 cm wasidentified emanating from the left pelvic peritoneum. Sheunderwent resection of pelvic mass, complete hysterec-tomy, and bilateral salpingo-oophorectomy. The pathologydemonstrated a cellular spindle cell tumor consistent withsolitary fibrous tumor. There were approximately 6–7 mi-toses per 10 high-power fields (hpf) and multiple areas ofcoagulative type necrosis.

No adjuvant therapy was pursued and she was fol-lowed-up clinically for 3 years when she presented to ourservice with increasing right lower quadrant pain and pres-sure. Computed tomography demonstrated a 12�10-cm massextending from pelvis and multiple mesenteric masses rangingfrom 2.7 to 7.3 cm. Neither ascites nor parenchymal metas-tases were identified. She underwent an exploratory laparot-omy 13 days after computed tomography scan was per-formed and was found to have a 20�20�18-cm centralpelvic mass that was densely adherent to the sacrum, pelvic

side walls bilaterally, sigmoid colon, ureters, bladder, andvaginal apex. She also has multiple nodules on the smallbowel, large bowel, and omentum, ranging from 1 to 10 cmin diameter.

All visible disease was resected (Fig. 1), and the patho-logic assessment was high-grade malignant solitary fibroustumor. The tumor demonstrated more than 15–20 mitosesper 10 hpf and evidence of vascular invasion and perivas-cular necrosis. Immunostains were positive for CD34,CD10, focally AE1/AE3, Ki67, and were negative for calre-tinin, inhibin, smooth muscle actin, desmin, S-100,HMB45, CD117, estrogen receptors, progesterone recep-tors, CD361, and epithelial membrane antigen.

She received both chemotherapy and radiation in a“sandwiched” fashion, with three cycles of carboplatin atarea under the curve of six and paclitaxel 175 mg/m2 every3 weeks, followed by radiation to her pelvis up to 4,500cGy in 26 fraction and three additional cycles of carbopla-tin and paclitaxel. She remained overtly disease-free for 13months before presenting with fatigue, weakness, and mildright pelvic pain. Despite a normal physical examination, acomputed tomography scan demonstrated multiple mesen-teric implants and at least six lesions with diameter rangefrom 0.9 to 3.1 cm, consistent with recurrent disease.

The patient again was treated with complete surgicalextirpation, followed by six cycles of adjuvant carboplatinand paclitaxel-based chemotherapy based on tumor sensi-

Table 1. Summary of Female Genital Tract Solitary Fibrous Tumors

Summary ofFemale GenitalTract SolitaryFibrous Tumors

Age(y) Site

Size(mm) Symptoms Necrosis

Mitoses/10 hpf CD34 bcl-2 Margin Treatment Adjuvant Status

Vallat-Decouvelaereet al,10 1998

33 Parovarian 150 Yes Absent 5 � No data � Resection No Disease-free8 y

Recurrent No data No Yes 17 � No data No data Resection No data No dataHasegawa et al,13

199932 Paravagina 120 Yes No data No data � � � Resection No NED 7 y

Vadmal et al,9 2000 66 Vagina 10 No Absent Absent � � � Resection No NED 12 moFukunaga et al,4

200070 Vulva 150 No Yes 0.5 � � � Resection No NED 9 of

12 moWakami et al,11

200578 Uterus 240 Yes Yes Absent � � � Resection No NED 24 mo

Berzal-Cantalejo etal,14 2005

32 Fallopiantube

60 Yes Absent Absent � No data � Resection No No data

Chu et al,3 2006 78 Uterus 100 Yes Absent Absent � � � TAH BSO No NED 12 moIyengar,5 2007 52 Vagina 15 Yes Absent Absent � � � Excision No Recurrent at

10 moLocal 10 No Absent Absent � � � Excision No Recurrent at

29 moLocal 10 No Absent Absent � � � Excision No data No data

Biedrzycki et al,2

200745 Vulva 60 No Absent Absent � � � Resection No NED 3 of

12 moZubor et al,12 2007 50 Board

ligament140 Yes No 0.2 � � � TAH BSO No NED 6 y

Sidebotham et al,8

200915 Cervix 17 Yes Absent 3 � � � Trachelectomy No No data

Rahimi et al,7 2010 68 Cervix 17 No (HSIL) Absent Absent � � � Radicaltrachelectomy

No No data

hpf, high-power field; NED, no evidence of disease; TAH BSO, total abdominal hysterectomy and bilateral salpingo-oophorectomy;HSIL, high�grade squamous intraepithelial lesions.

VOL. 118, NO. 2, PART 2, AUGUST 2011 Sueblinvong et al Solitary Fibrous Tumors in the Pelvis 471

tivity assay. Again, she experienced a 12-month disease-free interval before routine computed tomography evalua-tion demonstrated multiple recurrent mesenteric soft tissuemasses. She declined additional surgical interventionand currently is being treated palliatively with carbopla-tin and paclitaxel. She received three cycles of carbopla-tin and taxol, with evidence of progressive disease oninterval computed tomography scan. She underwentexploratory laparotomy and tumor debulking again inSeptember 2010. Operative findings still revealed multi-ple nodules with diameter range from 2 to 5 cm overmesenteries, small bowel, and remnant of omentum. Shehad extensive tumor debulking with a cavitational ultra-sonic surgical aspirator (Cavitron Surgical Systems, Stam-ford CT) but microscopic tumor remained. Pathology re-vealed recurrent solitary fibrous tumor and c-kit stain-negative results. She continues on post-operative treatmentwith bevacizumab.

CASE 2

The patient is a 73-year-old woman who presented initiallyto her urogynecologist with symptoms of urinary retention.She has previously undergone hysterectomy and left salpin-go-oophorectomy for benign indications. Her physical ex-amination revealed an otherwise asymptomatic soft pelvicmass intruding into the vagina from the right lateral wall butextending superiorly into the pelvis. She underwent explor-atory laparotomy and excision of the mass. The intraoper-ative frozen section suggested a stromal compared withgranulosa cell tumor, and the patient underwent rightsalpingo-oophorectomy and surgical staging. The final pa-thology revealed solitary fibrous tumor with negative sur-gical margins. Immunostains demonstrated the tumor wasCD34-positive and bcl2-positive. There was no evidence oflymphovascular space involvement, necrosis, and mitosis.Based on the pathology, she elected follow-up without

adjuvant treatment and remains without evidence of dis-ease 21 months after surgery.

CASE 3

The patient is a 48-year-old woman referred after a com-puted tomography-guided biopsy of a pelvic mass demon-strated a low-grade spindle cell neoplasm suspicious forsolitary fibrous tumor. Her mass had been identified inci-dentally during an annual pelvic examination and under-went biopsy after serial ultrasound scans failed to demon-strated spontaneous regression. Exploratory laparotomyrevealed a solid mass emanating from right side of thepelvic floor and separate from the gynecologic structures.She underwent resection of the tumor as well as hysterec-tomy and bilateral salpingo-oophorectomy. Frozen sectiondemonstrated benign spindle cell neoplasm.

Immunoassessment of the fixed tissue was positive forCD34 and bcl-2 and negative for desmin, smooth muscleactin, and mitotic spindle-associated antigen, and the diag-nosis of solitary fibrous tumor was rendered. The mitoticactivity is less than 4 mitoses per 10 hpf and there was nonecrosis. The margins of the resection were negative fortumor. She elected follow-up without adjuvant treatmentand remains without evidence of disease 7 months aftersurgery.

COMMENTSolitary fibrous tumor is rare in the female genitaltract and pelvis. The median age for diagnosis ofsolitary fibrous tumor in our review was 56 years, butthis tumor has been found in all age groups (range5–87 years), with distribution equally betweensexes.1,15 By most assessments, approximately 30% ofsolitary fibrous tumors arise in extrathoracic loca-tions.16 To date, there are no data about risk factorsassociated with acquisition of extrathoracic solitaryfibrous tumor and there are limited data on treatmentand prognosis.

More than 80% of extrathoracic solitary fibroustumors present with a palpable mass or with localsymptoms resulting from compression of adjacentstructures attributable to an enlarging mass.17 Bycomparison, only 23% of thoracic solitary fibroustumors presented with symptoms, with the majoritybeing diagnosed incidentally on chest radiography orcomputed tomography scan. Abdominal and pelviclesions have ranged in size from 1.8 to 26 cm (mean7.9 cm), with some authors suggesting that size largerthan 10 cm is associated with a higher risk of metas-tasis.17 Approximately 4% of cases have been re-ported to present with paraneoplastic syndromes,hypoglycemia attributable to tumor secretion of insu-lin-like growth factor (Doege-Potter syndrome),18 orwith hypertrophic pulmonary osteoarthropathy.15

Fig. 1. Gross pathology from omental metastasis of high-grade malignant fibrous solitary tumor.Sueblinvong. Solitary Fibrous Tumors in the Pelvis. ObstetGynecol 2011.

472 Sueblinvong et al Solitary Fibrous Tumors in the Pelvis OBSTETRICS & GYNECOLOGY

Microscopically, this tumor is characterized bybland spindle cells with dense hyalinized collagenbundles, usually in a “patternless” arrangement andwith variable hypercellular and hypocellular areas.The tumor may have noticeable but varying degreesof vascularity, and focal areas of blood vessels with astag horn branching pattern characteristic of heman-giopericytomas are often found12 (Fig. 2). Accordingto the criteria of England et al,1 benign solitary fibroustumors are usually characterized by large areas ofcollagen production, low mitotic count generallyranging from 0 to 1 mitosis per 10 hpf, and with noabnormal mitoses. Benign tumors also are usuallysurrounded by a pseudocapsule. On the contrary,malignant tumors usually demonstrate high cellular-ity, infiltrative margins, hemorrhage or necrosis, andincreased mitotic activity (more than 4 mitoses per 10hpf) with or without atypical mitoses (Box 1). Immu-nohistochemically, solitary fibrous tumor typicallystain positive for CD34, bcl-2, and CD99, and stainnegative for �-smooth muscle actin, desmin, pan-cytokeratin, and S-100 protein16,19 (Fig. 3). Focal ex-pressions of estrogen-positive and progesterone re-ceptors also have been described in solitary fibroustumors and are postulated as possible therapeutictargets.19

The differential diagnosis of this condition includessmooth muscle tumors, monophasic malignant meso-thelioma, synovial sarcoma, fibrous histiocytoma, malig-nant peripheral nerve sheath tumor, fibrosarcoma, spin-dle cell carcinoma, gastrointestinal stromal tumor,fibromatosis, and reactive fibroinflammatory lesions.Fortunately, most of these neoplasms are reliably CD34-negative. Hemangiopericytoma, which may expressCD34, can be difficult to distinguish from solitary fi-brous tumor but is generally more cellular and morpho-logically homogeneous than solitary fibrous tumor.19

Complete resection with a clear surgical margin isusually curative of solitary fibrous tumor, even whenfeatures of malignancy are present. Local recurrenceor metastasis, usually to bone, lung, or liver, is thoughtto occur in 10%–15% of solitary fibrous tumor but hasbeen described in up to one-third of tumors inprevious reports.10 Lymph node metastasis is lesscommon, reported in only 6 of 223 cases (3%).1,20

Most authors report offering adjuvant treatmentto patients with malignant histologic features, incom-plete resection, or recurrent disease. Multiple chemo-therapy regimens have been described using doxoru-bicin, ifosfamide, paclitaxel, and cisplatin, all withmodest response rates.16,17 Immunohistochemicalsimilarities between solitary fibrous tumors and sub-

Fig. 2. Hematoxylin and eosin stain of high-grade malignantfibrous solitary tumor. A. Spindle cell with dense hyalinizedcollagen. B. Mitosis (arrows demonstrate samples of mito-sis). C. Tumor necrosis (arrow demonstrates necrosis area).D. Increased cellularity and pleomorphism.Sueblinvong. Solitary Fibrous Tumors in the Pelvis. ObstetGynecol 2011.

Fig. 3. Special stain from high-grade malignant fibroussolitary tumor. A. The CD34 stain is positive. B. The bcl-2stain is positive.Sueblinvong. Solitary Fibrous Tumors in the Pelvis. ObstetGynecol 2011.

Box 1. Summary of the High-Risk Factors forMalignancy

Increase cellularlityPleomorphismSize larger than 10 cmNecrosis or hemorrhageMitotic level more than 4 of 10 high-power fieldsPositive surgical margin

VOL. 118, NO. 2, PART 2, AUGUST 2011 Sueblinvong et al Solitary Fibrous Tumors in the Pelvis 473

mesothelial fibroblast21 have caused some authors toadvocate protocols similar to those used for soft tissuesarcomas, including gemcitabine, epirubicin, dacar-bazine, and liposomal doxorubicin, although datademonstrating efficacy are lacking. Radiation, al-though reported infrequently, has been associatedwith disease stabilization, as was seen in our patient.16

New strategies have been developed for treat-ment of this rare tumor, including targeted therapy totyrosine kinase inhibitor22 and intraperitoneal hyper-thermic chemotherapy.23 Stacchiotti et al23 describeexploiting the time-dependent shift of the dominantreceptor tyrosine kinase from the platelet-derivedgrowth factor receptor pathway to the insulin-likegrowth factor I receptor pathway from tissue beforeand after treatment with sumatinib malate in a seriesof patients with malignant solitary fibrous tumors,suggesting that these relatively low-toxicity ap-proaches merit a clinical trial.

Most of the patients with solitary fibrous tumorwill have excellent outcome with complete resectionof this tumor. Adjuvant treatment for high-risk pa-tients seems prudent, but the optimal strategy remainsto be determined. Both pathologic and clinical find-ings may be useful in gauging risk and assessing themerits of individualized adjuvant therapy. Long-termfollow-up of these patients is mandatory because laterecurrences are well-documented in our and otherseries.

REFERENCES1. England DM, Hochholzer L, McCarthy MJ. Localized benign

and malignant fibrous tumors of the pleura. A clinicopatho-logic review of 223 cases. Am J Surg Pathol 1989;13:640–58.

2. Biedrzycki OJ, Singh N, Habeeb H, Wathen N, Faruqi A.Solitary fibrous tumor of the female genital tract a case reportand review of the literature. Int J Gynecol Pathol 2007;26:259–64.

3. Chu PW, Liu JY, Peng YJ, Yu MH. Solitary fibrous tumor ofthe uterus. Taiwan J Obstet Gynecol 2006;45:350–2.

4. Fukunaga M. Atypical solitary fibrous tumor of the vulva. IntJ Gynecol Pathol 2000;19:164–8.

5. Iyengar P, Ismiil ND, Gerber D, Khalifa MA. Vaginal solitaryfibrous tumor: a case report with recurrence after incompleteexcision. J Low Genit Tract Dis 2007;11:50–4.

6. Nielsen GP, O’Connell JX, Dickersin GR, Rosenberg AE.Solitary fibrous tumor of soft tissue: a report of 15 cases,including 5 malignant examples with light microscopic, immu-nohistochemical, and ultrastructural data. Mod Pathol 1997;10:1028–37.

7. Rahimi K, Shaw PA, Chetty R. Solitary fibrous tumor of theuterine cervix. Int J Gynecol Pathol 2010;29:189–92.

8. Sidebotham EL, DeLair D, Comerci JT, Kayton ML, Abu-Rustum NR. Pediatric radical abdominal trachelectomy forsolitary fibrous tumor of the uterine cervix. Gynecol Oncol2009;115:302–5.

9. Vadmal MS, Pellegrini AE. Solitary fibrous tumor of thevagina. Am J Dermatopathol 2000;22:83–6.

10. Vallat-Decouvelaere AV, Dry SM, Fletcher CD. Atypical andmalignant solitary fibrous tumors in extrathoracic locations:evidence of their comparability to intra-thoracic tumors. Am JSurg Pathol 1998;22:1501–11.

11. Wakami K, Tateyama H, Kawashima H, Matsuno T, KamiyaY, Jin-No Y, et al. Solitary fibrous tumor of the uterusproducing high-molecular-weight insulin-like growth factor IIand associated with hypoglycemia. Int J Gynecol Pathol 2005;24:79–84.

12. Zubor P, Kajo K, Szunyogh N, Galo S, Danko J. A solitaryfibrous tumor in the broad ligament of the uterus. Pathol ResPract 2007;203:555–60.

13. Hasegawa T, Matsuno Y, Shimoda T, Hasegawa F, Sano T,Hirohashi S. Extrathoracic solitary fibrous tumors: their histo-logical variability and potentially aggressive behavior. HumPathol 1999;30:1464–73.

14. Berzal-Cantalejo F, Montesinos-Carbonell M, Montesinos-Carbonell ML, Calabuig-Crespo C, Martorell-Cebollada MA.Solitary fibrous tumor arising in the fallopian tube. GynecolOncol 2005;96:880–2.

15. Briselli M, Mark EJ, Dickersin GR. Solitary fibrous tumors ofthe pleura: eight new cases and review of 360 cases in theliterature. Cancer 1981;47:2678–89.

16. Kawamura S, Nakamura T, Oya T, Ishizawa S, Sakai Y,Tanaka T, et al. Advanced malignant solitary fibrous tumor inpelvis responding to radiation therapy. Pathol Int 2007;57:213–8.

17. Gold JS, Antonescu CR, Hajdu C, Ferrone CR, Hussain M,Lewis JJ, et al. Clinicopathologic correlates of solitary fibroustumors. Cancer 2002;94:1057–68.

18. Roy TM, Burns MV, Overly DJ, Curd BT. Solitary fibroustumor of the pleura with hypoglycemia: the Doege-Pottersyndrome. J Ky Med Assoc 1992;90:557–60.

19. Huang HY, Sung MT, Eng HL, Lee TY, Ko SF, Wang CC, etal. Solitary fibrous tumor of the abdominal wall: a report oftwo cases immunohistochemical, flow cytometric, and ultra-structural studies and literature review. APMIS 2002;110:253– 62.

20. Ito H, Fukuda M, Imamura Y, Fuse H. A malignant solitaryfibrous tumor in the retroperitoneum. Int J Clin Oncol 2008;13:173–5.

21. Hanau CA, Miettinen M. Solitary fibrous tumor: histologicaland immunohistochemical spectrum of benign and malignantvariants presenting at different sites. Hum Pathol 1995;26:440–9.

22. Stacchiotti S, Negri T, Palassini E, Conca E, Gronchi A,Morosi C, et al. Sunitinib malate and figitumumab in solitaryfibrous tumor: patterns and molecular bases of tumor response.Mol Cancer Ther 2010;9:1286–97.

23. Peixoto Callejo I. Peritoneal solitary fibrous tumour (solitaryfibrous tumor): long-term survival of recurrent and metasta-sised solitary fibrous tumor treated with cytoreductive surgeryand intraperitoneal chemotherapy. Clin Transl Oncol 2009;11:250–2.

474 Sueblinvong et al Solitary Fibrous Tumors in the Pelvis OBSTETRICS & GYNECOLOGY