Böbreğin soliter fibröz tümörü: bir olgu sunumu ve literatürün detaylı gözden geçirilmesi

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Introduction
Solitary fibrous tumor (SFT) is a rare spindle cell neoplasm. It frequently arises from the serosal surface
especially in pleural cavity (1). Extrapleural SFTs are
very rare, and to our knowledge, there are only 28
cases of SFTs located in kidney. Clinically, this neoplasm can mimic renal malignancies. They are mostly
benign lesions and characteristically exhibit diffuse
CD34 positivity. We herein report an additional case
of SFT originating from renal sinus and filling the renal pelvis, and summarize the clinical and pathological features of 29 previously reported SFT cases of
the kidney.
Case Report
A 49-year-old woman presented with a 3-month
history of right flank pain, without gross hematuria.
Physical examination was unremarkable. Computed
tomography scan of the abdomen showed that a
6x6x5 cm, contrast-enhanced mass was localized on
the right renal pelvis (Figure 1a). Radical nephrectomy was performed subsequently. Specimen consisted of right kidney covered by perinephric adipose
tissue. Macroscopic examination showed a well-circumscribed unencapsulated 6x6x5 cm mass originating from renal sinus and growing into the renal pelvis. The tumor had a firm, gray to white cut surface.
Macroscopically, no necrosis, cyst formation, hemorrhage or renal vascular invasions were noted (Figure
1b). Microscopically, tumor was composed of hypercellular nodular areas and among them less cellular
areas containing dense collagenous bands (Figures
2a, 2b). Neoplastic cells had small ovoid to spindle
shaped nuclei with indistinct cytoplasm. Tumor cells
were interspersed by a stroma including thin walled
vascular spaces. There were no mitotic figures, necrosis or atypia.
Immunohistochemically, tumor cells were diffusely
positive for vimentin and CD34 (Figure 3). Bcl-2 was
* Department of Pathology, Gulhane Military Medical Faculty
** Department of Urology, Gulhane Military Medical Faculty
*** Department of Radiodiagnostic Radiology, Gulhane Military Medical Faculty
This case was presented as poster presentation at the 17th National
Pathology Congress (September 8-13, 2007), Istanbul, Turkey
Reprint request: Dr. Bülent Kurt, Department of Pathology, Gulhane Military
Medical Faculty, Etlik-06018, Ankara, Turkey
E-mail: bkurt_md@yahoo.com
Date submitted: February 12, 2008 • Date accepted: April 25, 2008Volume 51 • Issue 2 Solitary fi brous tumor of the kidney • 117
weakly positive. Ki-67 (MIB-I) proliferation index was
approximately 1%. Smooth muscle actin (SMA), desmin, S-100 protein, CD117 and CD99 were negative.
It was diagnosed as SFT with the histological and immunohistochemical findings.
Discussion
Solitary fibrous tumor has first been described in
1931 (2). Etiology is unknown. Immunohistochemical
and ultrastructural studies favor that the cell of origin
for SFT is fibroblastic/primitive mesenchymal cells
(3). They are most commonly described as pleural lesions, but many extrapleural locations have also been
reported (1,4-7). A review about renal SFT has been recently published, which includes 19 cases. But, to our
knowledge there are 29 cases in the literature (Table I)
(8-31). First renal SFT has been reported by Gelb at al.
in 1996 (8). Almost all renal SFTs are seen in adult life
with a wide range (18-85) of age. Only one pediatric
case has been reported in a 4-year-old boy (Case 26).
Tumor predominantly affects female (F/M: 17/12).
The most frequent clinical findings are abdominal
Figure 1. A. Enhanced mass localized on right renal pelvis, B. Well-circumscribed unencapsulated mass
Figure 3. Strong CD34 positivity (x100)
Figure 2. A. Hypercellular and hypocellular areas (HEx50), B. Less cellular dense collagenous bands containing areas (HEx100)118 • June 2009 • Gulhane Med J Kurt et al.
or flank pain. Occasionally abdominal/flank mass or
hematuria can be seen. Some of tumors are detected
incidentally. There is no predilection for left or right
kidney. Only one case was bilateral (Case 17). Tumor
was localized in various parts of kidney including parenchyma (13 cases), renal sinus (5 cases) and renal
capsule (8 cases) (Table I).
Macroscopically, renal SFTs are classically well circumscribed, firm, solid and frequently lobular with
gray to white cut surface. Myxoid, hemorrhagic and
necrotic changes are occasionally observed. The tumor had a wide range of size (2-25 cm). Most of the
cases were well circumscribed without cystic, hemorrhagic or necrotic changes. Only three cases had necrotic areas and two of them had infiltrating borders.
One of these cases was diagnosed as malignant SFT
(Case 24).
Microscopically, benign SFTs consist of hypocellular and hypercellular areas. Tumors are composed
of spindle cells without an obvious growth pattern,
so called “patternless pattern”. SFTs are tumors with
variable cellularity and composed of a mixture of
haphazard, storiform, short fascicular arrangements
of bland spindle cells and collagenous bands. Spindle
cells are not atypical and have little cytoplasm with
indistinct borders. They are highly vascular tumors,
and hemangiopericytoma like pattern can be seen in
some areas. Myxoid changes and fibrosis may be obTable I. Clinical features of the previously reported solitary fibrous tumors of the kidney
No and References Age/sex Presentation Location in kidney Borders Follow-up
1 Gelb et al. 1996 (8) 48/F Flank mass and hematuria Right, renal capsule Well C.* **
2 Fain et al. 1996 (11) 45/F Upper abdominal pain Right, intraparenchymal Well C. 8 months
3 Fain et al. 1996 (11) 46/F Abdominal pain Right, intraparenchymal Well C. 33 months
4 Fain et al. 1996 (11) 51/M Chest pain Left, intraparenchymal Well C. 2 months
5 Hasegawa et al. 1996 (12) 64/M Hematuria Intraparenchymal Well C. 8 months
6 Fukunaga et al. 1997 (13) 33/F Lower abdominal pain Right, renal peripelvis Well C. No capsule 90 months
7 Fukunaga et al. 1997 (13) 36/F Lower abdominal pain Left, renal peripelvis Well C. No capsule 1 year
8 Leroy et al. 2000 (15) 66/F Abdominal pain, hematuria Right, intraparenchymal Renal invasion 9 months
9 Morimitsu et al. 2000 (14) 72/F Not specified U Well C. 10 months
10 Wang et al. 2001 (16) 41/M Hematuria Left, intraparenchymal Well C. encapsulated 48 months
11 Wang et al. 2001 (16) 72/M Abdominal pain Right, parenchymal Well C No capsule 5 months
12 Yazaki et al. 2001 (17) 70/M Not specified Right, renal pelvis Well C. 60 months
13 Kohl et al. 2006 (18) 85/F Flank pain Left, renal sinus Well C. U
14 Cortez-Gutierrez et al. 2001 (19) 28/F Abdominal pain Left, renal capsule Well C. 12 months
15 Magro et al. 2002 (20) 31/F Flank pain Right, intraparenchymal Well C. 8 month
16 Durand et al. 2003 (21) 35/M U Renal sinus Well. C No capsule U
17 Ibarguren et al. 2003 (22) 51/F Abdominal mass Bilateral NE NE
18 Bugel et al. 2003 (23) 60/F NE Right, intraparenchymal NE NE
19 Yamada et al. 2004 (24) 59/M Not specified Left, renal capsule Well C. encapsulated 48 months
20 Gres et al. 2004 (25) 83/M U Right U U
21 Johnson et al. 2005 (26) 51/F Back pain Right, renal capsule Well C. U
22 Yamaguchi et al. 2005 (10) 51/F Lower back pain Left, renal capsule Well C. U
23 Koroku et al. 2006 (27) 18/F Abdominal pain Left, renal sinus NE 15 months
24 Fine SM et al. 2006 (9) 76/M Not specified Left, intraparenchymal Infiltrative U
25 Alvarez et al. 2006 (28) 36/M Flank colic pain Right, renal capsule NE NE
26 Ferrari et al. 2006 (29) 4/M Nonproductive cough Right, intraparenchymal Well C. U
27 Bozkurt et al. 2007 (30) 51/F Flank pain, hematuria Left, parenchymal Well C. 10 months
28 Znati et al. 2007 (31) 70/M Back pain, hematuria Left, parenchyma and perirenal tissue Focal infiltrative 6 months
29 Current case 49/F Flank pain Right, renal sinus Well C. 1 month
*: Well C: Well-circumscribed, **: Died after surgery, U: Unknown, NE: Not reported in the English literatureVolume 51 • Issue 2 Solitary fi brous tumor of the kidney • 119
served. Occasionally mast cells and lymphocytes can
be seen. Mitosis is usually scarce (less than 3 per 10
high-power fields). Although most of SFTs are histologically benign, there are malignant SFTs reported
in the literature (9). Malignant SFTs are highly cellular lesions. They show necrosis, focally or moderately nuclear atypia, numerous mitoses (more than 4
mitosis per 10 HPF) and/or infiltrative margins (10).
We were able to find histological features for 22 of 29
renal SFTs in the literature (Table II). Almost all of the
cases were benign with typical histopathological features for SFT. Only one renal SFT case had malignant
features. Mitosis was rare (less than 3 mitosis per HPF)
in benign renal SFTs. Malign SFT had high grade sarcomatous areas (more than 90% of tumor) composed
of hyperchromatic and pleomorphic spindled cells
surrounding staghorn like blood vessels with frequent mitosis and foci of tumor necrosis (9). This tumor
also contained typical SFT areas. Focally aggregated
mature fat cells were reported in one case of benign
SFT (32).
Immunohistochemically, diffuse vimentin and
CD34 positivity are seen in almost all of SFTs. CD34
and CD99 positivity are 90-95% and 70% in SFT, respectively (32). Furthermore, Flint and Van de Rijn
have shown CD34 positivity in 77% and %78.5 of SFT
cases, respectively in their studies (33,34). Bcl-2 expression in SFTs is found in various degrees (20-35%)
Table II. Pathologic features of the previously reported solitary fibrous tumors of the kidney
No and References Size (cm) Cyst Hemorrhage Necrosis Mitosis CD34 Vimentin Bcl-2 CD99 SMA Desmin
1 Gelb et al. 1996 (8) 3 - - - Rare + U U U - -
2 Fain et al. 1996 (11) 6 - - - Rare U + U U - -
3 Fain et al. 1996 (11) 7.2 - - - Rare + + U U - -
4 Fain et al. 1996 (11) 4.5 - - - Rare + + U U - -
5 Hasegawa et al. 1996 (12) 4.5 - - - Rare + + + U - -
6 Fukunaga et al. 1997 (13) 3.5 - - - Rare + + U U - -
7 Fukunaga et al. 1997 (13) 2 - - - Rare + + U U - -
8 Leroy et al. 2000 (15) 9 - - - Rare + + U Focal - -
9 Morimitsu et al. 2000 (14) 8 - - - Absent + U U U U U
10 Wang et al. 2001 (16) 14 - - - Rare + + + U - -
11 Wang et al. 2001 (16) 13 - - - Rare + + + U - -
12 Yazaki et al. 2001 (17) 6 - - - Absent + + U U - U
13 Kohl et al. 2006 (18) 3.5 - - - Absent + + + U - -
14 Cortez-Gutierrez et al. 2001 (19) 15 - - - Absent + + U U - -
15 Magro et al. 2002 (20) 8.6 - - - Rare + + Focal Focal - -
16 Durand et al. 2003 (21) 17 NE NE NE Rare + + U U U U
17 Ibarguren et al. 2003 (22) L-25, R-2 NE NE NE Absent + + + U - -
18 Bugel et al. 2003 (23) 11 NE NE NE NE + + NE NE NE +
19 Yamada et al. 2004 (24 6.5 - - - Absent + + + + - -
20 Gres et al. 2004 (25) 9 U U U U + U + + U U
21 Johnson et al. 2005 (26) 11 - - - Rare Focal + + Focal - -
22 Yamaguchi et al. 2005 (10) 10 - - - Absent + + + + - U
23 Koroku et al. 2006 (27) 3 NE NE NE NE + NE NE NE NE NE
24 Fine SM et al. 2006 (9) 12 - - + Frequent + U Focal - - U
25 Alvarez et al. 2006 (28 ) 10 NE NE NE NE + + U + - -
26 Ferrari et al. 2006 (29) 15 U U U U U U U U U U
27 Bozkurt et al. 2007 (30) 3.7 - - - Absent + + + + - -
28 Znati et al. 2007 (31) 15 + - + Absent + + + + - U
29 Current case 6 - - - Absent + + Focal - - -
U: Unknown, NE: Not reported in the English literature120 • June 2009 • Gulhane Med J Kurt et al.
in different studies (14,32). In a small group of SFTs
(20-35%), SMA expression was also reported (32). S-
100 protein, desmin and cytokeratin positivity were
occasionally reported. There are no well-documented data for immunohistochemical staining pattern
of renal SFTs. Almost all of renal SFTs (26/27) were
diffusely positive for CD34. Only one case showed
focal CD34 positivity (Case 21). Vimentin was diffusely positive in all cases (23/23). Nine cases exhibited
CD99 positivity (Diffuse in 6 cases, focal in 3 cases).
Two cases were negative for CD99. Bcl-2 was diffusely positive in most of the cases (11/14). Focal Bcl-2
expression was also shown in remaining cases (3/14).
Neither SMA nor desmin expression was present in
renal SFTs.
SFTs need to be distinguished from benign and malignant spindle cell tumors of the kidney. Differential
diagnosis should include hemangiopericytoma
(HPCs), fibroma, angiomyolipoma, leiomyoma/leiomyosarcoma, schwannoma, neurofibroma, perineurioma, monophasic synovial sarcoma and sarcomatoid renal cell carcinoma. Less than 30 primary renal
HPC have been published in the literature. Most of
them arise from the renal sinus and perirenal tissue.
Distinction from hemangiopericytoma is sometimes
difficult because the histological and immunohistochemical features of these two entities may show overlaps. Macroscopically hemorrhage is more common
in HPC than in SFT. Although SFTs may consist hemangiopericytoma-like areas, presence of numerous,
variably ectatic or compressed, thin-walled branching
vessels having a staghorn configuration are more
frequently seen in hemangiopericytoma (2). In HPC,
neoplastic cells are usually diffusely dispersed and
stromal hyalinization and varying cellularity are not
usual in contrast to SFT (32). Immunohistochemically,
most HPCs express CD34 but usually lesser degree
than SFTs (2). So, there may be cases that can not
be distinguished from each other. Our case showed
diffuse and strong CD34 positivity (Figure 3). Renal
medullary fibromas are usually smaller than 1 cm in
diameter with parenchymal localization. They are negative for CD34. Lack of muscle and adipose tissue
components distinguish SFT from angiomyolipoma.
But sometimes SFTs may include adipose component.
Leiomyomas/leiomyosarcomas show high percentage of SMA/desmin positivity and not express CD34.
Schwannomas, neurofibromas and perineuriomas
may occur in kidney. Schwannomas and neurofibromas express S-100 protein. Fifty percent of perineuriomas may show CD34 positivity but in contrast to SFT
they exhibit also consistent EMA immunoreactivity.
Sarcomatoid renal cell carcinomas show immunoreactivity with cytokeratins without CD34 expression.
The monophasic synovial sarcoma may demonstrate some difficulties in the differential diagnosis. In
contrast to SFTs, monophasic synovial sarcoma show
at least focal immunoreactivity with cytokeratin and
lack of CD34 expression.
Prognosis is generally good for SFTs. Most of them
are non-recurring and non-metastazing tumors.
Roughly 10-15% of SFTs are malignant (2). Only one
case of previously reported 28 renal SFT has been reported as malignant (9), but unfortunately follow-up
information was not available for this case. No recurrence or metastasis have been noted for the 19 cases
with available follow-up (3-90 months).
In conclusion, we summarized clinical and pathological features of 29 cases of renal SFT. These tumors
may mimic malignant tumors, clinically and radiographically. But most of renal SFTs are benign and their
prognosis is very good. Only one case of malignant SFT
of kidney has been reported. In differential diagnosis,
the most useful tool is diffuse CD34 positivity to distinguish it from other spindle cell tumors of the kidney.