International Journal of Urology (2006) 13, 1000–1002
Blackwell Publishing AsiaMelbourne, AustraliaIJUInternational Journal of Urology0919-81722006 Blackwell Publishing Asia Pty LtdJuly 200613710001002Case Report Renal malignant fibrous histiocytoma
Correspondence: Shrawan K Singh MS MCh, Professor of
Urology, Postgraduate Institute of Medical Education and
Research, #202-A, Sector 24-A, Chandigarh, PIN - 160 023,
Received 4 May 2005; accepted 7 November 2005.
Primary renal inflammatory malignant fibrous histiocytoma: A
SHRAWAN K SINGH,1 ARUP K MANDAL,1 MAYANK MOHAN AGARWAL1 AND ASHIM DAS2
Departments of 1Urology and 2Histopathology, Postgraduate Institute of Medical Education and Research,
Abstract Renal inflammatory malignant fibrous histiocytoma (MFH) is an extremely rare lesion and is a great masquerader of
common benign renal inflammatory lesions, especially xanthogranulomatous pyelonephritis (XGPN). The clinical presentation of
mass with fever and peripheral leucocytosis (marked at times), and marked inflammatory, predominantly neutrophilic, infiltrate
obscuring the malignant cells on histopathology, can lead to delay in the diagnosis of this poor prognostic malignant tumor. We
present the case of a patient who underwent radical nephrectomy with a clinical diagnosis of renal malignancy, but histopathology
showing XGPN. The patient showed an initial clinical response, only to recur two times, ultimately leading to a histological and
immunohistochemical diagnosis of inflammatory MFH. The diagnosis, histology, therapeutic options and prognosis of this rare
lesion are discussed.
Key words fibrous, histiocytoma, leukemoid reaction, malignant, renal neoplasms.
Malignant Fibrous Histiocytoma (MFH) is the most com-
mon subtype of soft-tissue sarcoma in adults.1 The most
common location is the extremities (67–75%) followed by
the retroperitoneum (6–16%).2 However, primary MFH of
the kidney is extremely rare. Both clinical and histopatho-
logical diagnoses of MFH, especially of the inflammatory
variety, are extremely difficult. We report an exemplary
case of primary renal MFH (inflammatory) and discuss the
diagnosis, histology, therapeutic options and prognosis of
this rare lesion.
A 58-year-old man presented with left-flank pain and fever
of 2 months duration. Clinical examination revealed left
renal mass, which on contrast enhanced computed tomog-
raphy (CECT) and magnetic resonance imaging was char-
acterized as 10 × 12 cm left renal superior polar mass with
central necrosis (Fig. 1). The contralateral kidney was nor-
mal. Peripheral leucocytosis with total leukocyte count
(TLC) 29 000/µL (normal range: 4000–11 000/µL) and
raised erythrocyte sedimentation rate of 65 mm in the first
hour (normal range 0–10) were noted. Renal functions
were normal. Metastatic workup was negative. He under-
went left radical nephrectomy by thoracoabdominal
approach. Histopathology revealed xanthogranulomatous
pyelonephritis with no evidence of malignancy. He
improved clinically, but 3 months later he presented with
left chest pain, fever and cough. Investigations revealed left
lower zone loculated empyema thoracis (CECT) and leu-
kemoid reaction (TLC, 32 000/mL). Failing an attempt
of percutaneous drainage, he underwent open drainage
with pleurectomy. Histopathology suggested non-specific
inflammation. Resolution of leukemoid reaction was
accompanied by clinical improvement. Again 2 months
later, he presented with left-flank pain, low appetite and
weight loss. CECT revealed three heterodense and hetero-
geneously enhancing masses, one each in the left posterior
thoracic cavity (10 × 10 cm), lesser sac (6 × 6 cm, overly-
ing aorta & inferior vena cava) and left renal fossa
(8 × 8 cm) (Fig. 2). Marked leukemoid reaction with TLC,
70 000–105 000/mL (polymorphonuclear leukocytes, 90–
98% raised leukocyte alkaline phosphatase score) was
also noted. Fine needle aspiration cytology of the mass
was non-contributory. Cultures for bacteria, tuberculosis
and fungus were negative. Tests for immunocompetence,
including neutrophil function (nitroblue tetrazolium),
Mantoux skin sensitivity test (for delayed hypersensitivity)
and serum immunoglobulins A, M, G, D and E were nor-
mal. On exploratory thoracolaparotomy, the tumors were
found to be non-resectable, so biopsies only were taken.
Histopathology of these biopsy specimens, and the review
of previous slides, showed the presence of an intense neu-
trophilic infiltrate, with scattered spindle cells and foam
cells (some showing atypia), and fine vascular network
(Fig. 3a,b). Immunohistochemistry of both present and
previous specimens revealed CD68-positive xanthoma
cells. The tumor also stained positive for CD34, but
Renal malignant fibrous histiocytoma 1001
negative for cytokeratin. A diagnosis of inflammatory
MFH was made. The patient’s health rapidly deteriorated
and he succumbed to the disease within 1 month.
Renal infiltration by retroperitoneal MFH is known.3 How-
ever, primary renal MFH is an extremely rare lesion and
only four cases of an inflammatory variety have been
reported so far in the published literature.2,4,5 MFH is renal
capsular in origin and occurs most commonly in the 5th−
7th decade with equal sex distribution and left renal
predilection.6 There are four histological subtypes of MFH:
storiform-pleomorphic, giant-cell, myxoid and inflamma-
tory.1 Common presenting features are flank pain, fever,
weight loss, palpable mass and, rarely, hematuria.7 It cannot
be differentiated clinically and radiologically from other
common renal mass lesions.6,7 Definite diagnosis (espe-
cially for the inflammatory variety) is difficult by histopa-
thology, whereas immunohistochemistry is capable of
making a definite diagnosis.1,7
The most typical form, storiform-pleomorphic variety,
consists of highly pleomorphic tumor cells with storiform
growth pattern mixed with pleomorphic inflammatory
infiltrate. The inflammatory variety is characterized by
benign and malignant xanthoma cells, spindle cells and an
intense inflammatory infiltrate rich in neutrophils that may
obscure the often bland looking neoplastic cells.1,8 The
presence of delicate vasculature gives an appearance of
granulation tissue.1 It may also be associated with periph-
eral leukemoid reaction.8 Therefore, it masquerades as
upper pole of left kidney.
Magnetic resonance imaging showing mass lesion in
recurrence in left lower thorax.
Contrast enhanced CT scan showing heterogenous
cal section (H&E) demonstrate neutrophilic infiltrate, pleo-
morphic xanthoma cells and spindle cells.
Low (a) and high (b) power views of histopathologi-
1002SK Singh et al.
benign inflammatory lesions (e.g. reactive inflammatory
pseudotumors, malakoplakia and xanthogranulomatous
pyelonephritis),1,3,9 as happened in our case. These tumors
stain positive for CD34, CD68 and vimentin, and negative
for cytokeratin and leukocyte-lineage markers.1
Initial treatment of MFH in all cases has been radical
nephrectomy because of suspected renal cell carcinoma.6,7
Despite radical ablation, the tumor shows a very strong
predilection for local recurrence often associated with dis-
tant metastasis. Local recurrence occurred in most of the
reported cases, ranging 3–24 months after surgery. Sixty
percent of patients died of the disease, mostly within
12 months of surgery.4,6 Chemotherapy has been tried in
few patients and has shown only slight apparent survival
advantage (disease-free up to 10–28 months follow up).
Ifosphamide, cisplatin, vinca alkaloids, mitomycin-C, adri-
amycin, cyclophosphamide and dacarbazine have been
used in various combinations.2,6,10 Adjuvant radiotherapy
has not been found to be of obvious benefit.4,6 Definitive
assessment of response to adjuvant therapy, both chemo-
therapy and radiotherapy, is not possible because of the
extreme rarity of the tumor. Our patient was unsuitable for
any kind of adjuvant therapy because of poor performance
status and died within 1 month of diagnosis (total 7 months
from initial presentation).
In conclusion, awareness of this entity and a high index
of suspicion both by the clinician and the pathologist are
required to establish an early diagnosis and institute early
systemic therapy. Currently, this is the only hope for
improving survival of patients affected by this rare and
highly aggressive lesion.
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