|Year : 2015 | Volume
| Issue : 2 | Page : 157-159
Primary leiomyosarcoma of kidney: A rare case report
Pooja Srivastava, Rajni Prasad, Geetika Khanna
Department of Pathology, Vardhman Mahavir Medical College and Safdarjung Hospital (VMMC-SJH), New Delhi, India
|Date of Web Publication||13-Jul-2015|
Dr. Pooja Srivastava
270 Hauz Rani Malviya Nagar, New Delhi - 110 017
Source of Support: None, Conflict of Interest: None
Primary leiomyosarcoma of kidney is extremely rare tumour accounting for 0.12% of renal tumours. Radiological investigations are not able to differentiate between leiomyosarcoma and sarcomatoid renal cell carcinoma. Histopathological examination along with aid of immunohistochemistry is required to make a definitive diagnosis. We present a rare case of primary renal leiomyosarcoma occurring in a 50 years old female.
Keywords: Primary leiomyosarcoma kidney, sarcoma, sarcomatoid carcinoma
|How to cite this article:|
Srivastava P, Prasad R, Khanna G. Primary leiomyosarcoma of kidney: A rare case report. Muller J Med Sci Res 2015;6:157-9
| Introduction|| |
Primary sarcomas constitute 0.8% to 2.7% of all renal tumours in adults.  Leiomyosarcoma, fibrosarcoma and liposarcoma are the most frequent malignant renal neoplasm of pure mesenchymal origin out of which leiomyosarcoma is the most common type  constituting 0.12% of all invasive renal malignancies.  The symptoms and signs are generally similar to those of renal cell carcinoma, like pain, palpable mass and hematuria. Radiological findings are also non-specific and diagnosis is generally made post operatively. The histogenesis of renal leiomyosarcoma is unclear. As the prognosis of this tumour is markedly different from that of renal cell carcinoma, it is important to consider the diagnosis in all cases of renal mass with unusual gross and histopathological features.
| Case Report|| |
50 year old female presented with dull aching pain in left hypochondrium since three years. No associated complaints were found. Previous medical history comprised of hypertension since two years. Physical examination revealed a mass in left hypochondrium extending to the left lumbar region. Ultrasound imaging revealed a mass lesion of size 7.2 × 6.4 × 5.1 cm having internal vascularity in left kidney. It was involving renal pelvis, upper and middle pole and calyceal system. Contrast enhanced computed tomography revealed large left renal mass infiltrating the perinephric fat and involving gerota's fascia. Lymph nodes were enlarged in left para aortic region. The patient underwent left radical nephrectomy. Intraoperatively left kidney with intact gerota's fascia was excised along with multiple enlarged lymph nodes and was sent for histopathological examination. Grossly the kidney was enlarged measuring 12 × 8 × 6 cm in size. The outer surface was smooth bosselated and congested with adherent capsule. Cut- section revealed a well circumscribed, lobulated greyish white firm mass measuring 10 × 5 × 6 cm in the upper pole reaching up to the capsule and displacing the pelvis. It had a characteristic whorled appearance. Microscopically, the tumour composed predominantly of spindle cells, arranged in bundles, interlacing fascicles and whorls [Figure 1]. The tumour cells had moderate, eosinophilic cytoplasm and oval vesicular nuclei showing moderate pleomorphism. Mitotic figures were 4-5/10 hpf. No epithelial area was recognized even after extensive sampling of the tumour. Sections from renal pelvis and ureter were unremarkable. Masson's trichrome stain helped to confirm smooth muscle origin. On immunohistochemistry the tumour cells were diffusely positive for smooth muscle actin (SMA) [Figure 2], focally positive for desmin and negative for cytokeratin (CK), S-100, HMB-45 and RCC antigen. Hence a final diagnosis of renal leiomyosarcoma was established. The patient was closely followed for one year but thereafter was lost to follow-up.
|Figure 1: Microphotograph showing spindle cells having pleomorphic nuclei with blunt ends and eosinophilic cytoplasm arranged in interlacing fascicles [H&E 400×]|
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|Figure 2: Microphotograph showing tumour cells diffusely positive for SMA [IHC 400×]|
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| Discussion|| |
Leiomyosarcoma of kidney was first described by Berry in 1919  but till date they have been reported as case reports or as components of larger series of renal sarcomas in the literature. Leiomyosarcoma accounts for 0.5%-1.5% of all the malignancies arising in the adult kidney.  A female predominance has been noted, with women being twice more common than men and majority of patients presenting in the 4 th through 6 th decade of life.  There are only two relatively larger studies of renal leiomyosarcoma, one comprising 10 cases by Deyrup et al.  and the other of 27 cases by Miller et al.  Both these studies involved cases collected from three large institutions over a period of 21 and 23 years respectively. Miller et al.  studied only H&E sections without using immunohistochemistry. Hence in fact there is only one case series by Deyrup et al., where there was a complete analysis of cases.  Histogenesis remains obscure, as renal sarcomas may arise from the smooth muscle fibres of the renal parenchyma, capsule, renal pelvis or vessels.
Leiomyosarcoma usually present with flank pain, hematuria and an abdominal mass, thus mimicking renal cell carcinoma. Radiographic findings are non-specific and diagnosis is usually made postoperatively. Histologically, leiomyosarcoma has to be differentiated from sarcomatoid renal cell carcinoma, leiomyoma and angiomyolipoma.  Leiomyosarcoma can be differentiated from leiomyoma by presence of mitosis and necrosis in malignant tumour, although cellular pleomorphism can be seen in both. Renal angiomyolipoma shows fascicles of smooth muscle cells admixed with mature fat and thick walled blood vessels. Sarcomatoid carcinomas are composed predominantly of pleomorphic cells and lack the characteristic alternating fascicles and cytological features of smooth muscle cells. Leiomyosarcoma on the other hand has monomorphic nuclei, although some cases may demonstrate pleomorphism. Diagnosis of sarcomatoid renal cell carcinoma can be made if typical renal cell carcinoma is seen somewhere in the tumour. So, a thorough sampling of the tumour is required to rule out any epithelial component of sarcomatoid renal cell carcinoma, which forms the closest differential diagnosis of renal leiomyosarcoma. Grigon et al.  in their study suggested that to make a diagnosis of primary renal sarcoma the following criteria should be met:
- The patient must not have or have had a sarcoma elsewhere to rule out metastasis,
- Gross must be compatible with origin in the kidney rather than involvement due to retroperitoneal sarcoma
- Sarcomatoid renal cell carcinoma must be excluded.
Immunohistochemically the tumour cells of leiomyosarcoma are positive for desmin, SMA, calponin, h-caldesmon and negative for antibodies to CK, S-100 and HMB-45. The angiomyolipoma will show HMB-45 positivity while the sarcomatoid variant of renal cell carcinoma will be CK positive.
Small size (<5 cm), low histologic grade and renal limited disease are associated with most favourable outcome.  Histologic grade of the tumour is assigned based on mitotic count, necrosis and nuclear pleomorphism.  Renal leiomyosarcomas are aggressive tumours with a five year survival rate of 29%-36%; most patients dying within one year of diagnosis.  High grade sarcomas often metastasize, the lungs being the primary site of spread, and prognosis is poor.  The treatment of choice is radical nephrectomy but it may not be feasible due to the involvement of adjacent structures by the tumour. The most important prognostic factor is tumour free resected margin. Large size and metastasis to adjacent organs at the time of diagnosis makes the prognosis poor. Although radiotherapy and chemotherapy is considered as adjuvant treatment, these treatments do not appear to change the clinical course much. 
| References|| |
Dhawan S, Chopra P, Dhawan S. Primary renal leiomyosarcoma: A diagnostic challenge. Urol Ann 2012;4:48-50.
Aiken W, Gibson T, Williams S, Gaskin D. Leiomyosarcoma of the kidney. West Indian Med J 2009;58:183-4.
Dhamne SA, Gadgil NM, Padmanabhan A. Leiomyosarcoma of the renal pelvis. Indian J Pathol Microbiol 2009;52:549-51.
Deyrup AT, Montgomery E, Fisher C. Leiomyosarcoma of the kidney: A clinicopathologic study. Am J Surg Pathol 2004;28:178-82.
Miller JS, Zhou M, Brimo F, Guo CC, Epstein JI. Primary leiomyosarcoma of the kidney: A clinicopathologic study of 27 cases. Am J Surg Pathol 2010;34:238-42.
[Figure 1], [Figure 2]