Figure 1
Abdominal ultrassonography.
Extraskeletal Osteosarcoma of the Kidney
SectionUroradiology & genital male imaging
Case TypeClinical Cases
AuthorsBarbosa, L; Basso, S; Raposo, J; Noruegas, MJ.
Connected authors
47 years, female
Clinical History
Woman, 47 years, abdominal pain of acute onset.
Imaging Findings
The patient was admitted with acute abdominal pain in the left hypochondrium. Chest X-ray [Fig. 1a] showed pleural effusion and abdominal X-ray [Fig, 1b] showed an abnormal opacity.
Laboratory tests revealed a slight increase in the protein-creatinine ratio (PCR >6).
Abdominal ultrassonography revealed slight hepatomegaly with homogeneous texture. In the left hypochondrium there was an expansive lesion with ill-defined boundaries, heterogeneous texture and gross calcifications.
The abdominal CT with i.v. contrast enhancement [Figs. 3a-g] revealed paramedian left abdominal bulky mass lesion with 20 x 16 x 12 cm, irregular and relatively well- defined borders, predominance of solid points, as well as amorphous calcifications.
This lesion was pushing the left kidney establishing no cleavage planes, supporting the hypothesis that the kidney would be the organ of origin.
Selective embolisation was performed and then surgical resection was performed.
The pathologic study revealed an extra-skeletal osteosarcoma of the kidney [Figs. 4a-e].
Unfortunately, the patient died shortly after surgery.
Laboratory tests revealed a slight increase in the protein-creatinine ratio (PCR >6).
Abdominal ultrassonography revealed slight hepatomegaly with homogeneous texture. In the left hypochondrium there was an expansive lesion with ill-defined boundaries, heterogeneous texture and gross calcifications.
The abdominal CT with i.v. contrast enhancement [Figs. 3a-g] revealed paramedian left abdominal bulky mass lesion with 20 x 16 x 12 cm, irregular and relatively well- defined borders, predominance of solid points, as well as amorphous calcifications.
This lesion was pushing the left kidney establishing no cleavage planes, supporting the hypothesis that the kidney would be the organ of origin.
Selective embolisation was performed and then surgical resection was performed.
The pathologic study revealed an extra-skeletal osteosarcoma of the kidney [Figs. 4a-e].
Unfortunately, the patient died shortly after surgery.
Discussion
Primary renal osteosarcoma is an extremely rare tumour. Its cell type of origin
is undifferentiated mesenchymal cells of the kidney. One of the typical characteristics
is extensive ossification in a “sunburst” pattern, sometimes viewable
in routine radiographs. However, one should consider other possible diagnoses, including the sarcomatoid variant of renal cell carcinoma and osteogenic sarcoma with metastasis to the kidney which may also contain ossification [2].
Radiographic differentiation of these three malignancies is difficult and, sometimes, only a pathologic study allows their differentiation.
The presence of renal tumour ossification makes the hypothesis of osteogenic sarcoma of the bone with kidney metastasis more likely than primary renal osteosarcoma because the first one is by far a more common malignancy.
Elevated alkaline phosphatase levels is a good method of differentiating between
primary renal osteosarcoma and metastatic osteogenic sarcoma of the kidney when a calcified renal tumour is found in the absence of a clinical history of a primary tumour.
Microscopically, the tumours contain varying amounts of neoplastic osteoid and bone, sometimes together with islands of malignant-appearing cartilage. Like osteosarcoma of bone, extraskeletal osteosarcoma show a striking variation in histological appearance and focally resembled malignant fibrous histiocytoma, fibrosarcoma, and malignant schwannoma. The prevailing sites of metastases are the lung, the regional lymph nodes and bone.
The prognosis is extremely poor (mean survival, 8-22 months) despite an aggressive therapeutic approach including radical nephrectomy, radiation and chemotherapy [3, 4]
is undifferentiated mesenchymal cells of the kidney. One of the typical characteristics
is extensive ossification in a “sunburst” pattern, sometimes viewable
in routine radiographs. However, one should consider other possible diagnoses, including the sarcomatoid variant of renal cell carcinoma and osteogenic sarcoma with metastasis to the kidney which may also contain ossification [2].
Radiographic differentiation of these three malignancies is difficult and, sometimes, only a pathologic study allows their differentiation.
The presence of renal tumour ossification makes the hypothesis of osteogenic sarcoma of the bone with kidney metastasis more likely than primary renal osteosarcoma because the first one is by far a more common malignancy.
Elevated alkaline phosphatase levels is a good method of differentiating between
primary renal osteosarcoma and metastatic osteogenic sarcoma of the kidney when a calcified renal tumour is found in the absence of a clinical history of a primary tumour.
Microscopically, the tumours contain varying amounts of neoplastic osteoid and bone, sometimes together with islands of malignant-appearing cartilage. Like osteosarcoma of bone, extraskeletal osteosarcoma show a striking variation in histological appearance and focally resembled malignant fibrous histiocytoma, fibrosarcoma, and malignant schwannoma. The prevailing sites of metastases are the lung, the regional lymph nodes and bone.
The prognosis is extremely poor (mean survival, 8-22 months) despite an aggressive therapeutic approach including radical nephrectomy, radiation and chemotherapy [3, 4]
Differential Diagnosis List
Extraskeletal Osteosarcoma of the Kidney
Sarcomatoid variant of renal cell carcinoma.
Osteogenic sarcoma with metastasis to the kidney.
Final Diagnosis
Extraskeletal Osteosarcoma of the Kidney
References
[1] Secil M, Mungan U, Yorukoglu K, Dicle O (2005) Retroperitoneal Extraskeletal Osteosarcoma. Radiology 237: 880-883 (PMID: 16304110)
[2] Venkata S. Katabathina, Raghunandan Vikram, Arpit M. Nagar, Pheroze Tamboli, Christine O. Menias, and Srinivasa R. Prasad (2010) Mesenchymal Neoplasms of the Kidney in Adults: Imaging Spectrum with Radiologic-Pathologic Correlation. Radiographics 30:1525-1540 (PMID: 18094306)
[3] Cioppa T, Marrelli D, Neri A, et al. (2007) Primary osteosarcoma of the kidney with retroperitoneal hemorrhage: case report and review of the literature. Tumori 93(2): 213-216 (PMID: 17557574)
[4] Zagoria RJ, Dyer RB. (1991) Computed tomography of primary renal osteosarcoma. J Comput Assist Tomogr 15(1):146-148 (PMID: 1987185)
Case information
| URL: | https://www.eurorad.org/case/9288 |
| DOI: | 10.1594/EURORAD/CASE.9288 |
| ISSN: | 1563-4086 |
Figure 2
Computed Tomography scan
Left abdominal bulky mass lesion, 20 x 16 x 12 cm, which has irregular and relatively well defined borders, central cystic component and amorphous calcifications in the posterior slope.
The mass has predominance of solid component that enhances after administration of intravenous contrast.
This lesion pushes above the left kidney, with which it doesn\'t establishes cleavage planes, which supports the hypothesis of the organ of origin.
The lower third of the left kidney the morphology is preserved.
Coronal reconstruction
Coronal reconstruction.
Sagital reconstruction
Figure 3
Pathology
amp = 400x
The histological examination shows a malignant neoplasia composed by fusiform and markedly atypical cells.
amp = 200x
The tumor has numerous areas with chondroblastic differentiation.
amp = 200x
There are sparse areas with osteoid formation.
amp = 400x
There are focal areas with rhabdomyioblastic differentiation.
amp = 100x
The observed neoplasia is here clearly separated from the renal parenchyma by fibrous tissue.
Computed Tomography scan
Left abdominal bulky mass lesion, 20 x 16 x 12 cm, which has irregular and relatively well defined borders, central cystic component and amorphous calcifications in the posterior slope.
The mass has predominance of solid component that enhances after administration of intravenous contrast.
This lesion pushes above the left kidney, with which it doesn\'t establishes cleavage planes, which supports the hypothesis of the organ of origin.
The lower third of the left kidney the morphology is preserved.
Coronal reconstruction
Coronal reconstruction.
Sagital reconstruction
Pathology
amp = 400x
The histological examination shows a malignant neoplasia composed by fusiform and markedly atypical cells.
amp = 200x
The tumor has numerous areas with chondroblastic differentiation.
amp = 200x
There are sparse areas with osteoid formation.
amp = 400x
There are focal areas with rhabdomyioblastic differentiation.
amp = 100x
The observed neoplasia is here clearly separated from the renal parenchyma by fibrous tissue.
