|
|
| Line 3: |
Line 3: |
| {{CMG}}; {{AE}} {{SC}} | | {{CMG}}; {{AE}} {{SC}} |
| ==Overview== | | ==Overview== |
|
| |
|
| |
| ==Pathology==
| |
|
| |
| ===Histopathology===
| |
| Metanephric adenoma is diagnosed histologically. The tumours can be located at upper pole, lower pole and mid-hilar region of the kidney; they are well circumscribed but unencapsulated, tan pink, with possible cystic and hemorrhagic foci. They show a uniform architecture of closely packed acinar or tubular structures of mature and bland appearance with scanty interposed stroma.<ref name=pmid9390023>{{Cite journal | last1 = Kovacs | first1 = G. | last2 = Akhtar | first2 = M. | last3 = Beckwith | first3 = BJ. | last4 = Bugert | first4 = P. | last5 = Cooper | first5 = CS. | last6 = Delahunt | first6 = B. | last7 = Eble | first7 = JN. | last8 = Fleming | first8 = S. | last9 = Ljungberg | first9 = B. | last10 = Medeiros | first10 = L. Jeffrey | last11 = Moch | first11 = Holger | last12 = Reuter | first12 = Victor E. | last13 = Ritz | first13 = Eberhard | last14 = Roos | first14 = Göran | last15 = Schmidt | first15 = Dietmar | last16 = Srigley | first16 = John R. | last17 = Störkel | first17 = Stephan | last18 = Van Den Berg | first18 = Eva | last19 = Zbar | first19 = Bert | title = The Heidelberg classification of renal cell tumours | journal = J Pathol | volume = 183 | issue = 2 | pages = 131–3 |date=Oct 1997 | doi = 10.1002/(SICI)1096-9896(199710)183:2<131::AID-PATH931>3.0.CO;2-G | pmid = 9390023 | display-authors = 8 }}</ref><ref name=pmid1333853>{{Cite journal | last1 = Brisigotti | first1 = M. | last2 = Cozzutto | first2 = C. | last3 = Fabbretti | first3 = G. | last4 = Sergi | first4 = C. | last5 = Callea | first5 = F. | title = Metanephric adenoma | journal = Histol Histopathol | volume = 7 | issue = 4 | pages = 689–92 |date=Oct 1992 | doi = | pmid = 1333853 }}</ref><ref name=pmid7755148>{{Cite journal | last1 = Jones | first1 = E. C. | last2 = Pins | first2 = M. | last3 = Dickersin | first3 = G. R. | last4 = Young | first4 = R. H. | title = Metanephric adenoma of the kidney. A clinicopathological, immunohistochemical, flow cytometric, cytogenetic, and electron microscopic study of seven cases | journal = The American journal of surgical pathology | volume = 19 | issue = 6 | pages = 615–626 | year = 1995 | pmid = 7755148 | doi=10.1097/00000478-199506000-00001}}</ref><ref name=bostwick>Bostwick DG, Eble JN (2008) Urologic Surgical Pathology. St Louis, Mosby, p118.</ref><ref name=pmid9503505>{{Cite journal | last1 = Grignon | first1 = D. J. | last2 = Eble | first2 = J. N. | title = Papillary and metanephric adenomas of the kidney | journal = Seminars in diagnostic pathology | volume = 15 | issue = 1 | pages = 41–53 | year = 1998 | pmid = 9503505}}</ref> Cells are small with dark staining nuclei and inconspicuous nucleoli. Blastema is absent whereas calcospherites may be present. Glomeruloid figures are a striking finding, reminiscent of early fetal metenephric tissue. The lumen of the acini may contain otherwise epithelial infoldings or fibrillary material but it is quite often empty. Mitoses are conspicuously absent.<ref name=pmid9390023/><ref name=pmid1333853/><ref name=pmid7755148>{{Cite journal | last1 = Jones | first1 = E. C. | last2 = Pins | first2 = M. | last3 = Dickersin | first3 = G. R. | last4 = Young | first4 = R. H. | title = Metanephric adenoma of the kidney. A clinicopathological, immunohistochemical, flow cytometric, cytogenetic, and electron microscopic study of seven cases | journal = The American journal of surgical pathology | volume = 19 | issue = 6 | pages = 615–626 | year = 1995 | pmid = 7755148 | doi=10.1097/00000478-199506000-00001}}</ref><ref name=bostwick/><ref name=pmid9503505>{{Cite journal | last1 = Grignon | first1 = D. J. | last2 = Eble | first2 = J. N. | title = Papillary and metanephric adenomas of the kidney | journal = Seminars in diagnostic pathology | volume = 15 | issue = 1 | pages = 41–53 | year = 1998 | pmid = 9503505}}</ref>
| |
| In the series reported by Jones ''et al.'' tumour cells were reactive for Leu7 in 3 cases of 5, to vimentine in 4 of 6, to cytocheratin in 2 of 6, to epithelial membrane antigen in 1 of 6 cases and muscle specific antigen in 1 of 6.<ref>Jones EC, Pins M, Dickersin GR, Young RH (1995) Metanephric adenoma of the kidney. A clinicopathological, immunohistochemical, flow cytometry, cytogenetic and electron microscopic study of seven cases. Am J Surg Pathol 19(6):615-626.</ref>
| |
| Olgac ''et al.'' found that intense and diffuse immunoreactivity for alpha-methylacyl-CoA racemase (AMACR) is useful in differentiating renal cell carcinoma from MA but a panel including AMACR, CK7 and CD57 is better in this differential diagnosis.<ref>Olgac S, Hutchinson B, Tickoo SK, Reuter VE (2006) Alpha-methylacyl-CoA racemase as a marker in the differential diagnosis of metanephric adenoma. Mod Pathol 19:218-224.</ref>
| |
| Differential diagnosis may be quite difficult indeed as exemplified by the three malignancies initially diagnosed as MA that later metastasized, in the report by Pins et al.<ref>Pins MR, Jones EC, Martul EV, Kamat BR, Umlas J, Renshaw AA (1999) Metanephric adenoma-like tumours of the kidney. Report of three malignancies with emphasis on discriminating features. Arch Pathol Lab Med. 123:415-420.</ref>
| |
|
| |
| ===Cytogenetic characteristics===
| |
|
| |
| Brunelli ''et al.'' stated that genetic analysis of chromosome 7, 17, and Y may facilitate discrimination of MA from papillary renal cell carcinoma in difficult cases. Their study showed that MA lacks the frequent gain of chromosomes 7 and 17 and losses of the Y chromosome that are typical of papillary renal cell neoplasms, suggesting that MA is not related to renal cell carcinoma and papillary adenoma.<ref>Brunelli M, Eble JN, Zhang S, Martignoni G, Cheng L (2003) Metanephric adenoma lacks the gains of chromosomes 7 and 17 and loss of Y that are typical of papillary renal cell carcinoma and papillary adenoma. Mod Pathol 16(10):1060-1063.</ref>
| |
|
| |
|
| |
|
| ==Gross Pathology== | | ==Gross Pathology== |
| Characteristic findings of metanephric adenoma on gross pathology include: | | Characteristic findings of metanephric adenoma on gross pathology include:<ref>Metanephric adenoma. Libre Pathology 2015. http://librepathology.org/wiki/index.php/Metanephric_adenoma Accessed on November 9, 2015 </ref> |
| | | * Solitary [[mass]] |
| | * Sharply circumscribed |
| | * Not encapsulated |
|
| |
|
| ==Microscopic Pathology== | | ==Microscopic Pathology== |
| The characteristics of metanephric adenomas include: | | The characteristics of metanephric adenomas include: |
| | * Small uniform cells with: |
| | :* Fine chromatin |
| | :* No apparent nucleolus |
| | :* Smooth nuclear membrane |
| | * Variable architecture: |
| | :* May be sheets, ductal or micropapillary |
| | * Psammoma bodies may present |
|
| |
|
|
| |
|
![metanephric adenoma[2]](/index.php?title=Special:Upload&wpDestFile=Metanephric_adenoma_high_mag.jpg){kind=link}
