—  SHORT COURSE #22  —

Tumors In The Liver - Diagnostic Problems

Case 5 - Metastatic Renal Cell Carcinoma

Linda D. Ferrell, M.D.
Wendy L. Frankel, M.D.


Clinical history:
53 year old man who was found to have a 3 cm mass in his liver on an abdominal CT scan.


Case 5 - Figure 1 - Clear cell carcinoma (arrow) metastatic to the liver, low power
Case 5 - Figure 2 - Clear cell carcinoma, high power
Case 5 - Figure 3 - EMA positivity, hight power


Pathologic findings:
The mass appeared yellow and hemorrhagic. The surrounding liver was normal. Sections show tumor composed of cells with clear cytoplasm.

Diagnosis: Metastatic Renal Cell Carcinoma

Comment
In most cases, the clinical history will be the most helpful feature in distinguishing tumors. H&E useful features seen more commonly with HCC include cirrhotic liver or chronic hepatitis. Features seen more frequently with metastatic lesions include multiple masses in a non-cirrhotic liver.

Special stains
  1. Mucin: Most HCC are negative but combined HCC-cholangiocarcinomas can be positive.

  2. Reticulin: Helpful in distinguishing benign from malignant hepatocellular tumors.
Immunoperoxidase stains
  1. Alpha-fetoprotein (AFP): AFP is a reasonably specific marker for hepatocellular carcinoma; however, the staining tends to be patchy and completely absent in more than half of the HCCs, and particularly has been noted to be absent in small, well-differentiated HCCs. AFP is useful when positive for HCC.

  2. Polyclonal CEA: pCEA highlights the bile canaliculi, and is relatively specific for hepatocellular differentiation, but only tends to stain the well to moderately-differentiated HCC's. This stain will also delineate outer cellular membranes in adenocarcinomas, which can potentially mimic a canalicular pattern on tangential sectioning.. The interpretation of pCEA is hindered by confusion in determining staining pattern in some cases – luminal with pseudoglandular HCC, membranous vs canalicular in some adenocarcinomas.

  3. Other adenocarcinoma markers (MOC-31, Ber-Epi-4, Leu-M1, etc): Negative in most HCC and positive in most adenocarcinomas

  4. Cytokeratins: Hepatocytes express the low molecular weight cytokeratins including 8 and 18, CAM5.2; while most adenocarcinomas express both low and high molecular weight cytokeratins. Cytokeratin AE1/3 is positive in adenocarcinomas and negative in many HCC. CAM5.2 cannot be used in isolation since cytokeratin CAM5.2 and AE1/3 will stain most adenocarcinomas. Cytokeratin 7 is negative in most HCC, but will focally stain smaller ductular-like hepatocytes or some acinar structures within HCC in our experience. Cytokeratin 7 is positive in many adenocarcinomas. Cytokeratin 20 is negative in HCC and positive some adenocarcinomas primarily colorectal. Cholangiocarcinoma are Cytokerain 7+ and Cytokeratin 20+ or – and so are similar to many metastatic adenocarcinomas. Cytokeratin stains are useful for site of origin in some cases of metastatic adenocarcinoma

  5. HepPar1, Hepatocyte: A newer hepatocyte antibody (Hep Par 1) is relatively specific for hepatocellular differentiation and only rarely stains adenocarcinomas. This antibody stains in a granular pattern within the cytoplasm to a varying degree within tumors with hepatocytic differentiation, but as with the polyclonal CEA, tends to be less sensitive for the poorly differentiated HCCs. Hepatoid adenocarcinomas reported positive

  6. CD10: Pattern of staining is similar to pCEA in HCC and negative in most adenocarcinomas. Advantage over pCEA – less confusion with determining pattern; disadvantage over pCEA – less sensitive .

  7. CD34: CD34 typically stains the endothelial-lined trabeculae in HCC and highlights the increased vascularity.

  8. ER/PR: Most HCC are negative. Be careful with determining site of origin of tumor. Up to 20% of adenocarcinomas can be positive and some metastatic breast carcinomas are negative.

  9. Her2-Neu: HCC are negative, while some adenocarcinomas are positive.


Differential between other tumors and HCC:

Distinction from adenocarcinoma. Monoclonal CEA is often diffusely positive in some types of adenocarcinomas, and usually does not stain hepatocellular tumors. Polyclonal CEA stains adenocarcinomas (membranous and cytoplasmic) in a different pattern from HCC (canalicular). Leu-M1, MOC31, B-72.3, and Lex tend to be positive in adenocarcinomas and negative HCC and when used in combination with CEA and perhaps the hepatocyte antibody (see above) can be helpful to distinguish poorly differentiated adenocarcinomas from HCC. Routine histochemical stains for the epithelial mucins such as mucicarmine or periodic acid-Schiff with digestion (PASD) are often helpful as mucins should not be present in HCC except in combined HCC-cholangiocarcinoma and in some cases of fibrolamellar variant of HCC (FLHCC). One must take some care in the interpretation of the PASD stain, however, since this method also reacts with many cytoplasmic glycoproteins produced by hepatocytes, resulting in a possible false positive interpretation. A combination of CK7, 19, and 20 profiles can be helpful as these tend to be positive in cholangiocarcinoma (CK19 is essentially always positive in cholangiocarcinoma) or metastatic carcinoma and negative in hepatocellular carcinoma.

Suggested panel for HCC vs adenocarcinoma (metastatic or cholangiocarcinoma):
Hepatocyte, pCEA, MOC-31. In our experience, this panel correctly classified 99% of tumors.

Add to help determine site of origin if necessary:
Cytokeratin 7 and 20.

Distinction from neuroendocrine tumors. HCC can also be difficult to distinguish from a neuroendrocrine neoplasm as both can form acinar or trabecular-like structures, and can be composed of relatively large tumor cells with abundant eosinophilic cytoplasm and round nuclei. Features that favor a neuroendocrine tumor in such cases are a prominent vascular or capillary network, and/or stromal hyalinization. These neuroendocrine tumors can rarely arise as a primary lesion in the liver, but otherwise, are almost always metastatic. Focal neuroendocrine differentiation has been noted in HCC, including the fibrolamellar variant, as well as in hepatoblastoma, using various markers such as neuron specific enolase (NSE), protein gene product 9.5 (PGP 9.5), vasoactive intestinal peptide (VIP), calcitonin, and S-100 but diffuse staining with a marker such as chromogranin or synaptophysin would strongly support a neuroendocrine tumor.

Distinction from other tumor types. Clear cell carcinomas in the liver can pose a diagnostic challenge to distinguish the clear cell variant of HCC from clear cell renal cell carcinoma metastatic to the liver. In a cirrhotic liver, the diagnosis of clear cell variant of HCC can be made with enough certainty that stains would not be necessary. However, for lesions in a noncirrhotic liver without significant AFP elevation, the likelihood of a metastatic lesion makes differentiation more critical. Keratin profiles are not helpful as both of these tumors typically show similar staining (positive for CAM5.2, negative for CK7 and 20). However, HCC of these clear cell types will often demonstrate polyclonal CEA canalicular staining, while renal cell carcinomas show no canalicular pattern. Other useful markers are EMA, which tends to be positive in RCC and negative in HCC, and the hepatocyte antibody (see above) that does not stain RCC.

Melanomas can also mimic HCCs, but S-100 and HMB-45 are usually, but not always, negative in hepatocellular tumors. Rarely, an adrenal cortical tumor may need to be distinguished from a primary hepatocellular tumor. In these instances, positive staining for inhibin A, which has a high percentage of positivity in adrenal tumors but not in hepatacytic lesions may be helpful in addition to the hepatocyte markers previously discussed such as polyclonal CEA and hepatocyte antibody. The use of immunohistochemistry in the differentiation of HCC from primary mesenchymal tumors will be discussed below.

References
  1. Borscheri N, Roessner A, Rocken C. Canalicular imunostaining of neprilysin (CD10) as a diagnostic marker for hepatocellular carcinoma. Am J Surg Pathol 25:1297-1303, 2001.

  2. Chu PG, Ishizawa S, Wu E, Weiss LM. Hepatocyte antigen as a marker of hepatocellular carcinoma. Am J Surg Pathol 26:978-988, 2002.

  3. Chu P, Wu E, Weiss L: Cytokeratin 7 and cytokeratin 20 expression in epithelial neoplasms: a survey of 435 cases. Mod Pathol 13:962-972, 2000.

  4. Fan Z, van de Rijn M, Montgomery K, Rouse RV. Hep par 1 antibody stain for the differential diagnosis of hepatocellular carcinoma: 676 tumors tested using tissue microarrays and conventional tissue sections. Mod Pathol 16:137-44, 2003.

  5. Fucich L, Cheles M, Thung S, et al: Primary versus metastatic hepatic carcinoma: An immunohistochemical study of 34 cases. Arch Pathol and Lab Med 118:927-930, 1994.

  6. Goodman Z, Ishak K, Langloss J, et al: Combined hepatocellular-cholangiocarcinoma: A histologic and immunohistochemical study. Cancer 55:124-135, 1985.

  7. Karkar S, Muir T, Murphy LM, Lloyd RV, Burgart LJ. Immunoreactivity of Hep Par 1 in hepatic and extrahepatic tumors and its correlation with albumin in situ hybridization in hepatocellular carcinoma. Am J Clin Pathol 119:361-6, 2003.

  8. Maeda T, Kajiyama K, Adachi E, et al: The expression of cytokeratins 7, 19, 20 in primary and metastatic carcinomas of the liver. Mod Pathol 9:901-909, 1996.

  9. Maitra A, Murkata LA, Albores-Saavedra J. Immunoreactivity for hepatcyte parafffin 1 antibody in adenocarcinoms of the gastrointestinal tract. Am J Clin Pathol 115:689-94, 2001.

  10. Minervini M, Demetris A, Lee R, et al: Utilization of hepatocyte-specific antibody in the immunocytochemical evaluation of liver tumors. Mod Pathol 10:686-692, 1997.

  11. Morrison C, Marsh W, Frankel WL. A comparison of CD10 to pCEA, MOC-31 and hepatocyte for the distinction of malignant tumors in the liver, Mod Pathol 15:1279-1289, 2002.

  12. Murakata L, Ishak K, Nzeako U: Clear cell carcinoma of the liver: A comparative immunohistochemical study with renal clear cell carcinoma. Mod Pathol 13:874-881, 2000.

  13. Porcell AI, DeYoung BR, Proca DM, Frankel WL. Immunohistochemical analysis of hepatocellular and adenocarcinoma in the liver: MOC31 compares favorably with other putative markers. Mod Pathol 13:773-778, 2000.

  14. Renshaw A, Granter S: A comparison of A103 and inhibin reactivity in adrenal cortical tumors: distinction from hepatocellular carcinoma and renal tumors. Mod Pathol 11:1160-1164, 1998.

  15. Rullier A, Le Bail B, Fawaz R, et al: Cytokeratin 7 and 20 expression in cholangiocarcinomas varies along the biliary tract but still differs from that in colorectal carcinoma metastases. Am J Surg Pathol 24:870-876, 2000.

  16. Wang J, Dhillon A, Sankey E, et al: Neuroendocrine differentiation in primary neoplasms of the liver. Journal of Pathology 163:61-67, 1991.

  17. Wang N, Zee S, Zarbo R, et al: Coordinate expression of cytokeratins 7 and 20 defines unique subsets of carcinomas. Applied Immunohistochemistry 3:99-107, 1995.


 HCC Adenocarcinoma RCC NET
AFP +/- -* - -
Hepatocye + -* - -
pCEA + (canalicular) +
(cytoplasmic/membranous) 		- -
LMWCk (8,18) + + +
Ck7 - +- - -
Ck20 - -+ - -
CD10 +/- (canalicular) -** +
MOC31 - + - -
Chromogranin - - - +
EMA +
Vimentin - - +

* Positive in hepatoid variant, ** Rarely positive in the cytoplasm