Liver & intrahepatic bile ducts
Hepatocellular carcinoma
Sarcomatoid variant
Editorial Board Member: Raul S. Gonzalez, M.D.
Editor-in-Chief: Debra L. Zynger, M.D.
Topic Completed: 9 May 2019
Minor changes: 24 September 2020
Copyright: 2002-2021, PathologyOutlines.com, Inc.
PubMed Search: Sarcomatoid hepatocellular carcinoma[TIAB]
Table of Contents
Definition / general | Essential features | Terminology | ICD coding | Epidemiology | Clinical features | Prognostic factors | Case reports | Treatment | Gross description | Gross images | Microscopic (histologic) description | Microscopic (histologic) images | Positive stains | Negative stains | Molecular / cytogenetics description | Sample pathology report | Differential diagnosis | Board review style question #1 | Board review style answer #1 | Board review style question #2 | Board review style answer #2Cite this page: Fels Elliott DR, Gill RM. Sarcomatoid variant. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/livertumorsarcomatoid.html. Accessed January 18th, 2021.
Definition / general
- Hepatocellular carcinoma (HCC) variant partially or entirely composed of malignant spindle cells with or without heterologous differentiation
Essential features
- Tumor partially or entirely composed of malignant spindle cells
- May have extensive necrosis and heterologous elements
- Older, predominantly male patients
- Worse prognosis than classic HCC
- Sarcomatoid transformation has been associated with repeated chemotherapy / chemoembolization
Terminology
- Also called spindle cell HCC, pseudosarcomatous HCC
ICD coding
- ICD-10: C22.7 - Other specified carcinomas of liver
Epidemiology
- Incidence ranges from 1.8 - 3.9% of all HCC in small case series (Cancer 1987;59:310, Cancer 1996;77:51)
- Patients tend to be older and predominantly male (Hepatology 2019;69:209)
- Sarcomatoid change is more frequent in patients undergoing repeated chemotherapy or transarterial chemoembolization (Cancer Chemother Pharmacol 1989;23:S4)
Clinical features
- Higher incidence of extrahepatic disease (e.g. lymph nodes, lungs, bone) and lower serum alpha fetoprotein (AFP) in comparison to classic HCC (Surg Pathol Clin 2013;6:367)
Prognostic factors
- Worse prognosis compared to classic HCC (Surg Pathol Clin 2013;6:367, Hepatology 2019;69:209, Int J Surg 2018;55:145, Ann Surg Oncol 2015;22:S1048)
- 3 year survival < 20% (Int J Surg 2018;55:145, Ann Surg Oncol 2015;22:S1048, Hepatology 2019;69:209)
- Prognostic factors for HCC: stage (TNM), single lesion versus multifocal, size, vascular invasion, portal vein thrombosis, severity of underlying liver disease (Liver Int 2009;29:502, J Surg Oncol 2018;117:644)
Case reports
- 62 year old man with a history of hepatitis B (J Cancer Res Ther 2015;11:665)
- 68 year old woman with abdominal distension (World J Surg Oncol 2017;15:219)
- 68 year old man with a right liver mass (Diagn Pathol 2015;10:40)
Treatment
- Surgical resection
- Radiofrequency ablation
- Transarterial chemoembolization (TACE)
- Transplantation (e.g. Milan criteria, modified by some institutions, Nat Rev Gastroenterol Hepatol 2017;14:203)
Gross description
- Poorly circumscribed, lobulated mass; may contain areas of necrosis and possibly heterologous elements
Gross images
Images hosted on other servers:
Well defined pink yellow mass
Whiteish tumor
Microscopic (histologic) description
- Partially or entirely composed of malignant spindle cells
- Component of classic HCC is often present to help confirm the diagnosis
- Various types of heterologous elements have been reported, including rhabdoid, osteoid and chondroid differentiation; may have pleomorphic and osteoclast-like giant cells (Virchows Arch 1999;434:511, Am J Surg Pathol 2007;31:817, Pathol Int 2000;50:919, Clin Mol Hepatol 2014;20:313, Diagn Pathol 2015;10:40)
Microscopic (histologic) images
Contributed by Ryan M. Gill, M.D., Ph.D.
Variable cellularity
Malignant spindle cells
Mitotic figures
Cytokeratin MNF
HepPar1
Mixed sarcomatoid HCC and cholangiocarcinoma
Sarcomatoid area
Mitotic figures
Arginase
Positive stains
- Cytokeratin variably positive (20 - 60%) (Cancer 1987;59:310, Cancer 1996;77:51)
Negative stains
- Hepatocellular markers (HepPar1, arginase1, glypican 3) typically negative in the sarcomatoid component
Molecular / cytogenetics description
- Negative albumin mRNA by ISH in the sarcomatoid component (Pathol Res Pract 2013;209:249)
Sample pathology report
- Liver, mass, core biopsy:
- Hepatocellular carcinoma, sarcomatoid variant (see comment)
- Comment: This tumor shows two distinct morphologies. One component shows features of classic hepatocellular carcinoma, while the second component shows sarcomatoid features including pleomorphic spindle cells. Cytokeratin is variably positive and hepatocellular markers (HepPar1, arginase1 and glypican 3) are negative in the sarcomatoid component, as is typical for this variant.
Differential diagnosis
- Sarcoma: undifferentiated pleomorphic sarcoma and fibrosarcoma
- Clinical history of sarcoma
- Will not have area of classic HCC
- Immunohistochemistry (entirely negative for pancytokeratin) and potentially molecular testing (e.g. next generation sequencing cancer gene panel) are necessary for diagnosis
- Metastatic sarcomatoid carcinoma:
- Will not have area of classic HCC
- Clinical history of carcinoma
- Usually multiple nodules
- Immunohistochemistry (pancytokeratin+) and potentially molecular testing (e.g. next generation sequencing cancer gene panel) are necessary for diagnosis
- Negative for hepatocellular markers, positive keratin staining (usually patchy, perhaps only for high molecular weight keratins, e.g. as detected on MNF116)
Board review style question #1
Which of the following histologic features is characteristic of this variant of hepatocellular carcinoma?
- Cytokeratin is always negative in the sarcomatoid component
- Hepatocellular markers are usually positive in the sarcomatoid component
- May show rhabdoid, chondroid or osteoid differentiation
- Must be entirely composed of malignant spindle cells
- Necrosis is not a common feature
Board review style answer #1
C. May show rhabdoid, chondroid or osteoid differentiation
Reference: Sarcomatoid hepatocellular carcinoma
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Reference: Sarcomatoid hepatocellular carcinoma
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Board review style question #2
Which of the following is true regarding the sarcomatoid variant of hepatocellular carcinoma (HCC)?
- Associated with a better prognosis than classic HCC
- Higher serum AFP in comparison to classic HCC
- More common in patients undergoing repeated chemotherapy or transarterial chemoembolization
- Patients are predominantly female
- There is a lower incidence of extrahepatic spread in comparison to classic HCC
Board review style answer #2
C. More common in patients undergoing repeated chemotherapy or transarterial chemoembolization
Reference: Sarcomatoid hepatocellular carcinoma
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Reference: Sarcomatoid hepatocellular carcinoma
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