Conexiant
Login
  • The Analytical Scientist
  • The Cannabis Scientist
  • The Medicine Maker
  • The Ophthalmologist
  • The Pathologist
  • The Traditional Scientist
The Pathologist
  • Explore Pathology

    Explore

    • Latest
    • Insights
    • Case Studies
    • Opinion & Personal Narratives
    • Research & Innovations
    • Product Profiles

    Featured Topics

    • Molecular Pathology
    • Infectious Disease
    • Digital Pathology

    Issues

    • Latest Issue
    • Archive
  • Subspecialties
    • Oncology
    • Histology
    • Cytology
    • Hematology
    • Endocrinology
    • Neurology
    • Microbiology & Immunology
    • Forensics
    • Pathologists' Assistants
  • Training & Education

    Career Development

    • Professional Development
    • Career Pathways
    • Workforce Trends

    Educational Resources

    • Guidelines & Recommendations
    • App Notes

    Events

    • Webinars
    • Live Events
  • Events
    • Live Events
    • Webinars
  • Profiles & Community

    People & Profiles

    • Power List
    • Voices in the Community
    • Authors & Contributors
  • Multimedia
    • Video
    • Podcasts
Subscribe
Subscribe

False

The Pathologist / Issues / 2021 / Mar / Case of the Month (2)
Histology Histology Oncology Cytology

Case of the Month

03/24/2021 Quick Read (pre 2022) 1 min read

Share

A 58-year-old female presented with a right breast mass.

Which of the following immunohistochemical markers is the most specific for this entity?

a. β-catenin
b. p63
c. CK7
d. ER
e. CK20

Click here to register your guess.

We will reveal the answer next month.

Do you have an interesting case that you would like us to feature? Email it to edit@thepathologist.com.

Submitted by Emily R. McMullen, House Officer IV at the University of Michigan, Ann Arbor, Michigan, USA.

Answer to March's Case of the Month

C. Histiocytic sarcoma

Histiocytic sarcoma (HS) is a rare malignant neoplasm derived from histiocytes. It is most common in the sixth decade of life, with similar incidence among males and females. Histiocytic sarcoma most commonly occurs in extranodal locations such as soft tissue, skin, and gastrointestinal tract, but can also involve lymph nodes. Histologically, the malignant cells are usually large, reminiscent of histiocytes, with mild to severe pleomorphism. Varying numbers of inflammatory cells (small lymphocytes, histiocytes, plasma cells, and eosinophils) can be seen in the background. By immunohistochemistry, HS is usually positive for multiple histiocytic markers: CD4, CD11c, CD14, CD63, CD163, lysozyme, PU.1, and CD45. A subset of cases is S100-positive; another carries the BRAF V600E mutation.

Differential diagnosis includes hematopoietic tumors (large cell lymphomas of B and T cell lineage, classic Hodgkin lymphoma, myeloid sarcoma), dendritic cell neoplasms (follicular and interdigitating dendritic cell sarcoma), Langerhans cell sarcoma, Rosai-Dorfman disease, and non-hematopoietic neoplasms. Among these, carcinoma and melanoma with histiocytic features should be excluded. A variety of mesenchymal neoplasms is also in the differential diagnosis of HS, including inflammatory myeofibroblastic tumor, liposarcoma (inflammatory or dedifferentiated), myxoinflammatory fibroblastic sarcoma, histiocytic variant of angiosarcoma, and others. A large panel of immunostains is usually needed to resolve the differential diagnosis and make a diagnosis of HS.

Although Langerhans cell sarcoma can stain positive for S100, it typically stains for CD1a and langerin, which are not seen in histiocytic sarcoma. Interdigitating dendritic cell sarcoma also stains for S100, but the staining pattern is usually much stronger and diffuse than seen in histiocytic sarcoma. Furthermore, CD68 and CD163 staining in interdigitating dendritic cell sarcoma is generally only focal, if present at all.  Unlike histiocytic sarcoma, follicular dendritic cell sarcoma will typically stain for dendritic markers such as CD21, CD23, or CD35.

Histiocytic sarcoma is an aggressive tumor with no well-established management; however, most patients are treated with the CHOP (cyclophosphamide, daunorubicin, vincristine, and prednisone) chemotherapy protocol common in lymphoma treatment. Median survival for treated patients is approximately 2.5 years. A subset of cases shows PD-L1 expression, which could have therapeutic implications for future treatment. 

Submitted by Kyle D. Perry, Senior Pathologist,  Henry Ford Health System, Detroit, MI, USA.

Newsletters

Receive the latest pathology news, personalities, education, and career development – weekly to your inbox.

Newsletter Signup Image

References

  1. JL Hornick et al.,  Am J Surg Pathol, 28, 1133 (2004). PMID: 15316312.
  2. SH Swerdlow et al., WHO Classification of Tumours of Haematopoietic and Lymphoid Tissues, revised 4th edition. International Agency for Research on Cancer: 2017.
  3. F Facchetti et al.,  Virchows Arch, 471, 467 (2017). PMID: 28695297.
  4. JS Reis-Filho et al., WHO Classification of Tumours of the Breast, 4th edition. International Agency for Research on Cancer: 2012.
  5. N Cha et al., Am J Case Rep, 19, 203 (2018). PMID: 29472521.
  6. ER McMullen et al., Arch Pathol Lab Med, 143, 1492 (2019). PMID: 31765246.
  7. MM Koker, CG Kleer, Am J Surg Pathol, 28, 1506 (2004). PMID: 15489655.

Explore More in Pathology

Dive deeper into the world of pathology. Explore the latest articles, case studies, expert insights, and groundbreaking research.

False

Advertisement

Recommended

False

Related Content

Your Newest Colleague?
Histology
Your Newest Colleague?

January 6, 2022

1 min read

The need for AI-based end-to-end biomarkers in oncology

Biospecimen Access For Biotechs
Histology
Biospecimen Access For Biotechs

February 14, 2022

1 min read

Quality, provenance, and “taking pot luck”

Case of the Month
Histology
Case of the Month

February 21, 2022

1 min read

The Art of the Laboratory
Histology
The Art of the Laboratory

March 25, 2022

1 min read

For the seventh time, we asked you to share the images you think capture the most beautiful, educational, or amusing aspects of pathology – and you delivered. Welcome to our gallery tour of the most visually striking discipline in medicine!

False

The Pathologist
Subscribe

About

  • About Us
  • Work at Conexiant Europe
  • Terms and Conditions
  • Privacy Policy
  • Advertise With Us
  • Contact Us

Copyright © 2025 Texere Publishing Limited (trading as Conexiant), with registered number 08113419 whose registered office is at Booths No. 1, Booths Park, Chelford Road, Knutsford, England, WA16 8GS.