Multiple images in this post...swipe or use arrows to see them all.
Gross photo: https://kikoxp.com/posts/10214
This was a large thigh mass in an adult. Immunostains for s100, pancytokeratin, desmin, and actin were negative. See links below for more about how I work up high grade pleomorphic sarcomas.
The abundant inflammation with intracytoplasmic neutrophils in the tumor cell cytoplasm (emperipolesis) is a curious finding that I've seen occasionally in UPS and various other high grade pleomorphic sarcomas (although never as robust as in this case!). It's a good reminder that emperipolesis does not always equal Rosai-Dorfman disease! Some of the intracytoplasmic neutrophils look degenerated/dying, so you could take an alternative interpretation that this finding is actually true hemophagocytosis rather than emperipolesis. Interestingly, in this case, the patient had night sweats and a high WBC count in the peripheral blood...I suspect that those findings were likely related to this brisk inflammatory response.
The huge viral inclusion-like nucleoli and the brisk inflammation made me consider myxoinflammatory fibroblastic sarcoma (MIFS) in the differential diagnosis. However, the large size, brisk mitotic rate, lack of myxoid change, and non-acral anatomic site all taken together made me more in favor of UPS.
See also:
Undifferentiated sarcoma / Undifferentiated pleomorphic sarcoma (UPS)
Gross photo: https://kikoxp.com/posts/10214
This was a large thigh mass in an adult. Immunostains for s100, pancytokeratin, desmin, and actin were negative. See links below for more about how I work up high grade pleomorphic sarcomas.
The abundant inflammation with intracytoplasmic neutrophils in the tumor cell cytoplasm (emperipolesis) is a curious finding that I've seen occasionally in UPS and various other high grade pleomorphic sarcomas (although never as robust as in this case!). It's a good reminder that emperipolesis does not always equal Rosai-Dorfman disease! Some of the intracytoplasmic neutrophils look degenerated/dying, so you could take an alternative interpretation that this finding is actually true hemophagocytosis rather than emperipolesis. Interestingly, in this case, the patient had night sweats and a high WBC count in the peripheral blood...I suspect that those findings were likely related to this brisk inflammatory response.
The huge viral inclusion-like nucleoli and the brisk inflammation made me consider myxoinflammatory fibroblastic sarcoma (MIFS) in the differential diagnosis. However, the large size, brisk mitotic rate, lack of myxoid change, and non-acral anatomic site all taken together made me more in favor of UPS.
See also:
Undifferentiated sarcoma / Undifferentiated pleomorphic sarcoma (UPS)
Video (101): https://kikoxp.com/posts/4554
Video (101): https://kikoxp.com/posts/9839
WSI digital slide: https://kikoxp.com/posts/6841
Sample Pathology Report Template (biopsy): https://kikoxp.com/posts/9915
Sample Pathology Report Template (resection): https://kikoxp.com/posts/9916
Myxoinflammatory fibroblastic sarcoma (MIFS)
Video (discussed in this review video): https://kikoxp.com/posts/9104
WSI digital slides: https://kikoxp.com/posts/5128
Video (RDD 101): https://kikoxp.com/posts/4288
Video (short): https://kikoxp.com/posts/6854
Video (fibrotic burnt out RDD mimicking “inflammatory pseudotumor”): https://kikoxp.com/posts/6290
Video (RDD of bone discussed in this review video): https://kikoxp.com/posts/4468
A complete organized library of all my videos, digital slides, pics, & sample pathology reports is available here: https://kikoxp.com/posts/5084 (dermpath) & https://kikoxp.com/posts/5083 (bone/soft tissue sarcoma pathology).
Check out my #dermpath Survival Guide book: http://bit.ly/2Te2haB
Level 1 Genius | Physician
March 24, 2022 at 5:57pm