folpe-mn-st.bsky.social
I like my wife and family, bikes, music, dogs, baking bread and soft tissue tumors. Only the last here though.
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pubmed.ncbi.nlm.nih.gov/38621503/
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This is classic morphology for a GLI1 coamplified differentiated liposarcoma with perineurial-like whorls. So now the MDM2 amplification makes sense. The current tumor is showing essentially classical features of a GLI1 amplified soft tissue sarcoma. So the morphology/molecular explain each other.
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Last 2
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Well, it turned out he had a tumor in the same laryngeal location a few years ago, diagnosed as a “fibroinflammatory lesion with some features of IgG4 disease”.
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A big panel of IHC was negative. For somewhat unclear reasons, MDM2 FISH was ordered and was amplified. Does this make any sense?
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It’s also got some bland spindle cell areas.
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Epithelioid angiosarcoma with extensive intravascular growth. Obviously there must be a right sided primary. There’s supposed to be a liver mass.
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Just because the ddx includes intravascular lymphoma (at one time known as “intravascular angioendothelioma”), the first pic is CD20. The others of course are CD31 and CD34.
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So- desmoid fibromatosis with bizarre cells and p53 mutant pattern- r/o Li-Fraumeni syndrome.
Happy Friday!
pubmed.ncbi.nlm.nih.gov/36908221/
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There is a single case report of a desmoid occurring in a Li-Fraumeni patient, with identical morphology. p53 IHC done on this case shows a null/mutated pattern.
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Fear not. It’s also got these really bizarre cells, all over the place. Those don’t belong in a desmoid! Not a desmoid? Or is there another explanation?
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I wrote a complaint.
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Pics would be nice, right?
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It’s diffusely positive for SS18-SSX fusion protein and SSX c-terminus antibody. Monophasic synovial sarcoma, with nuclear palisading. Yes, I’ve seen this before. No, not anywhere near this much. pubmed.ncbi.nlm.nih.gov/32141887/
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Oh, ok. Thx.
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?
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Oops, I forgot the MDM2 photo.
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This is actually a rather spectacular example of dedifferentiated liposarcoma with epithelioid/ epithelial features, a rather rare but reported phenomenon. pubmed.ncbi.nlm.nih.gov/28719466/
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Now, it turns out that she has a clinical history of retroperitoneal dedifferentiated liposarcoma, with multiple local recurrences over a decade. Here’s the MDM2 IHC, diffusely and strongly positive. FISH was also done and 100% of cells showed high level gene amplification.
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Metastatic carcinoma, obviously. A big clinical work up didn’t identify a primary tumor, and a very broad panel of site-directed markers, including neuroendocrine markers, was negative. So, yet another carcinoma of unknown primary, right?
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Took me a while…
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So this truly is a superficial MPNST arising in a neurofibroma (an almost always wrong dx!) If you’re wondering, absent EED/SUZ12 mutations explain normal H3K27me3.
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Well, although I usually try to emphasize morphology, this is one where the molecular bails us out. It showed very low TMB (unlike melanoma), had two different NF1 mutations, lacked melanoma-associated mutations (other than NF1), and had loss of CDKN2A and B.
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So we’re done, right? “Spindle cell melanoma- next case”. Oddly, SOX10, however was absent in about 50% of cells, as seen in MPNST. H3K27me3 expression was retained, which doesn’t help. PRAME was negative.
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In the skin, this morphology almost always points towards spindle cell melanoma. Now, if you looked around, there were small areas resembling a pre-existing neurofibroma, but this is an “entry level” pitfall in the diagnosis of spindle cell melanoma. S100 protein is also diffusely positive.
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Degenerating vegetable. Likely a ruptured diverticulitis with a big reactive soft tissue mass. Happy Friday!!
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Those of you following my cases know the answer is usually “look at the slides some more”.
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pubmed.ncbi.nlm.nih.gov/9578090/
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This of course is what we now call “myxoinflammatory fibroblastic sarcoma”. Originally reported as “Inflammatory myxohyaline tumor of distal extremities with virocyte or Reed-Sternberg-like cells”. I think this older name helps us remember the distinctive diagnostic features of this sarcoma.
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And then there are these mucous nodules, with very nice pseudolipoblasts. Diagnosis?
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There are some odd looking cells around the hyaline fibrosis, though. Some with really big nucleoli.
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At high power, the cells in this mass are rather bland, epithelioid, and somewhat myoid. HMB45, Melan A and cathepsin K are positive. Lipomatous angiomyolipoma. These can be sneaky….
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Lyle seems fierce. Be safe.
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He turned out to have myelodysplasia and myelofibrosis. This is a “sclerosing extramedullary hematopoietic tumor”, basically dysplastic EMH presenting as a soft tissue mass. pubmed.ncbi.nlm.nih.gov/10632487/
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Any immunos you might want? How about CD61, hemoglobin and CD43? Any hx you might want?
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About as good as it gets for inflammatory rhabdomyoblastic tumor, the first and only skeletal muscle tumor of borderline malignancy. They can also progress to a unique rhabdomyosarcoma subtype.
pubmed.ncbi.nlm.nih.gov?term=Folpe+i...
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Oncoscan SNP assay showed near-haploidy with retained disomy of 5,12,18,20-22.
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IHC: tons of CD163-positive histiocytic, desmin expression in the large cells, extremely rare MyoD1-positive cells, caldesmon- negative.