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AndrewFolpe @folpe-mn-st.bsky.social · Jun 12

pubmed.ncbi.nlm.nih.gov/38621503/

GLI1 Coamplification in Well-Differentiated/Dedifferentiated Liposarcomas: Clinicopathologic and Molecular Analysis of 92 Cases - PubMed

GLI1(12q13.3) amplification is identified in a subset of mesenchymal neoplasms with a distinct nested round cell/epithelioid phenotype. MDM2 and CDK4 genes are situated along the oncogenic 12q13-15 se...

pubmed.ncbi.nlm.nih.gov

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AndrewFolpe @folpe-mn-st.bsky.social · Jun 12

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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AndrewFolpe @folpe-mn-st.bsky.social · Jun 12

Last 2

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AndrewFolpe @folpe-mn-st.bsky.social · Jun 12

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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AndrewFolpe @folpe-mn-st.bsky.social · Jun 12

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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AndrewFolpe @folpe-mn-st.bsky.social · Jun 12

It’s also got some bland spindle cell areas.

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AndrewFolpe @folpe-mn-st.bsky.social · Jun 12

#PathSky Laryngeal mass, older adult male. Primitive, highly vascular round cell neoplasm for the most part.

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AndrewFolpe @folpe-mn-st.bsky.social · Jun 5

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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AndrewFolpe @folpe-mn-st.bsky.social · Jun 5

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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AndrewFolpe @folpe-mn-st.bsky.social · Jun 5

#PathSky 53F with shortness of breath and “ground glass” pulmonary opacity. Not a hard dx, but a spectacular (if very unfortunate) case.

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AndrewFolpe @folpe-mn-st.bsky.social · May 30

So- desmoid fibromatosis with bizarre cells and p53 mutant pattern- r/o Li-Fraumeni syndrome.

Happy Friday!

pubmed.ncbi.nlm.nih.gov/36908221/

Desmoid Fibromatosis With TP53 Mutation and Striking Nuclear Pleomorphism - PubMed

Desmoid fibromatosis is a myofibroblastic neoplasm of intermediate biologic potential, which has a strong predilection for local recurrence but does not metastasize. Arranged in long, sweeping fascicl...

pubmed.ncbi.nlm.nih.gov

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AndrewFolpe @folpe-mn-st.bsky.social · May 30

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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AndrewFolpe @folpe-mn-st.bsky.social · May 30

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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AndrewFolpe @folpe-mn-st.bsky.social · May 30

#PathSky Abdominal wall mass, middle aged woman. Women basically only get 3 abdominal wall tumors, so it’s got to be a desmoid, DFSP or endometriosis. Classic desmoid morphology, aberrant nuclear beta-catenin. I can hear the cries of “boring..”

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AndrewFolpe @folpe-mn-st.bsky.social · May 23

#PathSky Someone shared a chest wall Ewing sarcoma with me today, and I queried them about exactly what they were Askin. I should probably retire today.

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AndrewFolpe @folpe-mn-st.bsky.social · May 20

I wrote a complaint.

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AndrewFolpe @folpe-mn-st.bsky.social · May 20

Pics would be nice, right?

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AndrewFolpe @folpe-mn-st.bsky.social · May 20

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/

A Novel SS18-SSX Fusion-specific Antibody for the Diagnosis of Synovial Sarcoma - PubMed

Synovial sarcoma (SS), an aggressive soft tissue sarcoma with a predilection for the extremities of young adults, harbors the pathognomonic t(X;18)(p11;q11) translocation, resulting in SS18-SSX rearra...

pubmed.ncbi.nlm.nih.gov

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AndrewFolpe @folpe-mn-st.bsky.social · May 20

#PathSky Middle aged woman, leg mass. It all looks like this. More nuclear palisading/ Verocay bodies than you’ve seen in your entire career. Nerve sheath? S100/Sox10 negative. LMS? Negative for all the muscle markers. Any other ideas?

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AndrewFolpe @folpe-mn-st.bsky.social · May 15

Oh, ok. Thx.

AndrewFolpe @folpe-mn-st.bsky.social · May 15

?

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AndrewFolpe @folpe-mn-st.bsky.social · May 14

Oops, I forgot the MDM2 photo.

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AndrewFolpe @folpe-mn-st.bsky.social · May 14

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/

Dedifferentiated Liposarcoma With Epithelioid/Epithelial Features - PubMed

Dedifferentiated liposarcoma (DDLPS) demonstrates a variety of growth patterns, and their histologic resemblance to other spindle cell mesenchymal tumors has been widely recognized. However, epithelio...

pubmed.ncbi.nlm.nih.gov

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AndrewFolpe @folpe-mn-st.bsky.social · May 14

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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AndrewFolpe @folpe-mn-st.bsky.social · May 14

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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