Congratulations to our new Pathology Chief Residents at Mayo Clinic @drchuanchen.bsky.social Chuan Chen, MD PhD and Saadiya Nazli 🎉🎉🎊🎊 @mayoclinicpath.bsky.social

#PathSky 22M, referred here for a “high-grade sarcoma” of the leg. Everyone agree? Wide excision plus chemo plus RT?

Great case. Thank you for sharing!

SMA negative.

#PathSky 15F, thumb mass. There are no relevant positive immunostains. However, FISH for DDIT3 amplification (not rearrangement) is positive. This is an excellent example of a GLI1-amplified sarcoma. This is a great paper from the MSKCC group. pubmed.ncbi.nlm.nih.gov/38934567/

MyoD1

GFAP.

#PathSky 30M, abdominal wall mass. Microcysts, bland round to spindled cells, thick-walled vessels. Positive for desmin, MyoD1, myogenin, and GFAP. Classic findings in EWSR1::PATZ1 sarcoma. Why isn’t this a fusion-positive RMS? Excellent question…https://pubmed.ncbi.nlm.nih.gov/38043789/

#PathSky Cystic leg mass, 31F. The outside pathologist thought this was probably a BFH/DF, but wasn’t sure how to explain the epithelium. This is a siderotic BFH with “adnexal induction”. You can get basically any imaginable adnexal proliferation. Siderophages are a good BFH clue.

Example of how BK nephropathy can be easily missed due to sampling. Dense inflammation only seen in deep medulla in this sample. Cortex unremarkable. Striking viral inclusions visualized. SV40 IHC positive. #renalpath #nephrology #pathsky

PRKAR1A

#PathSky 34M with a jet-black mass next to the seminal vesicle. Melanoma? A very occasional psammoma body was present, and expression of PRKAR1A was completely lost. Malignant melanotic nerve sheath tumor (previously “melanotic schwannoma”) in an unusual location.

Autolysis versus ATN in autopsy kidney. Same kidney. Better preserved areas show thin tubular epithelial cells till sitting on basement membrane = ATN. Dethatched lining tubular epithelial cells falling into lumen = autolysis/can't assess. #renalpath #pathsky #nephrology #autopsypath

GFAP

#PathSky Solid and cystic mass next to the liver in a 50F with no relevant hx or other masses. Once you think of it, extraspinal myxopapillary ependymoma in a rather odd location seems a good fit. Why not, right?

Excellent PKD gross photo taken by @clilleymd.bsky.social #nephology #pathsky #renalpath

Keratin

SMARCB1

#PathSky Hand mass, 32M. Bland spindle cell tumor with collagen trapping- just an FH, right? Also some less bland epithelioid areas. This is a predominantly spindled epithelioid sarcoma- “modulation” from epithelioid to spindled cells is an under appreciated morphological hallmark. See Comment.

S100

OCT2

#PathSky
Scalp mass, 33M. Just a nice example of soft tissue Rosai-Dorfman disease. I think this low power “pale->pink->blue” look is a good low power clue. In addition to S100 protein, Karen Rech’s group here at Mayo have shown OCT2 to be valuable in this dx. pubmed.ncbi.nlm.nih.gov/33177341/

I haven’t seen a #pathsky starter pack yet! I’ve tried to keep up with all of the new pathologists joining, but I know I have missed many! Please tag yourselves/others below and I will follow them and add them 😁 @kmirza.bsky.social @clilleymd.bsky.social @brettkurpiel.bsky.social go.bsky.app/6bWDSjT

Hello 👋 , I am Chuan joining #PathSky 😊🔬