Case Number : Case 2294 - 29 March 2019 Posted By: Dr. Richard Carr

Looks like a well circumscribed, possible encapsulated lesion of spindle cell neoplasm, the prominent vasculature changes with hyalinization of vessel wall raise a possibility of Schwannoma. there is also fat metaplasia and SCL like changes noted. I will do my favorite "triplet" stains for neural tumor--S100, CD34 and EMA.

Angiomatous spindle cell Lipoma. Ref:  Zamecnic M,  Michal M. Pathol Int. 2007;57: 26-31.

Agree with Henry looks neural and my spot would be Ancient Schwannoma, but I am intriguing about the possibility of Spindell Cell Lipoma.

Prefer neural, ancient change in neurofibroma? Agree with the triplet stains mentioned by Henry. 

Intriguing case! Some features look like a pleomorphic(but not pleomorphic)angiectatic hyalinizing tumor; some other features are reminiscent of SCL. Waiting for the answer.

Spindle cell lipoma then. 

Yes, the CD34 support the diagnosis of SCL. 

Anil was rigth

The lesion appears to be positive for ER/PR, which is usually negative in SPL. I do not really appreciate ropey collagens in the lesion. The vessels with hyaline material in the wall are also unusual for SPL. So there are some features that do not quite fit a SPL.

Every time I see a lesion that looks like a schwannoma because of the hyaline vessels, I automatically think of a cellular angiofibroma, particularly in the vulvar area. The fat at the periphery of the lesion is also quite characteristic for a cellular angiofibroma. The hand is definitely an unusual site for a cellular angiofibroma, but that's the beauty of pathology, we always have to consider the unusual diagnosis  if all the options do not make complete sense (Again RB1 might help).

Great job anh.

Here's the correspondence between me and our dermpathpro soft tissue guru! (I'm Rick or Ricky to my close friends)

I favoured cellular angiofibroma (atlhough it’s not that cellular and the vessels were rather geographically located around the peripheries not throughout the bland fibro-fatty areas).

DDx: Mammary type myofibroblastoma, spindle cell lipoma etc.

I’d guess it was a RB protein lost lesion though.

What do you think?

RAC

Hey Rick,
I agree with your interpretation of this lesion. 
It looks like a benign CD34 + spindle cell neoplasm in the lines of RB1 deficient neoplasms (spindle cell lipoma / mammary type myofibroblastoma / cellular angiofibroma).
Topography is odd for this familiy of tumors but there aren't many differentials, particularly if there is strong and diffuse positivity for CD34 and no staghorn vessels.
Based on the hyalinized vessels it looks most like cellular angiofibroma.
Cheers,
Raul

Hey Rick,
I have  recently   read  that spindle cell lipoma may rarely have hyalinized vessels and mimick cellular angiofibroma.
This is not astonishing as both of these neoplasms share cytogenetic anomalies.
 I still think that this lesion resembles more cellular angiofibroma than spindle cell lipoma (ropey collagen is absent as well as myxoid areas).
Cheers,
Raul

Answer for 2289 now posted. Apologies for delay.  I'm off to Florida for the WHO classification up-date organised by Artur Zembowicz. Do say hello if you're attending. I'm also planning to play a bit of golf the week before!

I just sent a case of cellular angiofibroma that mostly grows in the rectal wall to Dr. Christopher Fletcher. Same staining pattern but not cellular at all. Dr. Fletcher still called it cellular angiofibroma although the tumor grows into the wall of the rectum. Dr. Fletcher still said it's benign, not to worry. So although the name is cellular angiofibroma, some are not cellular at all. Just keep that in mind.

Dr. Carr,

Welcome to Orlando, my city. This is a great time to play golf. I heard Disney has very nice golf fields. But I don't play golf  but it's Disney, so I am pretty sure everything is nice . I will also go to Dr. Artur Zembowicz meeting. So convenient because I live in Orlando. Hopefully I see you there.

Anh