Case Number : Case 2961 - 11 November 2021 Posted By: Saleem Taibjee

Spindle cell lipoma at it's characteristic location and patient profile. 

Nice ropey collagen, mast cells, fish schools in a fibrolipomatous tumor should suggest a SCL, shouldn’t it?

Spindle cell lipoma

Yes. Spindle cell lipoma

agree to  Spindle cell lipoma

Yes. This is spindle cell lipoma. The CD34 was nice and positive (see below).

I was quite struck by the variable size of adipocytes in this case (3rd and 4th images above), and very focal lipoblasts (last image) above. I was previously taught that variable sized adipocytes should prompt a close look at a fatty tumour, and can be a clue to malignancy. Since this was a striking feature in this case, I shared it with Dr Raul Perret. He has helpfully refreshed/revised my understanding of this sign. He regards the variable size of adipocytes as a clue to the neoplastic nature of the adipocytes (i.e. fatty tumour lineage), but has reassured me that it does not generally indicate malignancy. Hence the reason for sharing this otherwise typical case.

BW Saleem

Thanks for this educating case, Saleem.