In this section we have spot diagnoses posted on a daily basis since June 2010, now over 1700! You can review the archived cases and read the suggested diagnoses by users and the final comment by Dr Uma Sundram, the Editor-in-Chief and main spot diagnosis host. Case are uploaded each week day by 10 a.m. UK time with the correct diagnosis will generally be posted at 8 p.m. UK time. Why not view the most recent spot diagnosis and proffer a diagnosis?

Sign in to follow this  

Case Number : Case 2258 - 7 February 2019 Posted By: Raul Perret

Please read the clinical history and view the images by clicking on them before you proffer your diagnosis.
Submitted Date :
   (0 reviews)

55y old female with a 40 mm subcutaneous knee mass

Sign in to follow this  

User Feedback


vincenzo

Posted (edited)

Blunt anded nucleus and perinuclear clear halo, make me think of subcutaneous leiomyosarcoma. 

Edited by vincenzo

Share this comment


Link to comment
Share on other sites
Alex-Ventura-Leon

Posted

My possibilities are Leiomyosarcoma, Sinovial Sarcoma and least likely MPNST

Waiting for IHC and more comments.

Share this comment


Link to comment
Share on other sites
Dr. Mona Abdel Halim

Posted

Leiomyosarcoma is my first thought

Share this comment


Link to comment
Share on other sites

The cells, even though showing nuclear hyperchromasia, are pretty uniform ovoid and focal "herringbone" arrangement. increased mast cells are noted. I am in favor of monophasic synovial sarcoma given the location of around knee. I will order some stains including especially Keratin, EMA and TLE1. of course, add other spindle cell tumor markers like SMA, DESMIN, CD34 etc.. if you have molecular check t (X;18) translocation. 

Share this comment


Link to comment
Share on other sites

MyoD1 positivity and focal Myogenin positivity...Spindle Cell Rhabdomyosarcoma?

Share this comment


Link to comment
Share on other sites
Alex-Ventura-Leon

Posted

Yes, Spindle cell Rhabdomyosarcoma after IHC.

I´ve never seen one in real life. Nice case. Thanks

Share this comment


Link to comment
Share on other sites
Victor Delgado

Posted

Every day learning from you guys. Nice case, thanks for sharing.

Share this comment


Link to comment
Share on other sites
Raul Perret

Posted

Yes, this was a case of spindle cell rhabdomyosarcoma. These rare neoplasms have a dual peak incidence in infants and adults. Most tumors that develop during infancy have a  good prognosis, are usually localized in the head and neck or the paratesticular area and frequently have NCOA2 or VGLL2 réarrangements. On the other hand, adults usually present aggressive tumors that frequently harbour MYOD1 mutations. More importantly, no matter the age of presentation, MYOD1 mutated tumors seem to have an overall worse prognosis . 

Morphologically, spindle cell RMS frequently looks like leiomyosarcoma because of its pink colour at low power and fascicular disposition of cells. However, unlike LMS, spindle cell RMS tends to be more cellular and fascicles rarely intersect at right angles. Do keep in mind that some cases are extremely hypercellular (blue tumors) and others can be largely sclerotic, sometimes with a pseudovascular morphology. The latter would be considered in the spectrum of sclerosing rhabdomyosarcoma, a morphological variant that is very closely related to spindle cell RMS.

Finally, do not forget that to confirm the diagnosis, appart from the morphology, you need the expression of Myogenin or MYOD-1. The latter is usually expressed more diffusely than the former like depicted in this case.

Have a great day

Share this comment


Link to comment
Share on other sites


Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now