Case Number : Case 1999 - 2 Feb 2018 Posted By: Dr. Richard Carr

This is a neutrophilic lobular panniculitis with spillover into the septa. It's very difficult to give etiologic diagnosis without clinical details and correlation. It could be infectious, factitious, due to alpha 1 antitrypsin deficiency or due to myelodysplastic syndromes. Could not identify the eosinophilic structure in the last image. It could be a foreign body or trophozoit form of some parasite like acanthameba. Another interesting possibility is that of acute infectious id panniculitis ( Magro et al J Cut Path 2008;35:941-46). Would be interesting to know the details from Dr Carr!

To add to the above comment, PAS and Fite Faraco stains would give some more clues

Thinking also of infectious panniculitis. Suspecting fungal structures in the last image. Special stains are needed. 

acute panniculitis pattern but also angiocentric. Agree with all above comments. The last figure show lot of neutrophilic debris but also some clusters of quite atypical cells with irregular hyperchromatic nuclei and clear cytoplasm on the right side of the vessel. So would like to rule out a NK/-T or T cell lymphoma. EBV stain?

Cutaneous lymphomas with a panniculitic presentation, angiocentricity/angiodestruction is striking in this case. Main players are Subcutaneous Panniculitis-like T-Cell Lymphoma (SPTCL) and Gamma Delta T-Cell Lymphoma (GDTCL).

Needs complete immunophenotyping including Beta F1 and proper correlation with the clinical features to finalise the diagnosis. Based on what is availabe so far and CD8+ cells, SPTCL slightly favoured though the degree of the vessle destruction is a bit unusual for a classic SPTCL. 

Agree with Saman. 

Interesting!

so it is a subcutaneous panniculitis like T cell lymphoma

We reviewed this histology because the patient presented with a new rash (that was eczematous). This case had been reported initially rather cryptically and referred for a specialist opinion to a national haematological centre who confirmed T-cell receptor gene re-arrangements. It was reported as a T-cell lymphoma CD4+ve (unusual for panniculitis-like T-cell lymphoma). The original IHC was confusing so we repeated it and the larger cells are CD8+ve. We don't have Beta-F1 so cannot confirm but given that the patient presented with a solitary lesion and is alive and well some 9 years later we concluded it was in keeping with a panniculitis-like T-cell lymphoma.

Thanks for the illustrative case! We've seen cases where the initial diagnosis of SPLTCL was quite difficult as the infiltrate was rather subtle in the first biopsy.

Wonder if there was any erythrophagocytosis in this case.

Anyone encountered cases with initial lupus-like morphology - with interface reaction pattern and increased mucin? Seems to be reported that sometimes there might be SPLTCL on subsequent biopsy.

No erthyrophagocytosis seen Elaine. Yes I've seen rare cases of lupus changing to SPLTCL.