Case Number : Case 1475 -18 February Posted By: Guest

Early toxic epidermal necrolysis. To my eyes there is an overlap in this photos of TEN with EM but i favour the first one.Probably the retroperitoneal mass is a lymphoma, there are associations between TEN and lymphomas, tough it would be important to know if the patient recieved medications at the moment of the rash including chemotherapy.

Agree with EM/TEN or PNP for IMF study.

That is a good suggestion Mona. On morphology alone we would not be able to differentiate these lesions

Agree, although i favour Erythema Multiforme actually, because of focal, not confluent epidermal necrosis. 

I think hyperkeratosis speaks against erythema multiforme and TEN. I go with paraneoplastic pemphigus.

in Figure 4, probably single acantholytic cell present. 

From the history, probably this is a case of Paraneoplastic pemphigus.

IF will help.

Yes, this is a case of Paraneoplastic Pemphigus.

The Direct IMF showed intercellular IgG and linear C3 along dermo-epidermal junction. (this combination being typical of PNP). The retroperitoneal mass was a sarcoma with lung mets.

Mona has already summarised the key features well, in particular that one may not find any acantholysis at all. It is important to keep this entity in the back of your mind when faced with EM like histology as PNP may precede diagnosis of malignancy. Unfortunately, the disease is multi systemic and has a rapid downhill course with high mortality. (as was also the case in this patient).