Case Number : Case 1624 - 15 September Posted By: Guest

Primary granulomatous lymphocyte poor dermal inflammation, frequently surrounding nerves. There seems to be some interface change and dermal edema in picture 2. The differentials include: Leprosy, non-tuberculoous mycobacterial infection, sarcoidosis, and less probable syphilis (due to lack of plasmocytes and mainly granulomatous infiltrate). Clinicopathological correlation is really important here as well as eventual PCR, culture. Would still perform ZN, and Warthin-starry/ IHQ for treponems. Here a nice article of entities with perineural inflammation. I think my favourite diagnosis is first leprosy and second sarcoidosis. Everything (rash and nodules) is confined to the lower arm or the rash is systemic? Because if confined to the arm then atypical mycobacterial infection is algo a good consideration.

Agree with Raul, i consider more leprosy and atypical mycobacterial infection.further studies are needed.

Agree with above. Histoid Leprosy could be a good diff.  

DD 
mastocytosis

Yes this is case of leprosy. 

The patient was a student from Srilanka. As this is quite an uncommon diagnosis in this part of the world, the dermatologists were not quite familiar with its cutaneous spectrum and did not suspect the diagnosis. Following the histology report, the infectious disease consultants were involved and the patient had quite typical anaeasthetic patches, ulnar nerve thickening and early clawing of hand. The AFB was negative on the histology section but a slit skin smear was positive (1+).

Cant claim to have any expertise in classifying leprosy, as this is the only case I have ever diagnosed in UK! But from my early pathology years in India where I did see quite a few cases, I classified this as a Borderline Tuberculoid leprosy.