Case Number : Case 2921 - 16 September 2021 Posted By: Saleem Taibjee

The combination of congenital heart defect, pan-hypopituitarism and neutrophilic lobular panniculitis certainly suggests a genetic syndrome.  Even with the help of Dr. Google I haven't been able to piece these three elements together under a unifying diagnosis.  I await the answer with interest!

Neutrophilic pannicliutis with infiltrate extending into the dermis makes me think of Alpha-1 Anti-trypsin deficiency. But could not connect it to congenital heart defect and pan-hypopituitarism. 

The Kikutchy-.Fujimoto disease doesn’t contain so much pmnucleated elements, HSC-LC Histiocytosis fits the hypopituitarism, but not the age and I don’t see any Langherans cell ( as I know them ). alpha1-antitrypsin deficiency doesn’t fit the age. So agree with the awaiting the answer. 

Infective panniculitis is most likely. Special stains for bugs and culture for bacteria and fungi may help.

Infective cause needs exclusion first? it is unilateral on leg, is the child on oral steroids or other immunosuppresive medication or know to have immunodeficiency disorders? rapidly growing Non-Tuberculous Mycobacteria (NTM) species worth consideration depending on the context. 

Yes, well done. This is a recent case. It is very easy to become distracted by the young age and various co-morbidity which was provided by the clinical team on the histology request form, and wonder if there is a rare syndrome as a unifying diagnosis.

But the suppurative granulomatous pattern on histology should still prompt a 'standard' approach to the histological differential diagnosis.

The ZN stain is shown below. Interestingly, the stain had just come through at the time of the MDT meeting in which I was asked to present the histology. I had already raised the possibility of infection with the clinician, and we could all see the fairly conspicuous acid-fast bacilli together when I opened the digital scan of the ZN stain live at the meeting. It does show how far the resolution/quality fo digital scanning has come on. These days, I hardly ever need to resort to seeing the glass slides for those cases which I report digitally.

As Saman states, I too had concluded that this was likely to be an atypical mycobacterium in the context of young child with a probable degree of immunodeficiency. Unfortunately culture was negative and the patient was treated empirically, so I can't tell you the specific organism in this case.

BW

Saleem