Case Number : Case 682 - 24 Jan Posted By: Guest

I am struggling in the absence of the physical slide to view the silhouette etc. Given the inflammatory cells and the pleomorphism, I am considering a naevoid melanoma.

A dermal melanocytic nevus infiltrated by lymphocytes and histiocytes. I think it is a halo nevus, even though there is no notice of a border of depigmentation. The giant nevocytes suggest a long-standing lesion that became a source of concern after the arrival of the inflammatory cells, or it may mean reactive cytologic atypia. I did not find any mitotic figure.

Myxoid melanoma

I thought of nevoid melanoma...

Kidney may be a clue!!

LCH?

I would rule out a nevoid melanoma. I do not like the sheet-like syncytial growth pattern without apparent maturation.

agree on nevoid melanoma

Obviously melanoma has to be ruled out. So I did immunos and the proliferation of larger cells is negative for melanocytic markers and is positive for CD1a. So, I interpreted this as an isolated focus of Langerhans cell histiocytosis. The kidney has been biopsied, but I don't know what it showed.

And of course there is a nevus there, so I meant to say that this is a focus of LCH in association with a nevus.

[quote name='Dr. Hafeez Diwan' timestamp='1359062242']
Obviously melanoma has to be ruled out. So I did immunos and the proliferation of larger cells is negative for melanocytic markers and is positive for CD1a. So, I interpreted this as an isolated focus of Langerhans cell histiocytosis. The kidney has been biopsied, but I don't know what it showed.
[/quote]

Dr. Diwan. Thanks for this interesting and intriguing case. Do you think this phenomenon is recruitment of the LHC by the melanocytes? DC and LCH recruitment has been described in melanoma. http://www.ncbi.nlm.nih.gov/pubmed/12754747

Interesting :-)

Nice kidney shape nucleus(and horse shoe-kidney shapes) in this case were a clue
to do CD1a (just in case anyone missed my point). There is an eosinophil as well.

[quote name='Dr. Richard Carr' timestamp='1359103741']
Nice kidney shape nucleus(and horse shoe-kidney shapes) in this case were a clue
to do CD1a (just in case anyone missed my point). There is an eosinophil as well.
[/quote]

In the context of a melanocytic lesion, given that melanocytes can take any shape/ form, I have to say I did not even entertain LC's. So coming to my question Richard, would you call this 'LC's associated with a naevus' or 'LCH and a nevus'. When do a group of LC's qualify to be called LCH? LCH would mean that we have to screen for systemic involvement. But are naevus associated LC's associated with systemic disease (and therefore= LCH) or are they just reactive?

Very interesting comments. I run into this question often: when do LC's get to be enough to be called LCH. There can be solitary LCH; in my view, this aggregate is quite prominent and more than the usual scattered LC's. So I think this is LCH in a nevus. They could have been recruited and have formed a small nodule.

Hi Sasi,

Agree with Hafeez on this one I would call it LCH and collision of incidental naevus. Can be difficult to decide but this looks like a relatively pure nodule of LCH to me. I just can't believe this innocent presumed longstanding naevus has any relation to the LCH.

Interesting case!