Case Number : Case 1029 - 3rd June Posted By: Guest

? Atypical melanocyte proliferation within basal layer , ? Focal supra basal ascent... Or ? basal keratinocyte atypia? I think I will do Melan A first for this lesion...

This is not an easy case. I´m thinking there is some atypical keratinocytes at the basal layer with palisade Deep sections could show us a superficial CBC

Inspired by the comment of Dr Igor, may be the empty spaces are clue of BCC, mucinous artefacts !!!!!!

Difficult...not sure if the epidermal changes are significant or dermal!
Wondering about the nature of the superficial dermal vacuoles ?lymphatics ?pseudolipomatosis cutis

The clinical diagnosis was squamous cell carcinoma, if it helps.

My first impression is superficial lymphatic malformation, aka lymphangioma circunscriptum, but the typical clinical presentation of grouped vesicle-like papules doesn’t fit on an impression of squamous cell carcinoma. I’m not sure about relevant epidermal abnormalities. Looking forward for new insights.

Bowen's ??

[size=4]Agree this is a challenge. I'd consider an unusual presentation of lichen aureus / pigmented purpura, or MF. As Igor suggested, the edge of an epidermal neoplasm such as BCC or SCC in situ, although the epidermis looks more reactive than neoplastic to me.[/size]

[size=4]The centrally atrophic epidermis looks like benign reactive inflammatory changes, with sparse lymphocyte exocytosis, spongiosis, hypergranulosis, hydropic changes, and compact hyperkeratosis. There is a lichenoid chronic inflammatory infiltrate (focally hyperchromatic lymphocytes, and more peripheral aggregates of plasma cells or lymphoplasmacytoid cells) with scattered clear, slightly refractile, oil-droplet-like, focally compartmented spaces with what appears to be foamy histiocyte (or adipocyte-like) vesiculated large pale nuclei at the periphery; these agree with this might represent adipose tissue, foreign-body oil, pseudolipomatosis vs.lymphangioma. There is subtle sparse brown pigment in the dermis, which may be non-specific melanin from inflammation, vs. hemosiderin [last photo]. [/size]

Mycosis fungoides.a typical variant.

I think this is superficial lymphangioma (lymphangioma circumscriptum). Sometimes, the epidermis overlying these lesions looks warty, which is true in our case and also explains the clinical presentation.

Lymphangiectasia.

Thanks, everyone, for your opinions on this case. As I am on holiday, I don't have direct access to my report on this case, so I don't want to mislead anyone on my exact diagnosis. Initially, I thought it might have been the sequela of a steroid injection because of the lipid. Yet, S100 protein outlined cell membranes in the lesion, so these appear to be authentic adipocytes. This led me to conclude that this might be be an unusual hamartoma. I can tell you that this was not SCC or Bowen's disease or mycosis fungoides.

If everyone will bear with me for a few days, when I return to my office, I'll state the full report for further discussion.

What about lichen planus like keratosis?

I'm back in my office, and here is what I stated about the lesion. Further discussion is welcomed.

MAH

--------

SKIN, RIGHT POSTERIOR THIGH , SHAVE BIOPSY :
[b]-- ACTINIC KERATOSIS ASSOCIATED WITH NEVUS LIPOMATOSIS [/b]
[indent=1][b]COMMENT:[/b] The differential of vacuolated cells in the papillary dermis includes lipid deposits in the papillary dermis vs. authentic adipocytes. In this case, the adipocytes are, in fact, authentic because the cells in question contain nuclei and are rimmed by S-100 positivity. I believe that the argument for actinic keratosis in this case centers on the fact that there are slight jumbled qualities to the basal layer of the epidermis, along with some nuclear variations in size and shape in the basal few layers. [/indent]


Microscopic:

The specimen from the right posterior thigh, there is a shave that contains adipocytes within the papillary dermis. The epidermis associated with this is slightly acanthotic, and the basal keratocytes are slightly enlarged, and they are associated with a minor amount of spongiosis. There is some chronic inflammation around the adipocytes. I don't identify any nuclear pleomorphism full-thickness in this lesion. The heterogeneous quality of the basal keratocytes might be explained also by some degree of rubbing, because of the compressed cornified layer in question. S-100 protein confirms that these are indeed adipocytes, as the marker stains the rims around these cells. Additionally, a number of them contain nuclei, which also corroborates these vacuolated cells as being adipocytes. CD31 is negative in these vacuolated cells, militating against them being vascular. Levels were taken to deplete all the tissue in the block, and in a few of the sections there are clonal qualities to portions of the epidermis, and a few enlarged keratocytes compatible with an actinic keratosis. There is only minimal solar elastosis identified within the papillary dermis. Recuts were obtained to deplete all tissue in the block.

I was all the time worried about the basal layer !!!!

I think we saw similar fat cells high in the dermis (anatomically located on the calf) last week in a "lichenoid keratosis" or regression reaction in a superficial BCC. Not sure I would put to much emphasis on them but fun to speculate.