Case Number : Case 742 - 19 Apr Posted By: Richard Logan

Flat topped papillomatosis and hyperkeratosis between the valleys. I feel that neutrophils and parakeratosis are secondary to impetiginization. Hence, acanthosis nigrigans..

Would like to see a PAS stain, though I would consider[i] tinea [/i]vs pityriasis versicolor (short filaments and spores)

I think the papillomatosis is normal for axillary skin. What is concerning me is the spore like structures in the third image, together with the neutrophils in the stratum corneum, the focal parakeratosis and the slight vesiculation in the second image, will make me consider fungal infection, will do PAS.

My thoughts exactly - agree with Dr Saeb.

Agree with Mona observation that a somewhat papillary pattern is a topographic cutaneous variation expected to the axillae.
Microscopic pictures show alterations almost restricted to the epidermis, including neutrophilic migration throughout epidermal layers and mounds of parakeratosis that house clusters of neutrophils.
Hyphae can be found at the interface between basket-weave and compact hyperorthokeratotic stratum corneum.
I would call this dermatophytosis.

I have the impression of seeing an hyphae in the fourth image at the right side.

Granular parakeratosis.

I think there may be mixed findings: incidental Pityrosporum and tinea corporis together.
1. Yeast are Pityrosporum (very small size, superficial location, clustering, and strong H&E staining).
2. Tinea: In the lower fourth photo, the hyphae show equivocally poorer H&E staining [they are invisible in some labs' H&E slides] and a pattern of aggressively penetrating, long vertically oriented hyphae segments (one in mid stratum corneum on right, two short ones in lower corneum on left and far left) more consistent with non-Pityrosporum fungus, like a dermatophyte [size=4]or C[/size][size=4]andida than Pityrosporum hyphae. [/size]

Tinea

Based on the dermatologist (in Warwick at least) being right in most instances I reported this as in keeping with acanthosis nigricans with secondary candidiasis. Fungal infection superimposed on ichthyoses is well recognised. There are at least 3 vertically orientated (well stained) hyphae in image 4 that are so typical of candida but I like Jim's suggestion of a second fungus like pityrosporum here. For me even allowing for the site there is an abormal acanthotic / hyperkeratotic process here. This is a recent case but I will try to get some follow-up and make an additional post in the week. A tip for the exams is that you must not stop at one diagnosis (the prevelance of second and third diagnoses in exams is very much disproportionate with real life) and you must at least address the clinical suggesions especially when they come from an experienced clinician. Apologies for delay but I was attending the 20th St John's Update in Dermatopathology yesterday. I am pretty sure Phillip organised or co-organised most of the first ten meetings and he will be glad to know the meetings are still going strong. Enjoy your weekends.

Update: On clinical review it was acanthosis nigricans. A bit smelly but mycology was negative - shows the value of histopathology!