July 2009 – Case of the Month #4

 

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Website news:

 

(1) We have a new shortcut URL - Dermout.net (dermout.com was already taken).  If you don’t want to bookmark our website, or make it your Home Page, just type this into your browser to access our website.

 

(2) We have split Soft Tissue Tumors into 3 chapters, and updated Soft Tissue Tumors-Part 2 (click here), which includes Fibrohistiocytic and Adipose tissue tumors.  This chapter is also in our new format, in which each topic is a separate page that is accessed by clicking on the link in the Table of Contents or Index.  The advantages are faster loading of each page, easier to read pages with less scrolling, and the inclusion of thumbnails for most images.  We will be moving all chapters to this format over the next year.

 

(3) Congratulations to Dr. Marc Klein, Ludington, Michigan, for winning our jobs email drawing.  We sent him a check for $50.  We plan to announce another drawing next month as part of our exhibiting at the July AAD conference.

 

(4) Visit our Books page (or click here) to see the new books recently added, including books on cosmetic dermatology, surgery and infectious disorders.  We will be at the AAD Conference in Boston on July 30 to August 1.  Stop by Booth #202 and say hello.

 

We thank Dr. Ankur Sangoi, Stanford University, Stanford, California (USA) for contributing this case.  We invite you to contribute a Case of the Month by sending microscopic images in JPG or GIF format, with a clinical history and any other images (gross, dermoscopy, immunostains, etc.) that may be helpful, to NatPernick@Hotmail.com.  We will write the discussion (unless you want to), list you as the contributor, and send you a check for $35 (US) after we send out the case.  Please only send cases with a definitive diagnosis. 

 

Dermatology Case of the Month #4

 

Clinical history

 

A 64 year old woman had pruritic, erythematous plaques on her abdomen and back that appeared and disappeared randomly.  She also had a long history of smoking.  The clinical concerns were mycosis fungoides or morphea (localized scleroderma).  An ellipse of skin on the abdominal wall was excised.

 

Micro images: image #1#2#3#4  

 

What is your diagnosis? 

 

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Diagnosis:

 

Consistent with erythema gyratum repens

 

Discussion

 

Microscopically, the epidermis shows focal acanthosis, parakeratosis and spongiosis.  There are no blisters or intraepithelial microabscesses, and exocytosis (inflammatory cells in the epidermis) is minimal.  The dermis shows a patchy and perivascular infiltrate which consists of small, round, mature appearing lymphocytes, as well as some histiocytes and eosinophils.

 

This case illustrates a problematic area for many dermatopathologists - interpreting an inflammatory dermatosis.  In these cases, clinical input is crucial.

 

Erythema gyratum repens is very rare.  The diagnosis is important because it is associated with existing or subsequent internal malignancy in 80% of cases (Am J Med Sci 2001;321:302, Clin Exp Dermatol 2001;26:510).  It typically causes concentric and parallel bands of erythema and scale (“wood grain pattern”) on the trunk and extremities (gross image #1#2#3).  The rash migrates at the rate of 1 cm per day and is very pruritic.  It is also associated with ichthyosis (16%) and hyperkeratosis (10%).  The histology, as illustrated above, is non-specific.

 

The differential diagnosis include erythema annulare centrifugum.  This is a hypersensitivity reaction that also grows over a period of weeks, is mildly pruritic and affects the trunk and proximal extremities.  Most cases resolve within six weeks.  Histologically, there may be a superficial perivascular infiltrate, but it shows tight cuffing of the inflammatory cells around swollen endothelial cells, and focal extravasation of red blood cells into the papillary dermis.  The deep variant shows a “coat-sleeve-like” pattern of perivascular infiltrate in the middle to deep dermis. 

 

The cause of erythema gyratum repens is unknown.  It may have an immunological basis, based on the occasional presence of C3, C4, and IgG at the basement membrane zone with direct immunofluorescence.  It may also be considered a paraneoplastic syndrome.  Treatment of the underlying malignancy may cause remission.  Cetirizine hydrochloride may be effective treatment (J Dermatol 2002;29:731).

 

References: eMedicine

 

 

Nat Pernick, M.D., President
DermatologyOutlines.com
30100 Telegraph Road, Suite 408
Bingham Farms, Michigan (USA) 48025

Telephone: 248/646-0325
Fax: 248/646-1736
Email: NatPernick@hotmail.com