Erythema Annulare Centrifugum: Deep Variant with Vasculitis Like Histopathology

Sir,

A 22-year-old girl presented with itchy raised skin lesions on the back since the past 2 years. The lesions started initially on the back and increased in size gradually, with central clearing to form annular red, raised lesions. One year after the onset of lesions on the back, the patient developed lesions on the nape of the neck, which extended into the scalp. Fungal scrapping performed three times earlier was negative at each visit as the lesions were slightly scaly. The anti-nuclear antibody (ANA) global test for antibodies was negative. The patient had been treated with topical steroids and oral and topical antifungals 2 years prior. Lesions used to partially subside with treatment. Examination showed a 7 cm × 8 cm non-scaly arciform erythematous plaque with central hyperpigmentation on the back [Figure 1] and a 3 × 2 cm erythematous plaque on the nape of the neck, which was extending into the scalp.

Figure 1.

Erythema annulare centrifugum on the back

A differential diagnosis of erythema annulare centrifugum (EAC), Hansen's disease, granuloma annulare, atypical mycosis fungoides, and vasculitic annulare erythema were considered. Punch biopsy was performed from the plaque on the back. Biopsy on hematoxylin and eosin stain showed an acanthotic epidermis with dense superficial and deep perivascular lymphocytic infiltration [Figure 2] and leucocytoclasis, endothelial swelling and extravasation of erythrocytes involving both superficial and deep dermal vasculatures. No fibrin deposits were seen [Figure 3]. A final diagnosis of deep variant of erythema annulare centrifugum with vasculitis (deep variant) was made and the patient was treated with topical steroids and tacrolimus. The patient had significant improvement with this treatment.

Figure 2.

H and E, stain ×5

Figure 3.

H and E, stain ×40

EAC is one of the gyrate or figurate erythemas. The term “EAC” is sometimes applied to those annular erythemas that do not fit into other gyrate erythemas. EAC is considered a hypersensitivity reaction to an unknown stimulus that can be an infection (dermatophyte, candida, molluscum, Epstein-Barr virus), an infestation (Ascaris, Borrelia, Trypanosomiasis), a carcinoma (lymphomas, leukemias), blood dyscrasias, drug sensitivity (Aldactone, Amytryptilline, Thiacetazone), dysproteinemia, or immunological disturbances.[1] Clinically, EAC presents as erythematous annular, arcuate, or polycyclic plaques. EAC is subtyped clinically and histologically into superficial and deep forms. The superficial variant has an indistinct border, being characterized by a peripheral trailing scale, whereas the deeper type is non-scaly and has a firm, indurated border.[1,2]

Histologically, traditionally, EAC is characterized by perivascular lymphocytic infiltrate of lymphocytes in a coat sleeve appearance. The superficial variant in addition is characterized by epidermal changes like focal spongiosis, focal parakeratosis, epidermal hyperplasia and papillary dermal edema. The deeper variant has an unremarkable epidermis, but there is involvement of the deeper dermal vasculature; the perivascular infiltrate is dense as well.[1,2,3,4] Standard text books of dermatology and histopathology have described these findings. Superficial lesions of EAC have also been reported to show, occasionally, histiocytes, eosinophils, endothelial cell swelling and sparse focal extravasations of erythrocytes in the papillary dermis. Rarely, vasculitis can been seen in EAC associated with malignancy.[3,4,5]

Our patient presented with persisting EAC, with the characteristic perivascular lymphocytic infiltrates. In addition, there was leucocytoclasis, endothelial swelling and extravasations of erythrocytes involving both the superficial and the deep dermal vasculature, findings that can be mistaken for vasculitis. However, symptoms at the time of biopsy were not suggestive of vasculitis. The vascular phenomenon without a known trigger cannot fully explain the persistent nature of EAC. Hence, unless a proper history and clinical features are available to the pathologist, there may be reporting errors. Biopsies taken at different times may also help in detecting these rare and infrequently reported histopathologic changes.

We report this case for this rare association of EAC with various rare histological findings.