DermaDiagnosis

A Roundabout Journey to Diagnosis

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Cheek lesion

After journeying for several months from Honduras, this 30-year-old woman visits the clinic for evaluation of a lesion that has been growing on her cheek since before she started traveling. She saw several providers—mostly in NGO clinics—along her journey. The diagnosis they gave was consistently “ringworm.” She was offered various topical creams, none of which produced any results.

Though the lesion is not painful, it causes some itching. The patient is much more concerned about its appearance. Through interpreters, she claims to be in otherwise good health. She has no other lesions, joint pain, fever, or malaise. She reports neither her family nor fellow travelers have such lesions.

Examination reveals an impressive 3-cm, round, papulosquamous plaque on the right side of her face (below the malar area). The lesion is neither tender nor notably warm. There are no palpable lymph nodes in the area. The scaling is mostly on the periphery. A KOH prep of the scaling shows no fungal elements.

The differential for this lesion includes which of the following?

Psoriasis

Leishmaniasis

Squamous cell carcinoma

Discoid lupus erythematosus

All the above

ANSWER

The correct answer is all the above (choice “e”).

DISCUSSION

The differential for round or annular, scaly lesions is lengthy. In addition to all 4 conditions listed above, it includes eczema, basal cell carcinoma, and irritant or contact dermatitis.

With this patient’s history, the diagnosis of fungal infection was not unreasonable. However, the total lack of response to antifungal treatment—along with a negative KOH prep—made that diagnosis questionable at best. Then there was the lack of lymphadenopathy, which would almost certainly have been present with such longstanding infection. Given her country of origin, cutaneous New World leishmaniasis (caused by a protozoan delivered to the patient by an insect vector) was a possibility.

For this patient, skin biopsy with a 4-mm punch was the only way to establish the correct diagnosis. The defect from the biopsy was closed with 5-0 nylon sutures to minimize scarring.

The pathological findings included interface dermatitis, apoptotic keratinocytes, and a brisk periadnexal lymphocytic infiltrate, which—given the morphological and historical context—were entirely consistent with discoid lupus erythematosus (DLE; otherwise known as subacute cutaneous lupus erythematosus). Subsequent bloodwork failed to show any connection with systemic lupus erythematosus (SLE), which is not surprising because only about 18% of DLE cases evolve into SLE.

DLE is more common in women, especially in those with skin of color. The associated lesions are seldom as impressive as this patient’s, manifesting as papulosquamous patches typically found on the ears, neck, face, arms, and other sun-exposed areas. Indeed, it appears that sun exposure is a major trigger for the disease—a clue that can assist with the diagnosis.

TREATMENT

In addition to proscribing excessive sun exposure, providers should encourage the use of sunscreen. DLE is often treated with topical steroids. More advanced cases, such as this patient’s, may require oral hydroxychloroquine (200 mg bid). Though these treatments are effective in most cases, DLE can leave serious scarring and/or discoloration, especially in those with darker skin.

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