Abstract

Lymphomatoid contact dermatitis (LCD) is a rare form of noneczematous allergic contact dermatitis with atypical clinical and histopathological features. It can resemble early-stage mycosis fungoides (MF), classifying it as a pseudolymphoma. Although allergic contact dermatitis and cutaneous T-cell lymphomas are easy to diagnose in their typical clinical presentations, early disease features and atypical cases can make differentiating between benign-reactive and malignant conditions challenging. The irritant chemicals and dyes in soaps, detergents, and metals such as nickel and gold may cause LCD. A 55-year-old African-American male patient presented at our clinic with a complaint of a non-itchy rash involving the neck for over a month, which did not improve with OTC creams and ointments. Physical examination revealed a hypopigmented patch and papules with focal hyperpigmented areas on the posterior neck. Pink-scaled patches and papules involving the umbilical area were also noted. He didn’t have prominent lymphadenopathy. A biopsy with a clinical differential diagnosis of contact dermatitis and MF revealed interface dermatitis with epidermotropism. A CTCL panel was performed, and the C3 immunohistochemical stain had rare intradermal positivity. Additional sampling was recommended if concern for mycosis fungoides remains. The patient was scheduled for follow-up. Given the location, the additional rash, and the histopathological examination, we raised concern for MF as an alternative diagnosis, although the patient’s lesion of concern was clinically consistent with allergic contact dermatitis. We are presenting this case to remind dermatologists about the diagnostic challenges associated with these conditions.