Mycosis fungoides presenting at the site of a transdermal estradiol patch

Abstract

To the Editor: A 44-year-old Caucasian woman presented with a chronic isolated plaque on her left buttock. Nine years ago, upon removing an estradiol-containing birth control patch, the patient noticed a red rash distinctly localized to the application site. Of note, the patient placed a similar contraceptive patch on her contralateral buttock 1 month before the development of her rash, without sequelae. She immediately discontinued use of the estradiol patch. Over the next several years, the red patch developed more scale, but remained asymptomatic and stable in size. Although no early images are available, the patient’s husband is an internist and corroborated the initial development and subsequent evolution of her rash. Two years ago, she was unsuccessfully treated with a 1-week course of mid-potency topical steroids for presumed nummular eczema. The chronicity of the lesion ultimately prompted punch biopsy. The pathology revealed a CD4+ atypical lymphoid proliferation with marked epidermotropism and loss of CD7 and CD62L unequivocally diagnostic of plaque-stage mycosis fungoides (MF) (Fig 1). She presented to our clinic for subsequent workup and treatment. At that time, she denied any other areas of skin involvement and was otherwise healthy. On examination, she had a single, well-demarcated, 5- × 4-cm erythematous scaly plaque on the left buttock at the application site of her contraceptive patch 9 years before presentation (Fig 2). Given the stability of her limited disease, and absence of other symptoms, imaging and patch testing were deferred. She was treated with a 12-week regimen of twice-daily application of superpotent topical steroids alternating every 2 weeks with mid-potency topical steroids with significant improvement.