Introduction

The diagnosis of cutaneous lymphomas is extremely difficult because of their morphological diversity and clinical similarity to many dermatoses.

Objective

Presentation of the case of a 70-year-old woman diagnosed with lichen sclerosus in whom the evolution of skin lesions raised suspicions of lymphocytic hyperplasia.

Case report

The patient diagnosed with lichen sclerosus was hospitalized three times due to exacerbation of skin lesions with accompanying mycosis fungoides-mimicking infiltration. Cutaneous lymphoma was excluded in biopsy specimens collected from skin lesions. In the following months, a new nodular lesion appeared on the patient’s face that turned out to be marginal zone lymphoma. After increasing the dose of methotrexate to 20 mg/week, a rapid remission of skin lesions was achieved.

Conclusions

The presented case shows that the diagnosis of primary cutaneous lymphoma is a significant challenge in everyday dermatological practice and requires repeated biopsy.