A 67 year old woman with a 10 year history of rheumatoid arthritis (RA) treated with methotrexate and prednisone, presented with a 2 year history of worsening multiple cutaneous plaques of variable appearance. Two distinct skin lesions were biopsied to reveal a composite cutaneous lymphoma, possibly caused by long term methotrexate therapy. An [18F] fluoro-2-deoxy-D-glucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) was performed to stage the malignancy, and was later repeated to evaluate response to chemotherapy, which guided subsequent management. We present the PET/CT imaging findings of this very rare iatrogenic (methotrexate induced) immunodeficiency-associated lymphoproliferative disorder.
Arthritis, Rheumatoid ; Composite Lymphoma ; Drug Therapy ; Electrons ; Female ; Humans ; Lymphoma ; Lymphoproliferative Disorders ; Methotrexate ; Positron-Emission Tomography and Computed Tomography ; Prednisone ; Skin

It is uncommon that two phenotypically different lymphomas develop in the same person, and especially in the skin. Composite lymphoma is defined as two distinctly demarcated types of non-Hodgkin's lymphoma (NHL) or its association with Hodgkin's lymphoma (HL) within a single organ or tissue. Discordant lymphoma is defined as two types of NHL or the association of HL with NHL at different anatomic sites in the same person. Sequential lymphoma and simultaneous lymphoma are defined as two different types of lymphoma that occur in the same person at different times and at the same times, respectively. We herein report on two cases of sequential composite lymphomas that were limited to the skin. A 57-year-old woman who had had been diagnosed with HL at the face had been treated with chemotherapy for 1.5 years. 6 months later, the patient revisited the dermatologic clinic of our hospital for a one-month history of erythematous nodules on her chest and upper extremities. Punch biopsy was performed and the pathologic diagnosis was mantle cell lymphoma. She refused further treatment. A 68-year old woman, who had been diagnosed as having extranodal marginal zone B cell lymphoma, had been treated with chemotherapy and radiation therapy for one year. After one year, she revisited dermatologic clinic of our hospital for a several-month history of erythematous nodules on her extremities. Punch biopsy from the lesion was performed and the pathologic diagnosis was cutaneous diffuse large B cell lymphoma, the leg type. She was scheduled for chemotherapy (rituximab with cyclophosphamide, adriamycin, vincristine and prednisolone (R-CHOP)). To the best of our knowledge, our cases are the first such cases in the Korean dermatologic literature.
Biopsy ; Composite Lymphoma ; Cyclophosphamide ; Doxorubicin ; Extremities ; Female ; Hodgkin Disease ; Humans ; Leg ; Lymphoma ; Lymphoma, B-Cell ; Lymphoma, B-Cell, Marginal Zone ; Lymphoma, Mantle-Cell ; Lymphoma, Non-Hodgkin ; Middle Aged ; Prednisolone ; Skin ; Thorax ; Upper Extremity ; Vincristine