Lymphomatoid papulosis: is a second lymphoma commoner among East Asians?

Summary Background. Lymphomatoid papulosis (LyP) is a low‐grade cutaneous lymphoma, which lies within the spectrum of primary cutaneous CD30‐positive lymphoproliferative disorders. Around 10–20% of LyP cases are associated with a second lymphoma. Aim. To analyse a cohort of Asian patients with LyP, diagnosed from 1987 to 2007 at the National Skin Centre (NSC), Singapore, in terms of epidemiology, treatment and association with a second lymphoma. Methods. Patients were identified through the NSC clinical and histological databases. Results. During this period, 13 patients were diagnosed with LyP based on clinicopathological criteria. The mean age at diagnosis was 41 years, the male : female ratio was 2.3 : 1, and 92% of the patients were Chinese. Recurrent papulonecrotic lesions were present for a mean of 3 years before diagnosis. Treatment of LyP comprised monotherapy (n = 4) or combination therapy (n = 9) using corticosteroids, oral antibiotics, methotrexate and/or phototherapy. Mean duration of follow‐up was 6.4 years. Eight patients (61.5%) were diagnosed with a second lymphoma, either before (n = 2), concurrently with (n = 1) or after (n = 5) the diagnosis of LyP. Mycosis fungoides (MF) was the commonest lymphoma (78%, n = 7), followed by primary cutaneous anaplastic large‐cell lymphoma (12%, n = 2). There was one death (mortality rate 7.7%), which occurred in a patient who had developed stage IIA MF after LyP, which subsequently progressed to systemic T‐cell lymphoma. Conclusions. LyP is a chronic, relapsing disease with considerable morbidity, but an overall good prognosis. A strikingly large proportion of our Asian patients (61.5%) had a second lymphoma, compared with previous studies. This emphasizes the importance of regular lifetime surveillance for associated lymphomas in all patients with LyP.