Mycosis fungoides – a retrospective study of 40 cases in Hong Kong

Background Mycosis fungoides is rare in Hong Kong and oriental data on the disease are lacking. Methods This is a multiclinic, 13‐year, retrospective study to determine the clinicopathologic characteristics, treatment, and disease outcomes of 40 patients with mycosis fungoides/Sézary syndrome seen in the Social Hygiene Service, Hong Kong. Results There were 27 males and 13 females with a mean age at diagnosis of 56.4 years. Based on figures in the Social Hygiene Service alone, the incidence in Hong Kong was estimated to be 0.044 per 100,000. Eighty‐five per cent of patients presented with skin‐limited disease, and pruritus was absent in 40% of patients. A mean of 1.48 biopsies was needed to establish the diagnosis, and only 58% of the mycosis fungoides skin biopsies were reported to be histologically diagnostic of the disease. Atypical lymphocytes, epidermotropism, interface changes, and Pautrier's microabscesses were the four most frequently encountered features that attained statistical significance. Sixty‐nine per cent of patients were treated with psoralen–UVA as their initial therapy, and the complete response and relapse rates were 78.3% and 66.6%, respectively. Disease progression to more advanced stages was only seen in 15% of patients. The 5‐year survival rates for the whole group and for stage IA and IB patients were 88.8% and 100%, respectively. Conclusion Mycosis fungoides is rare amongst Hong Kong Chinese and the majority present with skin‐limited nonprogressive disease.