Rapidly progressive classic Kaposi sarcoma in an adolescent: response to interferon alfa therapy and biological correlates

than 5% of patients. The commonest site is bone ⁄ bone marrow, followed by soft tissue and lymph nodes, then liver and lung. The median time to systemic metastasis is 2 years. Whether permanent shunting has an adverse effect on both the likelihood of metastasis and the time to metastasis is controversial. To our knowledge, this is the first case of systemic metastasis from medulloblastoma presenting in the skin and illustrates the need always to consider metastasis in the differential diagnosis of cutaneous nodules, however unlikely it may appear in terms of tumour biology.