Supplementary Material for: Brain Metastasis in Nasopharyngeal Carcinoma: A Case Report

Nasopharyngeal Carcinoma (NPC) is endemic in South East Asia. Despite the close proximity of the nasopharynx to the brain, true brain metastasis is rarely observed in NPC. We present an interesting case of NPC with brain metastasis which to our knowledge is the first case reported in South East Asia. Patient was asymptomatic and brain metastasis was detected during surveillance PET scan. He underwent craniectomy and excision of brain metastasis followed by Gamma Knife to the tumour cavity and remain well two years post resection. We explore several possible hypotheses for the rarity of this phenomena with the aid of seed and soil theory including a new concept of (i) organ negative trophism (ii) effective and good local regional control, (iii) the inability of NPC to penetrate the BBB and overcome brain immune microenvironment.