Schwannomatosis is an extremely rare genetic disorder closely related to the more-common disorder neurofibromatosis (NF). Originally described in Japanese patients, it consists of multiple cutaneous schwannomas, central nervous system tumors, and other neurological complications, excluding hallmark signs of NF. The exact frequency of schwannomatosis cases is unknown, although some populations have noted frequencies as few as 1 case per 1.7 million people.Schwannomas are mostly benign tumors that commonly occur in individuals with NF2 and schwannomatosis (sometimes called neurofibromatosis type III). [Source: Wikipedia 
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