▁of ▁cells ▁from ▁connect ive ▁t issue . ▁M ast ▁cell ▁sar com a ▁is ▁an ▁extremely ▁rare ▁tum or . ▁Only ▁ 3 ▁cases ▁are ▁reported ▁so ▁far . ▁Pro gn osis ▁is ▁extremely ▁poor . ▁People ▁with ▁a ▁m ast ▁cell ▁sar com a ▁have ▁no ▁skin ▁les ions , ▁and ▁path ology ▁exam ination ▁of ▁the ▁tum or ▁shows ▁it ▁to ▁be ▁very ▁m align ant ▁with ▁an ▁ag gress ive ▁growth ▁pattern . ▁M ast ▁cell ▁sar com a ▁should ▁not ▁be ▁confused ▁with ▁ext rac ut aneous ▁mas to cy t oma , ▁a ▁rare ▁ben ign ▁m ast ▁cell ▁tum or ▁without ▁destruct ive ▁growth . ▁In ▁the ▁cases ▁observed , ▁m ast ▁cell ▁sar com a ▁terminated ▁quickly ▁as ▁m ast ▁cell ▁le uk emia ; ▁one ▁of ▁the ▁most ▁ag gress ive ▁human ▁can cers . ▁ ▁See ▁also ▁ ▁Mas to cy t osis ▁ ▁References ▁ ▁External ▁links ▁▁ ▁Category : D erm al ▁and ▁sub cut aneous ▁growth s ▁Category : S ar com a <0x0A> </s> ▁The ▁following ▁are ▁characters ▁in ▁the ▁Oh ▁My ▁God dess ! ▁m anga ▁and ▁an ime ▁series : ▁ ▁Main ▁characters ▁ ▁Ke i ichi ▁Mor is ato ▁▁ ▁is ▁a ▁student ▁of ▁the ▁N ek omi ▁Institute ▁of ▁Technology ▁and ▁a ▁member ▁of ▁the ▁N IT ▁Motor ▁Club . ▁One ▁day ▁Ke i ichi ▁accident ally ▁d ial s ▁the ▁God dess ▁Rel ief ▁Office . ▁After ▁sum mon ing ▁Bel ld andy ▁by