Arabic

šāmat- - mole; sign (any black sign seen on earth) (BK 1 1300)

PS
*ŝₓV̄m-at- - birth-mark, mole

An entangled and highly hypothetic case likely complicated by contamination of two roots, close phonetically and semantically. In the anatomic term, a hypothetic *ŝx is tentatively postulated as a first radical based on Hbr. pB. š-­ and Arb. š-­.