Originally: the cutaneous manifestation of neurofibromatosis (von Recklinghausen's disease), consisting of numerous fleshy, often pedunculated, papules and nodules (now historical). Later also (chiefly with distinguishing scientific Latin word): any of several disorders characterized by similar skin lesions. Also: an individual lesion of any of these disorders; (now usually) a skin tag (acrochordon).
Mid 19th century; earliest use found in Charles Fagge (1838–1883), physician. From scientific Latin molluscum fibrosum from post-classical Latin molluscum + post-classical Latin fibrosum, neuter of fibrosus.