What characterizes a Partial Hydatidiform mole?

A Partial Hydatidiform mole is characterized primarily by the fertilization of an ovum by two or more spermatozoa, resulting in abnormal genetic material. Typically, a partial mole presents with a triploid set of chromosomes (69 XXX, 69 XXY, or 69 XYY), which usually arises from the fertilization of a normal egg by two sperm. This condition leads to some fetal tissue being present, but the accompanying placental tissue becomes abnormal.

The other options do not accurately describe the characteristics of a Partial Hydatidiform mole. While "no embryo" refers to a complete Hydatidiform mole, which is characterized by loss of all embryonic structures, the presence of fetal tissue in a partial mole differentiates it from a complete mole. The option mentioning "46 XX parental derivation" does not apply since a Partial Hydatidiform mole has triploidy, and the "well-circumscribed and painless breast mass" pertains more to breast pathology rather than obstetric pathology, making it irrelevant in this context. Thus, the key aspect of fertilization by multiple sperm in a Partial Hydatidiform mole is what defines its pathophysiology.