There are two subtypes of hydatidiform mole: complete hydatidiform mole, and partial hydatidiform mole. The four malignant tumours
Invasive mole
Choriocarcinoma
Placental site trophoblastic tumour
Epithelioid trophoblastic tumourAll five closely related tumours develop in the placenta. All five tumours arise from trophoblast cells that form the outer layer of the blastocyst in the early development of the fetus. In a normal pregnancy, trophoblasts aid the implantation of the fertilised egg into the uterine wall. But in GTD, they develop into tumour cells. Cause
Two main risk factors increase the likelihood for the development of GTD: 1) The woman being under 20 years of age, or over 35 years of age, and 2) previous GTD. Although molar pregnancies affect women of all ages, women under 16 and over 45 years of age have an increased risk of developing a molar pregnancy. Being from Asia/of Asian ethnicity is an important risk factor.Hydatidiform moles are abnormal conceptions with excessive placental development. Conception takes place, but placental tissue grows very fast, rather than supporting the growth of a fetus.Complete hydatidiform moles have no fetal tissue and no maternal DNA, as a result of a maternal ovum with no functional DNA. Most commonly, a single spermatozoon duplicates and fertilises an empty ovum. Less commonly, two separate spermatozoa fertilise an empty ovum (dispermic fertilisation). Partial hydatidiform moles have a fetus or fetal cells. They are triploid in origin, containing one set of maternal haploid genes and two sets of paternal haploid genes. They almost always occur following dispermic fertilisation of a normal ovum.
Nummular dermatitis is one of the many forms of dermatitis. it is characterized by round or oval-shaped itchy lesions. The name comes from the Latin word "nummus," which means "coin." Signs and symptoms
Nummular dermatitis is characterized by chronic or relapsing itchy coin-sized ovoid-shaped red plaques. They can occur on the trunk, limbs, face, and hands. Causes
Many contact sensitizers or irritants are known to cause contact dermatitis superimposed on nummular dermatitis. Studies have implicated nickel, cobalt, chromate, and fragrance as likely culprits. Xerosis, or dehydration of skin is also a likely cause. Infection with Staphylococcus aureus bacteria or Candida albicans may also play a role. Diagnosis
Diagnosis of nummular dermatitis is largely via clinical observation. Biopsies are typically not necessary, and cannot be used to rule out other atopic dermatitis or other eczemas. However, patch testing may be employed to rule out irritants (contact dermatitis) as a cause. In children, nummular dermatitis is commonly confused with tinea corporis. Treatment
One of the keys to treatment and prevention involves keeping the skin moisturized. Lotions, creams, and bath oils may help prevent an outbreak. If the condition flares up, a common treatment involves the application of topical corticosteroids. Oral antihistamines may help lessen itching. Avoidance of irritants is a common strategy. More severe cases sometimes respond to ultraviolet light treatment. If the condition occurs only during the sun-less winter months then vitamin D supplement might be an effective treatment. Epidemiology
The prevalence of nummular dermatitis in the United States is approximately 2 per 1,000.