A 60-year-old Japanese woman presented with a blue macule associated with a black dome-shaped nodule and a red flat nodule on the right occiput. Histopathological examination of the red nodule revealed large atypical cells containing no melanin proliferated in the entire dermis and the subcutaneous tissue. Immunohistochemical samples were positive for HMB-45 and Melan-A. In contrast, in the black nodule, tumor cells containing abundant melanin granules densely proliferated throughout the entire dermis without atypia. We diagnosed a malignant blue nevus with an amelanotic region occurring on the cellular blue nevus. The patient died from lung and bone metastases 2 years after surgery.
Autoimmune progesterone dermatitis (APD) is a rare hypersensitivity reaction to endogenous progesterone and/or synthetic progestins with multiple clinical manifestations, including erythema, eczema, urticaria, asthma, and anaphylaxis. Although the pathogenesis of APD is poorly understood, protocols for medical management are required particularly for patients interested in fertility and conception. Recently, desensitization has attracted attention. We describe a 25-year-old woman with erythematous plaque and blistering on the distal extremities, which recurred a few days before her menstrual cycle. She was diagnosed with APD by intradermal test. Her symptoms were controlled after prescribing low-dose estrogen-progestin instead of dienogest. The results suggested that low-dose estrogen-progestin may be an effective treatment for APD.