Vulvar sebaceous hyperplasia associated with lymphedema of external genitalia

Sebaceous glands are present throughout the skin, except on palms and soles. Sebaceous glands are well developed until a few weeks after birth, probably because of maternal hormones. They almost disappear during early childhood, especially within the first few months. As a direct result of increased androgen output, sebaceous glands enlarge during puberty, and then remain stable until middle age, later tending to decrease slowly after menopause. Sebaceous gland hyperplasia (SGH) is a condition occurring most commonly on the forehead and cheeks, but occasionally affecting the areola, chest, or genital skin; sometimes it is clinically mistaken for basal cell carcinoma. Although termed hyperplasia, some authors concluded that this condition is a benign neoplasm, rather than hyperplasia, because these lesions do not undergo clinical involution. Other authors, instead, defined this lesion as a benign hamartomatous condition of epidermal appendage tumors with sebaceous differentiation, a definition that is now universally accepted. Sebaceous gland hyperplasia is reported in association with underlying mesenchymal proliferation, such as dermatofibroma, neurofibroma, melanocytic nevus, and acrochordon. Moreover, it has been described in association with benign lentiginosis and in patients treated with cyclosporine. Many factors are assumed to be involved in the pathogenesis of SGH, which, as of today, is not fully understood: prolonged ultraviolet radiation, previous surgery, and chronic inflammation have been claimed to be some pathogenic factors. Regarding chronic inflammation, after a critical review of the paper of Prayson et al., we were not able to find any strict correlation between SGH and surgery and chronic inflammation: SGH was not mentioned at all, while nodular hyperplasia of minor vestibular glands was associated with previous surgical manipulation or chronic inflammatory infiltrate. Clinically, SGH features one or, more commonly, multiple, elevated, small, soft, slightly umbilicated papules, often yellow in color. Differential diagnosis includes several tumors with sebaceous differentiation such as nevus sebaceous, sebaceous epithelioma, follicule sebaceous cystic hamartoma, sebaceous adenoma, and trichofolliculoma. Microscopically, SGH is generally characterized by a single enlarged sebaceous gland composed of numerous fully, or nearly full, mature sebaceous lobules, grouped around a centrally located and wide sebaceous duct. In focally sebaceous lobules, a peripheral row composed of 70