An updated review of the sebaceous gland and its role in health and diseases Part 2: Pathophysiological clinical disorders of sebaceous glands

Abstract Sebaceous glands are sebum‐secreting components of pilosebaceous units. In the second of this two‐part series, we review the pathologies in which sebaceous glands are primarily and secondarily implicated. They are primarily involved in steatocystoma simplex and multiplex, sebaceous gland hyperplasia, sebaceoma, sebaceous adenoma, sebaceous carcinoma, nevus sebaceus, and folliculosebaceous cystic hamartoma. Sebaceous glands are secondarily involved in acne vulgaris, seborrheic dermatitis, and androgenic alopecia. Steatocystoma multiplex is a benign congenital anomaly presenting as yellow cysts primarily on the upper body. Sebaceous gland hyperplasia is characterized by yellow, telangiectatic papules with a central dell, and it can be treated with topical retinoids or surgical excision. Sebaceoma clinically presents on the head and neck region as a skin‐colored nodule and can be distinguished by immunohistochemistry. Stains used in the diagnosis of sebaceous adenoma and carcinoma include epithelial membrane antigen and adipophilin immunoperoxidase. Surgical excision is the preferred treatment for sebaceoma, sebaceous adenoma, and sebaceous carcinoma. Excision is not always indicated for nevus sebaceus. Folliculosebaceous cystic hamartoma is a relatively rare condition exhibiting both epithelial and mesenchymal components. Patients with acne vulgaris commonly present with papules of closed and open comedones displaying hypercornification. Seborrheic dermatitis presents as sharply demarcated yellow or red patches or plaques; antifungal agents, corticosteroids, and combination antifungal/anti‐inflammatory therapies are common treatment modalities. As a result of hair follicle miniaturization, females with androgenic alopecia present with diffuse hair thinning, while men tend to present with balding and hairline recession.