Lymphatic Malformation Key Points Lymphatic malformations (LM) are benign developmental vascular channels lined by endothelial cells and composed of anomalous, usually dilated, lymphatic channels and spaces The pathogenesis of LM…

Lupus Erythematosus Key Points Lupus erythematosus (LE) is a multisystem, chronic autoimmune disease with a wide spectrum of presenting symptoms Cutaneous manifestations appear in 72% to 85% of patients with…

Lipoma Key Points Lipomas are the most common benign soft-tissue mesenchymal tumors They are classified into subtypes depending on the types of tissues, including simple, spindle cell lipoma, hibernoma, pleomorphic…

Lipoid Proteinosis Key Points Lipoid proteinosis is a rare autosomal recessive dermatosis that presents with dermatological, ophthalmological, otolaryngological, and neurological manifestations It is a multisystem disease due to multiple mutations…

Lipoblastoma and Lipoblastomatosis Key Points Lipoblastoma and lipoblastomatosis are rare, benign, soft-tissue tumors of embryonal fat occurring primarily in children Lipoblastoma refers to a circumscribed encapsulated form, and lipoblastomatosis refers…

Leiomyoma Key Points Leiomyoma is a benign soft-tissue neoplasm arising from smooth muscle Cutaneous leiomyomas are divided into three subtypes: piloleiomyomas originate from the attachment points of the arrector pili…

Keratinous Cyst, Intratarsal Key Points Intratarsal keratinous cysts arise from the meibomian glands of the tarsal plates They do not arise from the dermis, and therefore are distinct from epidermoid…

Keratinous Cysts, Cutaneous Key Points Cutaneous keratinous cysts are derived from the folliculose-baceous apparatus, with different epithelial segments giving rise to distinct histologically defined types of cyst Keratinous cysts arising…

Keratoacanthoma Key Points Keratoacanthoma is a common tumor It is seen most frequently in fair-skinned individuals with a predilection for sun-damaged skin Keratoacanthoma can be solitary or multiple Solitary KA…

Inverted Follicular Keratosis Key Points Inverted follicular keratosis (IFK) is a rare benign epithelial tumor It originates from the infundibular portion of the hair follicle Ninety percent of IFK cases…