An Atlas of Lumps and Bumps, Part 45: Steatocystoma Multiplex
Steatocystoma Multiplex
Steatocystoma multiplex is a hamartomatous malformation of the pilosebaceous glands characterized by multiple skin-colored sebum-containing dermal cystic papules and nodules.1-3 The condition frequently presents in adolescence and early adulthood.3-6 Occasionally, it can appear earlier only to worsen at puberty, when the activity of the sebaceous glands is elevated.4 Steatocystoma multiplex has been described at birth and in patients in their eighth decade.2,3,7 There is no sex predilection.2,6,8
Steatocystoma multiplex is a rare skin condition; the exact incidence is not known. Familial cases are often caused by mutations in exon 1 of the keratin 17 (KRT17) gene located on chromosome 17q21.2 and have an autosomal dominant mode of inheritance.9-12 The majority of cases are sporadic.8,13,14 Androgenic stimulation of the sebaceous glands, genetic predisposition, along with environmental factors influence the onset of steatocystoma multiplex. The condition has been reported following the use of ustekinumab which might have unmasked a genetic predisposition.15 Hypertrophic lichen planus, eruptive vellus hair cysts, pachyonychia congenita type 2 (Jackson-Lawler syndrome), hypohidrosis, congenital alopecia, acrokeratosis verruciformis, hidradenitis suppurativa, hypothyroidism, preauricular sinuses, and natal teeth occur with increased frequently in patients with steatocystoma multiplex.5,16-19
Clinically, steatocystoma multiplex is characterized by multiple, asymptomatic, smooth, round, soft to firm, often freely movable, yellow to skin-colored papules and nodules (Figure 1).1,7,8
Figure 1. Steatocystoma multiplex is characterized by multiple, asymptomatic, smooth, round, soft to firm, often freely movable, yellow, skin-colored papules and nodules.
Lesions tend to be a few millimeters to a centimeter in diameter and are slow growing.1 Superficial lesions are usually yellowish while deeper lesions skin-colored (Figure 2).1,8 The overlying epidermis is normal with no central punctum present. 1,8,20 The content is usually oily or creamy. Sites of predilection include the trunk (especially the presternal area), neck, axillae, proximal extremities, and groin where high numbers of sebaceous glands are found.1,4,7,21