22.1 Trichofolliculoma (see Fig. 22.1A–E ) Uncommon solitary papule on the face (1.44), sometimes with a plugged orifice in which vellus hairs are seen. ■ Large open or closed comedo-like lesion (sometimes resembling a cyst if there is no orifice)…
21.1 Sebaceous hyperplasia (see Fig. 21.1 ) Common whitish (1.150) to yellowish (1.151) papules, often with a rolled edge or central umbilication, most common on the face (1.145). ■ Enlarged, otherwise normal sebaceous gland, often with a large central orifice…
20.1 Freckle (ephelis, plural is ephelides) Very common multiple red – brown macules (1.18) on face (1.44) and shoulders, often genetically inherited in fair-skinned patients , especially those with red hair. Lesions darken easily with sun exposure. ■ Increased melanin…
A cyst is a walled-off cavity filled with keratin, mucin, or fluid, and a list of cystic lesions other than those in this chapter appears in Section 1.25. Most true cysts have an epithelial lining, but some, such as the…
18.1 Epidermal nevus (linear epidermal nevus) (see Fig. 18.1A,B ) Somewhat common, linear , warty plaque , usually on the extremities, sometimes on trunk, since birth or early childhood, persists indefinitely. Sometimes lesions are more subtle, more macular, or they…
17.1 Acrodermatitis enteropathica Rare autosomal recessive disorder due to a defect in zinc absorption (mutation in intestinal zinc-specific transporter SCL39A4). Decreased zinc levels can be documented in the serum. Infants develop perioral (1.82), groin (1.55), perianal (1.108), scalp (1.124), and…
Panniculitis is inflammation in the subcutaneous fat. The classification of panniculitis is unsatisfactory, as there is considerable overlap between the clinical and histologic features of these diseases. Although many authors categorize a panniculitis as a “septal” panniculitis if it involves…
This chapter covers most of the more important parasites, or those with more specific pathologic findings in the skin. Many others are omitted because they either mostly involve deeper tissue, they produce nonspecific findings in the skin unless the parasite…
14.1 Human papillomavirus infection (HPV, viral wart, verruca) (see Fig. 14.1A–H ) Verrucous papules (1.146) due to infection with HPV, of which there are more than 60 subtypes. Warts often bend the dermatoglyphic lines and may have black dots representing…
13.1 Dermatophytosis (tinea) (see Fig. 13.1A–G ) Very common superficial cutaneous infection by one of the three genera: Microsporum , Epidermophyton , and Trichophyton . Scaly, erythematous plaques, often annular (1.5, hence sometimes called “ringworm”), sometimes pustular, rarely vesicular (1.147).…