[Clinical presentation of cutaneous adnexal tumors]

Cutaneous adnexal lesions can sometimes be clinically diagnosed even by an experienced clinician or a differential diagnosis can at least be narrowed down. However, clinical findings alone cannot replace histological investigations and diagnosis or make them superfluous. This expertise is based on an algorithm which first differentiates inflammatory pseudo-tumors, such as ruptured infundibular cysts (atheroma) from authentic neoplastic adnexal lesions. In a second step criteria of regularity and/or chaos, such as asymmetry, irregular border, color variation and/or destruction with exulceration help to evaluate the dignity. In a third step criteria of differentiation allow the characterization of lesions varying in size from macules to papules, plaques, nodules and tumors to the subgroups of adnexal differentiation. Infundibular differentiation is characterized by comedones and is skin-colored, yellow or white and hard. Follicular differentiation notifies hair and is skin-colored, pearl-like to occasionally brown-black and variably hard. Sebaceous differentiation signifies lobulation and is yellow to skin-colored or red and soft. Apocrine lesions are reddish and fleshy. Eccrine differentiation shows either papillary reddish-brown (differential diagnosis viral warts) or skin-colored hard lesions. Multiple, monomorphous lesions are characteristic of syndromes, such as Spiegler-Brooke-Fend, Birt-Hogg-Dubé, Muir-Torre, and Gorlin-Goltz.One peculiarity of adnexal lesions is their potential to form cysts. Cysts with horny or hairy material are skin-colored to yellow, with glandular fluid fluctuation, a bluish character, and with illumination a Tyndall phenomenon becomes obvious, while ruptured cysts reveal an erythematous-reddish, ill-defined foreign body reaction. Brown to bluish-gray and black color is seen by the presence of melanocytes with melanin in lesions with mostly follicular differentiation. Strong vascularization and bleeding are reddish, soft, spongy and compressible and in due course variably dark due to the presence of hemosiderin.