[Multiple terminal hair cysts in perianal region].

cyst wall, the type of keratinization, the presence of vellus or terminal hair shafts, and the relationship with adjacent skin appendages. 6 The most common cutaneous cysts are those originating in the pilosebaceous unit, with infundibular or epidermoid cysts and trichilemmal cysts being the most common. Hair shafts inside cutaneous cystic lesions are a rare finding, and terminal hair shafts in infundibular cysts are rarer still. 7 Hair shafts can be observed in dermoid cysts, hybrid cysts, 7 steatocystomas/eruptive vellus cysts, 8 comedones, and pigmented follicular cysts. Terminal hair cysts are more common in men and present as single grayish, brown, blackish, or bluish lesions measuring 0.4 to 1.5 cm. 1,9 These cysts are located on the head and neck and less often, on the axillae, abdomen, pubis, vulva, and legs. 1,5 Histopathologically, they are characterized by the presence of terminal hair shafts and epidermoid keratinization. Other cutaneous cysts, such as eruptive vellus cysts, hybrid cysts, apocrine hidrocystoma, and " pigmented epidermal cysts, " can also present clinical hyperpigmentation. Terminal hair cysts are probably underdiagnosed or, on occasions, confused with other cutaneous lesions with a similar clinical appearance (nevocellular nevi, hidrocystomas, histiocytomas, granulomas, epithelial cysts, blue nevi, etc). We believe that cutaneous cystic lesions represent a dynamic clinical and histopathological continuum and that terminal hair cysts should be considered as a separate entity within that continuum for the time being. Cutaneous cysts should not be classified as static entities, because the increasingly numerous descriptions of hybrid cysts 7,10 have merely shown that overlapping histological findings for the various types of cutaneous cystic lesions are far from unusual. 1 described a rare variant of infundibular cyst they called a " pigmented follicular cyst, " characterized histopathologically by a wall with epidermoid keratinization and numerous thick, internally pigmented hair shafts. In 1990 Ribera et al 2 described the multiple variant of this type of cyst. The solitary variant has been reported in a few cases, 3 but the multiple variant is rare. 4,5 We describe a 63-year-old man with no relevant history who consulted for asymptomatic perianal lesions from 1 year earlier. The number and size of the lesions had remained stable since onset. No topical treatments had been applied, and no rubbing or trauma had occurred in the area. The perianal region presented several yellowish, raised, circumscribed lesions of 1 to 3 mm in diameter with a smooth surface (Figure 1). …