Lichen striatus with syringotropism and hyperplasia of eccrine gland cells: a rare phenomenon that should not be confused with syringotropic mycosis fungoides

Cutaneous eccrine inflammation and necrosis: review of inflammatory disorders affecting the eccrine apparatus including new associations

Despite being frequently overlooked during the examination of histopathological sections, eccrine sweat glands can offer clues for diagnosing various skin conditions. They provide important functions and can lead to several diseases when inflamed or injured. This review article provides information regarding eccrine physiology as well as well-established and novel entities that occur in association with eccrine gland pathology.

Adnexotropic Variants of the Interface Dermatitides: A Review

The interface dermatitides encompass a vast array of cutaneous entities which, at times, may present with particular clinical variants with adnexal predilection. Similarly, hair follicle and eccrine gland involvement of some of these entities has been observed on histopathology. This review aims to describe the various adnexotropic presentations of the interface dermatitides. Recognizing that the adnexa can be a frequent site of involvement of these conditions may aid dermatopathologists in making the correct diagnosis and avoid misinterpreting adnexotropism for other conditions such as the great imitator, mycosis fungoides.

Syringotropic Lichen Planus: A Potential Histopathologic Mimicker of Syringotropic Mycosis Fungoides

Perieccrine inflammation may be observed in several different dermatoses, but true permeation of the secretory coil by lymphocytes (lymphocytic syringotropism) is a rather uncommon finding, usually observed in mycosis fungoides (MF-syringotropic MF). Rare cases of syringotropic lichen striatus and lymphocytic autoimmune hidradenitis showing a similar pattern have been described as well. We describe an exceptional case of lichen planus (LP) characterized by marked lymphocytic syringotropism with focal hyperplasia of the eccrine epithelium. Histopathology was characterized by the combination of features of conventional LP, prominent permeation of the secretory portion of the eccrine glands by reactive lymphocytes, and focal involvement of a hair follicle. Syringotropic LP may be regarded as a histologic mimicker of syringotropic MF, thus representing a potential diagnostic pitfall.

[Lichen nitidus and lichen striatus]

Lichen nitidus is a rare, chronic dermatosis which occurs more often in children than in adults. It presents with tiny, monomorphous, lichenoid, mostly asymptomatic papules in regional or disseminated distribution which show a pathognomonic histological pattern. The pathogenesis is unclear; however, immunologic phenomena and genetic factors are under discussion. In rare cases, an association with other dermatoses and systemic diseases has been described. Moreover, medical treatments have been incriminated as triggers. Considering the self-limited course in mostly young patients, treatment must be thoroughly weighed. Possible therapeutic options include topical corticosteroids and calcineurin inhibitors as well as oral antihistamines, corticosteroids and narrow-band ultraviolet B phototherapy. Lichen striatus is an acquired, usually asymptomatic dermatosis occurring mostly in preschool children. The characteristic feature is the arrangement of small, flat, light red- to skin-colored papules along the lines of Blaschko. Therefore, a postzygotic mutation of epidermal progenitor cells induced to express new surface antigens by trigger factors as infections, vaccinations or trauma with consecutive immune reaction is assumed. Nail involvement of the affected limb can rarely occur. Lichen striatus usually heals without scarring within several months, so that therapies with severe side effects are obsolete. Mild topical corticosteroids or calcineurin inhibitors may be used, especially if patients exceptionally suffer from pruritus. A postinflammatory hypopigmentation can persist for months to years.