Adult onset folliculocentric langerhans cell histiocytosis confined to the scalp.

Langerhans cell histiocytosis (LCH) is a pleomorphic disease entity characterized by local or disseminated atypical Langerhans cells found most commonly in bone, lungs, mucocutaneous structures, and endocrine organs. Cutaneous disease occurs in approximately one quarter of all cases. Cutaneous findings include soft-tissue swelling, eczematous changes, a seborrheic dermatitis-like appearance, and ulceration. We report a rare case of LCH confined to the scalp with folliculocentric infiltrates. This 32-year-old male patient presented with follicularly based erythema, scale, and pustules unresponsive to topicals and oral antibiotics. The patient's lesions mimicked lichen planopilaris and folliculitis decalvans during the disease process. On hematoxylin and eosin stain, scalp biopsy showed a perivascular interstitial patchy lichenoid mononuclear cell infiltrate that focally abutted follicular infundibula. Prominent mononuclear cells having reniform nuclei were present, and immunoperoxidase stains for CD1a confirmed Langerhans cell differentiation. Serological and imaging workup failed to display systemic involvement.

Granular parakeratosis: a case report and literature review.

BACKGROUND: Granular parakeratosis is suspected to result from an error in epidermal differentiation, leading to variably pruritic, hyperpigmented-to-erythematous patches and plaques. Characteristic histopathologic features include a thickened stratum corneum, compact parakeratosis with retention of keratohyalin granules, vascular proliferation, and ectasia. The pathogenesis of this entity is uncertain. METHODS: We present a case of axillary granular parakeratosis and review the literature. RESULTS: The lesion showed a thickened stratum corneum with compact parakeratosis, slight epidermal hyperplasia, and a sparse perivascular lymphohistiocytic infiltrate. Keratohyalin granules were diffusely present within the parakeratotic stratum corneum, and the retained granular layer showed focal vacuolization. CONCLUSIONS: Granular parakeratosis is a rare form of parakeratosis most often seen in the axilla, although other intertriginous areas may be affected. Unique histopathologic findings allow for a specific diagnosis to be made. Although an irritant contact reaction appears causative, mechanical irritation may also play a role in inducing these skin changes.

Primary cutaneous ganglioneuroma: a report of two cases and literature review.

Primary cutaneous ganglioneuroma is a rare neoplasm first described by Collins et al. in 1972. Eight cases have been reported in the English literature to date. We report two cases of solitary cutaneous ganglioneuroma, one constituting, to our knowledge, the first reported case of this entity occurring on the face. Clinically, both lesions were firm flesh-colored papules and asymptomatic, being removed primarily for cosmesis. Neither patient had any significant past medical history. Histologically, both neoplasms consisted of relatively well-circumscribed spindle cell proliferations of axons and Schwann cells with interspersed mature ganglion cells. There was also focal myxoid change. The spindle cell component stained positively for S-100 protein, and the ganglion cells stained positively for glial fibrillary acidic protein and neurofilaments by routine immunohistochemistry.