Rare Presentation of a Rare Cutaneous Neoplasm: Nonacral Sclerosing Perineuroma.

Sclerosing perineuromas are rare, benign peripheral nerve sheath tumors classically reported on the fingers and palms of young men. We present the case of a 12-year-old boy with a slow-growing nodule on his right knee. Excision was performed, and pathology was consistent with a sclerosing perineuroma. This case highlights an atypical presentation of a rare lesion and provides useful knowledge of the clinical scenarios in which sclerosing perineuromas should be included in a differential diagnosis.

Toll-Like Receptor 2 and Its Relationship With Streptococcus in Psoriasis.

The authors present the immunopathologic findings of Toll-like receptor 2 in psoriasis. This novel work shows positive staining within the dermal capillaries in psoriatic lesions. Neither normal skin nor lesional skin in eczema showed similar staining. The authors postulate how the activation of this innate immune system reactant plays a significant role in psoriasis and show how it may be associated with a cascade of events that begins with streptococcus and ends with psoriasis.

The presence and impact of biofilm-producing staphylococci in atopic dermatitis.

IMPORTANCE: Atopic dermatitis (AD) is thought to be a double-hit phenomenon with an unknown environmental component and a genetic abnormality likely centered on the filaggrin gene. Biologically, the presence of Staphylococcus aureus in AD was reported more than 2 decades ago, but the relationship to AD has been elusive. OBJECTIVE: To explore the bacteria that produce the biofilms in the lesions of AD and the response of the innate immune system to these biofilm occlusions of the sweat ducts by specifically evaluating Toll-like receptor 2. DESIGN, SETTING, AND PARTICIPANTS: University hospital dermatologic clinic study involving the environmental component related to the characterization, correlation, and impact of staphylococci and their biofilms in AD. We processed routine skin swabs from lesional and nonlesional skin from 40 patients with AD and performed scrapings and biopsies. We also obtained 20 samples from controls (10 inflamed skin samples and 10 normal skin samples). EXPOSURES: Gram staining, bright-field microscopy, hematoxylin and eosin, periodic acid-Schiff, Congo red, and light microscopy. MAIN OUTCOMES AND MEASURES: Association of staphylococcal biofilms with AD pathogenesis. RESULTS: All AD-affected samples contained multidrug-resistant staphylococci, with S aureus (42.0%) and Staphylococcus epidermidis (20.0%) as the predominant species. All isolates were positive for extracellular polysaccharide and biofilm (85.0% strong biofilm producers and 15.0% moderately to weakly positive). Polymerase chain reaction revealed the biofilm-mediating icaD (93.0%) and aap (12.5%) genes in the isolates (some contained both). We also examined tissues for microbial identification, extracellular biomass formation, biofilm formation, and staphylococcal biofilm in skin tissues. Occlusion of sweat ducts with periodic acid-Schiff-positive and Congo red-positive material was noted on microscopic tissue examination. Toll-like receptor 2 was shown to be activated in AD lesional skin (immediately proximal to the sweat ducts), which likely led to the initiation of proteinase-activated receptor 2-mediated pruritus and MyD88-mediated spongiosis. CONCLUSIONS AND RELEVANCE: Biofilm formation by AD-associated staphylococci almost certainly plays a major role in the occlusion of sweat ducts and leads to inflammation and pruritus. We believe the environmental hit in AD relates to staphylococci and their biofilms, which occlude sweat ducts.

Futcher lines: a case report in pregnancy and literature review.

Pigmentary demarcation lines are common, especially in individuals with darker skin types. Type B pigmentary demarcation lines (Futcher lines) involve the posterior lower extremities and can be associated with pregnancy, often with spontaneous resolution after delivery. The pathogenesis of pigmentary demarcation lines remains unknown; however, neurogenic inflammation and/or mosaicism are thought to play a role in their development. We report a case of type B pigmentary demarcation lines in pregnancy and provide a review of the literature.

Coma blisters sans coma.

Coma blisters (CBs) are self-limited lesions that occur in regions of pressure during unconscious states classically induced by barbiturates. We report a case of CBs sans coma that were histologically confirmed in a 41-year-old woman who developed multiple tense abdominal bullae with surrounding erythema following a transatlantic flight. Interestingly, the patient was fully conscious and denied medication use or history of medical conditions. A clinical diagnosis of CBs was confirmed by histopathologic findings of eccrine gland necrosis, a hallmark of these bulIous lesions.

Polymorphous light eruption in African Americans: pinpoint papular variant.

BACKGROUND: Polymorphous light eruption (PMLE) is the most common chronic idiopathic photodermatosis usually manifesting as a papular eruption (3-6 mm), with several other morphological variants described. METHODS: Between June 1998 and August 2001, nine patients presented with complaints of a pruritic pinpoint papular eruption associated with sun exposure. A detailed history and complete skin examination were performed along with a skin biopsy if active lesions were present. Phototesting to ultraviolet-A (UV-A), ultraviolet-B (UV-B) and visible light was performed in four patients. Antinuclear antibody (ANA) testing was performed in three patients. The diagnosis of PMLE was made based on the history, morphology of the lesions, results of phototesting and skin biopsy if available. RESULTS: In all patients, pinpoint papules (1-2 mm) were observed on sun-exposed areas, sparring the face and flexural surfaces. All patients were African American women with skin type IV-VI and a mean age of 39.3 years (range 21-52 years). Phototest results were normal in three patients; one patient, who was on glyburide, had a decreased minimal erythema dose to UV-A. ANA testing was negative. Two histopathologic patterns were observed: (i) focal lichenoid and perivascular lymphohistiocytic infiltrate with red blood cell extravasation in four specimens and (ii) superficial and deep interstitial lymphocytic infiltrate with papillary dermal edema in the remaining three specimens. All patients responded to topical corticosteroids, broad-spectrum sunscreens and antihistamines. CONCLUSION: Recognition of this pinpoint papular variant of PMLE in dark-skinned individuals is important in the evaluation and management of these patients.