Mycosis fungoides palmaris et plantaris--an unusual variant of cutaneous T-cell lymphoma

Mycosis fungoides (MF) represents a low-risk, cutaneous, non-Hodgkin, T-cell lymphoma with a wide spectrum of clinicopathological manifestations and therefore may mimic a number of other dermatoses. Sometimes the clinical diversity makes the diagnosis of MF, and especially its atypical forms, challenging. We report on an 18-year old male patient, who had been previously diagnosed with palmoplantar eczema. Clinical, histopathological, immunohistochemical and molecular findings revealed an atypical case of MF.

[Pseudosarcomatous variant of a genital fibroepithelial stromal polyp in a pregnancy]

Fibroepithelial stromal polyps are benign neoplasms of the lower genital tract occurring mostly in young to middle-aged women in their reproductive years. Clinically they appear as tender, skin-colored, sack-like tumors and usually have a bland microscopic appearance. Sometimes, especially during pregnancy or with hormone therapy, a worrisome hypercellular and pseudosarcomatous pattern can be seen in the dermis. Awareness of this neoplasm with a possibly high degree of atypia is of crucial importance in order to avoid unnecessary radical surgery.

Proteinase-activated receptor-2 mediates itch: a novel pathway for pruritus in human skin

We examined whether neuronal proteinase-activated receptor-2 (PAR-2) may be involved in pruritus of human skin. The endogenous PAR-2 agonist tryptase was increased up to fourfold in atopic dermatitis (AD) patients. PAR-2 was markedly enhanced on primary afferent nerve fibers in skin biopsies of AD patients. Intracutaneous injection of endogenous PAR-2 agonists provoked enhanced and prolonged itch when applied intralesionally. Moreover, itch upon mast cell degranulation was abolished by local antihistamines in controls but prevailed in AD patients. Thus, we identified enhanced PAR-2 signaling as a new link between inflammatory and sensory phenomena in AD patients. PAR-2 therefore represents a promising therapeutic target for the treatment of cutaneous neurogenic inflammation and pruritus.

Prostaglandin E2 induces vasodilation and pruritus, but no protein extravasation in atopic dermatitis and controls

BACKGROUND

Prostaglandin E(2) (PGE(2)) has well-established vasodilatory effects, whereas its effects on protein extravasation and its sensory effects are less clear.

OBJECTIVE

Vasoactive effects of PGE(2) were correlated to its ability to evoke pain or itch in healthy volunteers and patients with atopic dermatitis (AD).

METHODS

Intradermal microdialysis was used to apply PGE(2) (10(-8)-10(-4) M) via microdialysis capillaries in 8 patients and 8 controls. Large pore size membranes (3000 kd) enabled simultaneous analysis of protein extravasation. Itch and pain sensations were measured psychophysically, and superficial blood flow was measured by laser Doppler imaging.

RESULTS

PGE(2) dose dependently provoked intense local vasodilation, weak pruritus, and pain, but no protein extravasation. No differences were found between patients with AD and controls for any parameter.

CONCLUSION

We conclude that PGE(2) is a potent vasodilator and a weak pruritic agent in normal skin and in patients with AD, but does not provoke increased protein extravasation.

Acute effects of substance P and calcitonin gene-related peptide in human skin--a microdialysis study

Upon activation nociceptors release neuropeptides in the skin provoking vasodilation and plasma protein extravasation in rodents, but only vasodilation in humans. Pivotal peptides in the induction of neurogenic inflammation comprise calcitonin gene-related peptide and substance P, the latter being suggested to act partly via degranulation of mast cells. In this study substance P and calcitonin gene-related peptide-induced vasodilation, protein extravasation, histamine release, and sensory effects were investigated simultaneously in human skin by dermal microdialysis. The vasodilatory prostaglandin E(2) and the mast cell activator codeine served as positive controls. Substance P and calcitonin gene-related peptide applied intradermally via large cut-off plasmapheresis capillaries induced dose-dependent local vasodilation, but only SP provoked protein extravasation in concentrations greater than 10(-9) M. Substance P-induced (10(-8)-10(-6) M) protein extravasation was not accompanied by histamine release and was unaffected by cetirizine (histamine H1 blocker, 200 microg per ml). Only the highest concentration of substance P (10(-5) M) induced significant histamine release. Neither neuropeptide caused any axon reflex erythema or any itch or pain sensation, whereas mast cell degranulation by codeine dose dependently provoked itch, flare, protein extravasation, and histamine release. In human skin calcitonin gene-related peptide and substance P induce vasodilation by a mechanism not involving histamine. No evidence for neuropeptide-induced activation of nociceptors was obtained. Our results suggest that endogenous calcitonin gene-related peptide and substance P have no acute sensory function in human skin. The lack of neurogenic protein extravasation in humans can most probably be attributed to low local concentrations of this neuropeptide still sufficient to exert trophic and immunomodulatory effects (10(-11) M), but too low to induce protein extravasation (10(-8) M) or even mast cell degranulation (10(-5) M). J Invest Dermatol 115:1015-1020 2000

Detection of increased tyrosine phosphorylation in murine Langerhans cells after stimulation with contact sensitizers

The signalling pathways in epidermal Langerhans cells (LC) during activation by contact sensitizers are poorly understood. Recently, we have described an increased phosphorylation of tyrosine residues in human MHC class II-positive cells in vitro following stimulation with contact sensitizers. In the study reported here the formation of phosphotyrosine (p-tyr) in murine epidermal LC upon stimulation with contact sensitizers was examined. By the use of a flow cytometric technique a significant increase in p-tyr was demonstrated in LC stimulated in vitro with the strong contact sensitizers TNCB (2,4,6-trinitro-chlorobenzene) and MCI/MI (5-chloro-2-methylisothiazolinone plus 2-methylisothiazolinone) but not after treatment with the irritants sodium lauryl sulphate or benzoic acid. The protein tyrosine kinase inhibitors genistein and tyrphostin A9, but not tyrphostin AG 1288, were able to block this process significantly. Similar results were obtained using the LC-like dendritic cell line XS52. In addition, Western blot analysis on XS52 cells revealed a selective phosphorylation of two protein bands with a molecular weight between 50 and 60 kDa following stimulation with TNCB. These results demonstrate that contact sensitizers induce an increased phosphorylation of tyrosine residues in murine LC and can be used as the basis for in vivo studies using inhibitors for signal transduction pathways for prevention of primary sensitization to contact sensitizers.