Naevus vascularis mixtus and mixed vascular naevus syndrome.

Naevus vascularis mixtus (NVM), or mixed vascular naevus (MVN), is a binary phenotype resulting from allelic twin spotting, consisting of a naevus anaemicus paired with a telangiectatic naevus reminiscent of naevus roseus, and caused by a mosaic GNA11 mutation. MVN syndrome is characterized by an NVM associated with soft tissue hypotrophy or central nervous system abnormalities, mainly involving the cerebral vasculature. The differential diagnoses of NVM and its syndrome include vascular twin naevi, syndromes featuring naevus flammeus and other port-wine naevi, and the various types of phacomatosis pigmentovascularis. NVM and MVN syndrome are rare but probably underdiagnosed and under-reported.

Segmental hypomelanosis and hypermelanosis arranged in a checkerboard pattern are distinct naevi: flag-like hypomelanotic naevus and flag-like hypermelanotic naevus.

The categorization of congenital hypo- or hyperpigmented skin lesions following a segmental pattern has been a long-lasting matter of debate and have been reported under various and often incorrect terms. To reassess published hypomelanotic and hypermelanotic lesions that did not follow Blaschko lines nor a phylloid pattern of mosaicism, we carried out an extensive and critical review of the worldwide literature. Seventy-four retrieved cases consisted of lateralized hypomelanotic lesions arranged in a flag-like pattern or appearing as large patches of grossly oval or angulated shape and sharp, serrated margins. Sometimes lesions harboured maculopapular melanocytic naevi or cooccurred with other segmentally arranged naevi. A probably non-random association with extracutaneous anomalies was also reported on rare occasions. In 70 cases, lateralized hypermelanotic patches were arranged in a flag-like pattern that often appeared as large quadrangular patches. Sometimes lesions harboured Spitz naevi. Ten cases belonged to phacomatosis melanorosea, whereas several others were part of so far uncategorized cases of phacomatosis pigmentovascularis. Flag-like hypomelanosis is a distinct naevus type, for which the term 'flag-like hypomelanotic naevus' is suggested. Its cooccurrence with extracutaneous abnormalities might represent a specific syndrome. Flag-like hypermelanosis is a distinct naevus type, for which the term 'flag-like hypermelanotic naevus' is suggested. Its co-occurrence with naevus roseus defines phacomatosis melanorosea. Flag-like hypermelanotic naevus should be distinguished from the checkerboard-like areas of darker skin as observed in chimaeras.

Melanocytic naevi clustered on normal background skin.

Several types of maculopapular melanocytic naevi can occur in a multiple form, and be arranged in a nonrandom fashion on the skin. The most frequently reported segmentally grouped naevi are lentigines. Two types of segmentally arranged lentigines probably exist. The first is associated with neurofibromatosis (NF)1 or NF1 signs, features scattered light-brown lesions and can be considered a type of mosaic NF1. By contrast, non-NF1 associated lesions are characterized by densely packed, dark lesions, and can be defined as 'non-NF1 checkerboard-arranged lentigines'. Blue naevi, Spitz naevi and common acquired melanocytic naevi can occur, clustered in an agminated (or cannonball) shape. However, if large enough, they always follow a checkerboard pattern. Hence, such mosaic conditions should be termed 'checkerboard-arranged blue naevi', 'checkerboard-arranged Spitz naevi' and 'checkerboard-arranged common acquired melanocytic naevi'. Segmentally arranged dysplastic melanocytic naevi probably represent a mosaic form of dysplastic naevus syndrome. Dysplastic melanocytic naevi confined to a cutaneous segment could be defined as 'isolated segmental dysplastic naevus syndrome', while segmentally arranged dysplastic melanocytic naevi co-occurring with widespread, nonsegmental dysplastic melanocytic naevi might configure a 'superimposed segmental dysplastic naevus syndrome'. Small congenital melanocytic naevi are always grouped along Blaschko lines. The only other instances following Blaschko lines are the so-called 'linear lentiginous naevus' and a unique case of multiple deep penetrating naevi.

Effects of tacrolimus ointment on Toll-like receptors in atopic dermatitis.

BACKGROUND: Alterations of Toll-like receptors (TLRs) seem to play a role in susceptibility to atopic dermatitis (AD). AIM: To investigate the expression of TLRs in moderate to severe chronic AD in adults before and after a 3-week treatment with 0.1% tacrolimus ointment, compared with 0.1% topical hydrocortisone-17-butyrate. METHODS: In total, 21 adult patients with AD were enrolled: 11 were given tacrolimus ointment and 10 were given hydrocortisone butyrate; a further 6 healthy adults formed the control group. The clinical efficacy of the treatment was assessed using the SCORing Atopic Dermatis (SCORAD) index. Biopsies were taken from lesional skin before and after treatment, which were stained immunohistochemically with monoclonal antibodies to TLR-1, -2, -4 and -9. RESULTS: Both 3-week topical treatments improved signs and symptoms in all 21 patients considered, with no significant difference between the two groups. In the skin of patients with AD, TLR-1 was overexpressed and TLR-2 underexpressed compared with healthy controls, whereas no differences were found for TLR-4 and TLR-9. Staining for TLR-1 was decreased in both groups after treatment. AD specimens had higher levels of TLR-2 expression after either treatment compared with baseline, and levels were higher after tacrolimus treatment than after hydrocortisone butyrate. Neither tacrolimus nor hydrocortisone butyrate affected expression of TLR-4 or TLR-9. CONCLUSION: Short-term therapy with tacrolimus ointment reduced expression of TLR-1, which may inhibit the antimicrobial potential of TLR-2, and also reversed the impairment of TLR-2 in AD lesions. Expression of TLR-4 and TLR-9 was not affected by tacrolimus.

Skin manifestations of immunodeficiencies in children.

Immunodeficiency is a state in which the immune system's ability to fight infectious diseases is compromised or entirely absent. Most cases of immunodeficiency are acquired (secondary) but some people are born with defects in the immune system, or primary immunodeficiency. More than 140 distinct genes have been identified, which abnormalities account for more than 200 different forms of primary immunodeficiencies. The skin may be one of the organs involved in immunodeficiencies and in a number of primary immunodeficiency syndromes the skin is one of the main clues to the diagnosis and dermatologists may be the first to appreciate an immune defect in their patients. From "A" of well-known ataxia-telangiectasia to "Z" of recently identified zeta-chain (TCR) associated protein kinase 70kDa (ZAP-70) deficiency, this review attempts to provide a complete and up-to-date summary of all known primary immunodeficiencies featuring skin manifestations and presenting in the pediatric population. Given the vastness of the topic etiopathogenesis, extracutaneous manifestations, diagnosis, treatment and prognosis were not discussed unless briefly. We hope that this effort will help specialists to facilitate the recognition of primary immunodeficiencies and therefore early diagnosis and management.