RASA1 mutations and associated phenotypes in 68 families with capillary malformation-arteriovenous malformation.

Capillary malformation-arteriovenous malformation (CM-AVM) is an autosomal-dominant disorder, caused by heterozygous RASA1 mutations, and manifesting multifocal CMs and high risk for fast-flow lesions. A limited number of patients have been reported, raising the question of the phenotypic borders. We identified new patients with a clinical diagnosis of CM-AVM, and patients with overlapping phenotypes. RASA1 was screened in 261 index patients with: CM-AVM (n = 100), common CM(s) (port-wine stain; n = 100), Sturge-Weber syndrome (n = 37), or isolated AVM(s) (n = 24). Fifty-eight distinct RASA1 mutations (43 novel) were identified in 68 index patients with CM-AVM and none in patients with other phenotypes. A novel clinical feature was identified: cutaneous zones of numerous small white pale halos with a central red spot. An additional question addressed in this study was the "second-hit" hypothesis as a pathophysiological mechanism for CM-AVM. One tissue from a patient with a germline RASA1 mutation was available. The analysis of the tissue showed loss of the wild-type RASA1 allele. In conclusion, mutations in RASA1 underscore the specific CM-AVM phenotype and the clinical diagnosis is based on identifying the characteristic CMs. The high incidence of fast-flow lesions warrants careful clinical and radiologic examination, and regular follow-up.

Unusual and recently described cutaneous atrophic disorders.

Cutaneous atrophic conditions are typically caused by changes in the dermis or subcutaneous tissue, sometimes consisting of the loss of a single fiber type. Since a significant decrease of subepidermal tissue is necessary for these lesions to be macroscopically atrophic, many conditions may not be appreciated as atrophy in the clinical setting. Clinicians should be familiar with the common or classic disorders causing cutaneous atrophy; however, there are a few new or rarely described atrophic conditions which are more difficult to identify and may not be atrophic clinically. This paper serves to describe the salient clinical and histological features of these new or rare disorders.

Congenital atrophic dermatofibrosarcoma protuberans in a 7-month-old boy treated with Mohs micrographic surgery.

Dermatofibrosarcoma protuberans is a rare, malignant, slow-growing, locally invasive tumor of the skin. Although most cases are acquired and diagnosed in adulthood, there have been an increasing number of congenital dermatofibrosarcoma protuberans mimicking benign birthmarks described in the literature. The clinical presentation of this tumor is often one of an indurated exophytic plaque or nodule; however, a rare variant can present as atrophic or sclerotic in nature. We report a case of congenital atrophic dermatofibrosarcoma protuberans of the groin in a 7-month-old boy, successfully treated with Mohs micrographic surgery.