Mosaicism is increasingly recognized as a cause of developmental disorders with the advent of next-generation sequencing (NGS). Mosaic mutations of PIK3CA have been associated with the widest spectrum of phenotypes associated with overgrowth and vascular malformations. We performed targeted NGS using 2 independent deep-coverage methods that utilize molecular inversion probes and amplicon sequencing in a cohort of 241 samples from 181 individuals with brain and/or body overgrowth. We identified PIK3CA mutations in 60 individuals. Several other individuals (n = 12) were identified separately to have mutations in PIK3CA by clinical targeted-panel testing (n = 6), whole-exome sequencing (n = 5), or Sanger sequencing (n = 1). Based on the clinical and molecular features, this cohort segregated into three distinct groups: (a) severe focal overgrowth due to low-level but highly activating (hotspot) mutations, (b) predominantly brain overgrowth and less severe somatic overgrowth due to less-activating mutations, and (c) intermediate phenotypes (capillary malformations with overgrowth) with intermediately activating mutations. Sixteen of 29 PIK3CA mutations were novel. We also identified constitutional PIK3CA mutations in 10 patients. Our molecular data, combined with review of the literature, show that PIK3CA-related overgrowth disorders comprise a discontinuous spectrum of disorders that correlate with the severity and distribution of mutations.

Blue rubber bleb nevus syndrome (Bean syndrome) is a rare, severe disorder of unknown cause, characterized by numerous cutaneous and internal venous malformations; gastrointestinal lesions are pathognomonic. We discovered somatic mutations in TEK, the gene encoding TIE2, in 15 of 17 individuals with blue rubber bleb nevus syndrome. Somatic mutations were also identified in five of six individuals with sporadically occurring multifocal venous malformations. In contrast to common unifocal venous malformation, which is most often caused by the somatic L914F TIE2 mutation, multifocal forms are predominantly caused by double (cis) mutations, that is, two somatic mutations on the same allele of the gene. Mutations are identical in all lesions from a given individual. T1105N-T1106P is recurrent in blue rubber bleb nevus, whereas Y897C-R915C is recurrent in sporadically occurring multifocal venous malformation: both cause ligand-independent activation of TIE2, and increase survival, invasion, and colony formation when expressed in human umbilical vein endothelial cells.

Multifocal lymphangioendotheliomatosis with thrombocytopenia (MLT) is a rare disease characterized by congenital and progressive vascular lesions of the skin and gastrointestinal tract that may be associated with thrombocytopenia and possibly life-threatening gastrointestinal bleeding. Reports published on the disease and treatment strategies are scarce. We present two cases of MLT treated with sirolimus.

Plexiform neurofibromas are benign tumors originating from peripheral nerve sheaths, generally associated with Neurofibromatosis Type 1 (NF1). They are diffuse, painful and sometimes locally invasive, generating cosmetic problems. This report discusses an adolescent patient who presented with an isolated, giant plexiform neurofibroma on her leg that was confused with a vascular lesion due to its clinical aspects. Once the diagnosis was confirmed by surgical biopsy, excision of the lesion was performed with improvement of the symptoms.

Neonatal lupus erythematosus is a very rare disease, clinically characterized by skin lesions that resemble those of subacute or discoid lupus erythematosus and/or congenital heart block. Generally, when patients have skin manifestations, they have no cardiac defects and vice-versa; however, in 10% of cases these manifestations may coexist. Other findings may include hematologic, hepatic and neurological abnormalities. This condition is caused by the transplacental passage of maternal autoantibodies against Ro (95%), La and, less frequently, U1-ribonucleoprotein (U1-RNP). The present case report describes four patients with clinical, histopathological and immunological findings compatible with neonatal lupus erythematosus, their treatment and progress. Keywords: Cutaneous; Heart diseases; Lupus erythematosus, pediatricsResumen: El lupus eritematoso neonatal es una enfermedad poco frecuente, caracterizada clínica-mente por alteraciones cutáneas semejantes al lupus subagudo o discoide y/o bloqueo cardíaco congénito. Generalmente, cuando los pacientes presentan manifestaciones cutáneas, no tienen anormalidades cardiológicas y viceversa, aunque en un 10% de los casos ambas manifestaciones pueden coexistir. Puede acompañarse también de alteraciones hematológicas, hepáticas y neurológicas. Es causado por el pasaje trasplacentario de anticuerpos maternos anti Ro (95%), anti La y menos frecuentemente anti U1RNP. Presentamos cuatro pacientes con hallazgos clínicos, histopatológicos e inmunológicos compatibles con lupus eritematoso neonatal, su tratamiento y evolución.