Large plaque-like glomuvenous malformation (glomangioma) simulating venous malformation

The concept of type 2 segmental mosaicism, expanding from dermatology to general medicine

In autosomal dominant skin disorders, the well-known type 1 segmental mosaicism reflects heterozygosity for a postzygotic new mutation. By contrast, type 2 segmental mosaicism originates in a heterozygous embryo from an early postzygotic mutational event giving rise to loss of the corresponding wild-type allele, which results in a pronounced segmental involvement being superimposed on the ordinary, non-segmental phenotype. Today, this concept has been proven by molecular analysis in many cutaneous traits. The purpose of this review was to seek publications of cases suggesting an extracutaneous manifestation of type 2 segmental mosaicism. Case reports documenting a pronounced extracutaneous segmental involvement were collected from the literature available in PubMed and from personal communications to the author. Pertinent cases are compared to the description of cutaneous segmental mosaicism of type 1 or type 2 as reported in a given trait. In total, reports suggesting extracutaneous type 2 segmental mosaicism were found in 14 different autosomal dominant skin disorders. In this way, clinical evidence is accumulated that extracutaneous type 2 segmental mosaicism does likewise occur in many autosomal dominant skin disorders. So far, however, molecular proof of this particular form of mosaicism is lacking. The present review may stimulate readers to inform colleagues of other specialties on this new concept, in order to initiate further research in this particular field of knowledge that has important implications for diagnosis, treatment and genetic counselling.

Subfascial involvement in glomuvenous malformation

OBJECTIVE

Glomuvenous malformation (GVM) is an inherited autosomal dominant trait. The lesions, which appear as bluish nodules or plaque-like cutaneous elevations, are usually tender and more firm than sporadic venous malformations. Conventionally, the lesions are thought to be limited to the cutaneous and subcutaneous tissue planes. The objective was to characterize the depth of involvement of GVM lesions.

MATERIALS AND METHODS

Magnetic resonance imaging (MRI) findings in GVM were retrospectively evaluated by two radiologists. The signal characteristics, tissue distribution, pattern of contrast enhancement of the lesions in GVM were documented.

RESULTS

Thirty patients (19 female) aged 1-35 years (mean 18 years) were diagnosed with GVM based on clinical features (n = 20) and/or histopathological findings (n = 10). The lesions were present in the lower extremity (n = 15), upper extremity (n = 6), cervico-facial region (n = 6), pelvis (n = 2), and chest wall (n = 1). All patients had skin and subcutaneous lesions. Fifty percent of the patients (n = 15) demonstrated subfascial intramuscular (n = 15), intra-osseous (n = 1), and intra-articular involvement (n = 1).

CONCLUSION

Contrary to the conventional belief that GVMs are generally limited to the skin and subcutaneous tissue, deep subfascial extension of the lesions is common.

Large plaque-like glomangioma in a patient with multiple glomus tumours: review of imaging and histology

Glomus tumours are benign tumours of the temperature-sensitive neuromyoarterial glomus body, present within the dermis, which are most commonly seen as solitary subungual lesions on the arms. Multiple glomus tumours or glomangiomas are a less common subtype of extradigital glomus tumours, which very rarely present as large plaque-like dermal lesions. Glomangiomas do not often show the classic triad of symptoms associated with glomus tumours, namely: pain, point tenderness on compression, and temperature sensitivity. As a result of this and of their atypical morphology, they can often be misdiagnosed as vascular malformations (VMs), resulting in delayed diagnosis and inappropriate treatment. We report a 29-year-old man with multiple extradigital glomus tumours that had been present since childhood, with the lesion on the patient's leg being the largest plaque-like glomangioma yet reported, to our knowledge. Spectral greyscale and Doppler shift ultrasonography showed multiple, tubulonodular, ectatic, noncompressible, vascular structures with aberrant flow within the thickened dermis. Using magnetic resonance imaging, low to intermediate signal was seen on T1-weighted images and high signal on T2-weighted images, and there was florid enhancement with gadolinium, with no evidence of extension into muscle or bone. Histology showed abnormal, dilated, thin-walled, vascular channels lined with multiple layers of glomus cells, confirming the diagnosis of a glomangioma. We discuss imaging techniques for plaque-like glomangiomas, and review the clinical, radiological and histological characteristics that help differentiate them from other superficial VMs.

Genotypes and phenotypes of 162 families with a glomulin mutation

A decade ago, we identified a novel gene, glomulin (GLMN) in which mutations cause glomuvenous malformations (GVMs). GVMs are bluish-purple cutaneous vascular lesions with characteristic glomus cells in the walls of distended venous channels. The discovery of the genetic basis for GVMs allowed the definition of clinical features to distinguish GVMs from other venous anomalies. The variation in phenotype was also highlighted: from a single punctate blue dot to a large plaque-like lesion. In this study, we screened GLMN in a large cohort of patients to broaden the spectrum of mutations, define their frequency and search for possible genotype-phenotype correlations. Taking into account 6 families published by others, a mutation in GLMN has been found in 162 families. This represents 40 different mutations; the most frequent one being present in almost 45% of them. Expressivity varies largely, without a genotype/phenotype relationship. Among 381 individuals with a mutation, we discovered 37 unaffected carriers, implying a penetrance of 90%. As nonpenetrant individuals may transmit the disease to their descendants, knowledge on the mutational status is needed for appropriate genetic counseling.

Lower extremity glomus tumors: comprehensive review for surgeons

The diagnosis of a lower extremity glomus tumor (GT) is often delayed owing to the lack of awareness and low level of suspicion by the treating physician. GT is thought to arise from cutaneous arteriovenous connections, often involving the nail beds. The unusual location of the lower extremity often leads to missed or delayed diagnosis and management. Surgical excision of GT is often curative and provides significant symptomatic relief. There is a paucity of information in regard to GT in general, especially among vascular surgeons. The aim of this report is to make the surgical community more aware of this disease entity based on the analysis of our own experience and review of the literature.