Vascular malformations encompass a wide range of clinical and anatomic problems including lesions of cosmetic concern to life-threatening conditions. It is imperative to make the correct diagnosis, be aware of the natural history, and choose the correct therapeutic intervention when indicated. Historically there has been a great deal of confusion in the literature regarding the proper nomenclature and classification of vascular malformations. In particular, the term, hemangioma, continues to be widely misused and erroneously applied to almost any type of vascular malformation.

Based on the pioneering classification scheme proposed by Mulliken and Glowacki and the subsequent criteria set forth by the International Society for Study of Vascular Anomalies (ISSVA) as well as our own experience in treating vascular anomalies over the last 3 decades, we have found it useful to divide these lesions into 5 main categories as follows:

• 1
  

  Vascular tumors (infantile hemangioma, congenital hemangioma, kaposiform hemangioendothelioma, and tufted angioma)

  
  
• 2
  

  Fast-flow arteriovenous malformations and congenital fistulas

  
  
• 3
  

  Slow-flow venous malformations

  
  
• 4
  

  Lymphatic malformations

  
  
• 5
  

  Congenital mixed syndromes (Klippel-Trénaunay syndrome [KTS], Parkes-Weber syndrome, and Maffucci syndrome)

Each of these lesions has its own distinct clinical presentation and natural history, and each requires a different approach. Slow-flow venous malformations are by far the most common. Genetic mutations of the endothelial cell-specific TIE-2 receptor tyrosine kinase, a ligand protein involved in the recruitment of mesenchymal cells during vasculogenesis, have been associated with the development of both sporadic and inherited forms of venous malformations. The resulting defect is a weakened tunica media with abnormal elasticity, increased capacitance, and subsequent incompetence of the venous wall, causing stagnant flow and pooling of blood.

Characteristically, patients present with a spongy, compressible soft tissue mass that can become swollen and painful with injury, activity, spontaneous thrombosis, or changes in the hormonal milieu (as occurs during puberty or pregnancy). Secondary skin changes such as angiokeratomas and port-wine stains (capillary venous malformations) are occasionally present.

Based on our experience over the last 3 decades, venous malformations account for more than 80% of all vascular malformations (excluding hemangiomas, which are not vascular malformations but benign endothelial tumors), with less than 1% of these confined to the vulva. Venous malformations can occur anywhere in the body but tend to be particularly symptomatic when they involve the head and neck, the extremities, or the genitalia.

Vulvar venous malformations (VVMs) can cause significant functional and aesthetic impairment. Although there are some predictable patterns identified including increased symptomatology during puberty and pregnancy as a result of changes in the hormonal milieu, activity, trauma, spontaneous thrombosis, etc can also play a contributory role in exacerbating symptoms. Hence, there is variability in severity of symptoms and age at which symptoms develop. Although reportedly rare, the true prevalence remains unknown because the nomenclature used to describe these lesions remains inconsistent. Furthermore, the diagnostic and therapeutic modality of choice is yet to be determined because clinical experience remains relatively limited. We report our experience in a rare series of treated symptomatic slow-flow venous malformations using a staged, multidisciplinary approach.

Materials and Methods

We retrospectively evaluated the clinical course of consecutive patients treated for symptomatic slow-flow VVMs at the Vascular Birthmark Institute of New York (VBI) over a 7 year period (2005-2012). Exemption from approval was obtained from the Institutional Review Board of VBI. Diagnosis was made at the time of the initial consult after a thorough history and physical examination and confirmed by magnetic resonance imaging (MRI) featuring contrast-enhanced cavernous venous spaces on T2-weighted images ( Figure 1 ). There was no evidence of gonadal vein incompetence on MRI.

MRI features

T2-weighted MRI outlines the extent and depth of a slow-flow vulvar venous malformation featuring contrast-enhanced cavernous vascular spaces throughout the vulva and the perineum.

MRI , magnetic resonance imaging.

Nassiri. Vulvar venous malformations. Am J Obstet Gynecol 2013.

All patients underwent direct endovenous sclerotherapy (DEVS) by a single vascular interventionalist using a 1-3% foam solution of the anionic surfactant sodium tetradecyl sulfate (STS). Depending on the size and vascularity of the lesion treated, single or multiple DEVS sessions were required for a maximum total dose of 0.5 mL per kilogram of body weight per session. Greater doses have been associated with hemolysis, impaired renal function, and in rarely cardiopulmonary dysfunction. Once adequate devascularization was achieved via DEVS (determined during each DEVS session via direct percutaneous venography of the lesion by the vascular interventional team), surgical excision and layered primary closure was performed by a team of plastic and reconstructive surgeons and an experienced gynecological surgeon within 24 hours after the last DEVS session. Patients were then followed up closely for assessment of technical outcomes, resolution of presenting symptoms, aesthetic results, and development of complications.

Technique: direct endovenous sclerotherapy

All DEVS sessions were performed under laryngeal mask airway anesthesia to facilitate patient comfort and compliance. Prior to induction of anesthesia, the patient (with parents, in pediatric cases) identified symptomatic areas, and the overlying skin was marked accordingly. This marking correlated closely with the underlying malformation and allowed the operator to prioritize the most symptomatic part of the malformation when multiple sessions were required. In patients with KTS, a peripheral venogram of the affected lower extremity was performed prior to DVS to confirm the adequacy of the deep venous system and to define any major communication between the malformation and the deep veins. In our practice, an ascending venography at the time of the initial DEVS procedure remains the gold standard for assessing the presence of a deep venous system and the detection of anomalous venous conduits.

Guidance for direct puncture of the labial malformations was based on previously marked skin site, palpation of the mass, real-time ultrasound, and MRI. Endoluminal access was achieved using 21-gauge needles or 18- to 20-gauge angiocatheters. The lesion was then studied fluoroscopically during slow endovenous contrast injection. The typical angioarchitecture featured a cavernous meshwork of dilated venous channels with variable drainage patterns into the systemic venous circulation ( Figures 2 and 3 ).

Fluoroscopic features

Endovenous contrast injection study under fluoroscopic guidance outlines the vulvar venous malformation and can be used as a roadmap for direct endovenous sclerotherapy.

Nassiri. Vulvar venous malformations. Am J Obstet Gynecol 2013.

Further fluoroscopic features

Endovenous contrast injection study under fluoroscopic guidance outlines the vulvar venous malformation and can be used as a roadmap for direct endovenous sclerotherapy.

Nassiri. Vulvar venous malformations. Am J Obstet Gynecol 2013.

Various concentrations (1-3%) of STS-ethiodized oil emulsion were injected under fluoroscopic guidance to ensure adequate deposition and to monitor for nontarget embolization into systemic veins. After each deposition of STS, the needle or catheter was withdrawn and the access tract was plugged with a collagen matrix (Surgiflo; Ethicon, Inc, Somerville, NJ) to prevent prolonged puncture site bleeding and backtracking of the agent to the overlying skin. A sterile, antimicrobial adhesive bandage was applied. Patients were admitted for overnight observation, prophylactic antibiotic coverage, analgesia, and oral steroid administration. The latter was initiated to minimize postembolization pain and swelling. When multiple DEVS sessions were required, these were scheduled no closer than 6 weeks apart to allow ample time for inflammation to subside.

Technique: surgical excision

Within 24 hours following the last DEVS session, patients underwent surgical excision of the labial malformation as follows. Under general endotracheal anesthesia, patients were placed in the lithotomy position. The recently embolized labial mass was outlined and excised using a combination of electrocautery and sharp dissection. We aimed to preserve as much of the underlying labial fat pad as possible so to maintain a natural contour. The wound was thoroughly irrigated, and hemostasis was obtained using a combination of suture ligation of residual draining veins, electrocautery, and topical hemostatic agents. Any redundant skin was excised and trimmed to facilitate a more cosmetic closure. A Jackson-Pratt drain was placed into the wound exiting a stab incision placed anteriorly on the mons pubis. This was connected to constant bulb suction and discontinued once drainage was less than 5 mL over 24 hours. All wounds underwent layered primary closure using buried interrupted and running subcuticular absorbable sutures and dressed with a cyanoacrylate-based topical adhesive (Dermabond; Ethicon).