Rectosigmoid colon venous malformation successfully treated with propranolol and celecoxib

Direct stick embolization of a rectal venous malformation via transanal minimally invasive surgery

Rectal venous malformations (VMs) are rare clinical entities with variable patterns of presentation. Treatment requires unique, targeted strategies based on the symptoms, associated complications, and location, depth, and extent of the lesion. We present a rare case of a large, isolated rectal VM treated by direct stick embolization (DSE) using transanal minimally invasive surgery (TAMIS). A 49-year-old man had presented with a rectal mass incidentally detected on computed tomography urography. Magnetic resonance imaging and endoscopy revealed an isolated rectal VM. Elevated D-dimer levels concerning for localized intravascular coagulopathy warranted the use of prophylactic rivaroxaban. To avoid invasive surgery, DSE using TAMIS was performed successfully without complications. His postoperative recovery was uneventful, aside from a self-limiting and expected course of postembolization syndrome. To the best of our knowledge, this is the first reported case of TAMIS-assisted DSE of a colorectal VM. TAMIS shows promise for more widespread use in the minimally invasive, interventional management of colorectal vascular anomalies.

Clinical Characteristics and Management of Colorectal Vascular Malformation in Children: A Retrospective Study of 23 Cases

INTRODUCTION

 The objective of this study is to summarize the clinical characteristics and management of rare diseases of colorectal vascular malformation (CRVM) in children.

METHODS

 We retrospectively analyzed the clinical data of CRVM patients admitted to the Children's Hospital of Fudan University from 2004 to 2019.

RESULTS

 A total of 23 cases (16 males, 7 females) were enrolled. The median age of symptom onset was 1.4 years. Hematochezia and anemia were cardinal symptoms. Fourteen patients (60.9%) were misdiagnosed as anal fissures (n = 4), internal hemorrhoids (n = 3), rectal polyps (n = 2), inflammatory bowel disease (n = 2), portal hypertension (n = 2), and Meckel's diverticulum (n = 1), respectively. The average time from symptom onset to diagnosis was 4.5 ± 4.4 years. Other vascular malformations were detected in eight patients (34.8%). All patients showed a positive anomalous vascular image on contrast-enhanced computed tomography (CT) or magnetic resonance imaging (MRI). The sensitivity of colonoscopy in the diagnosis of CRVM was 82.6% (19/23). A total of 21 patients underwent a modified Soave procedure. The lesions were mostly restricted to the colorectum and showed transmural diffuse distribution, with an average length of 20 ± 5.4 cm. Two patients (9.5%) experienced surgical complications. Bloody stools reappeared in two patients (9.5%), and colonoscopy showed abnormal angiogenesis at the anastomotic site, which were cured by sclerotherapy and/or electrocautery. The median follow-up time was 78 months. Bloody stools were absent at the last time of follow-up, and hemoglobin was in the normal range for all patients.

CONCLUSION

 The identification of CRVM in children often is delayed. Colonoscopy, CT, and MRI are essential in making the correct diagnosis. The modified Soave procedure is safe and feasible to treat CRVM in children. Endoscopic sclerotherapy and/or electrocautery can be used for residual lesions.

Cell Populations Expressing Stemness-Associated Markers in Vascular Anomalies

Treatment of vascular anomalies (VAs) is mostly empirical and, in many instances unsatisfactory, as the pathogeneses of these heterogeneous conditions remain largely unknown. There is emerging evidence of the presence of cell populations expressing stemness-associated markers within many types of vascular tumors and vascular malformations. The presence of these populations in VAs is supported, in part, by the observed clinical effect of the mTOR inhibitor, sirolimus, that regulates differentiation of embryonic stem cells (ESCs). The discovery of the central role of the renin-angiotensin system (RAS) in regulating stem cells in infantile hemangioma (IH) provides a plausible explanation for its spontaneous and accelerated involution induced by β-blockers and ACE inhibitors. Recent work on targeting IH stem cells by inhibiting the transcription factor SOX18 using the stereoisomer R(+) propranolol, independent of β-adrenergic blockade, opens up exciting opportunities for novel treatment of IH without the β-adrenergic blockade-related side effects. Gene mutations have been identified in several VAs, involving mainly the PI3K/AKT/mTOR and/or the Ras/RAF/MEK/ERK pathways. Existing cancer therapies that target these pathways engenders the exciting possibility of repurposing these agents for challenging VAs, with early results demonstrating clinical efficacy. However, there are several shortcomings with this approach, including the treatment cost, side effects, emergence of treatment resistance and unknown long-term effects in young patients. The presence of populations expressing stemness-associated markers, including transcription factors involved in the generation of induced pluripotent stem cells (iPSCs), in different types of VAs, suggests the possible role of stem cell pathways in their pathogenesis. Components of the RAS are expressed by cell populations expressing stemness-associated markers in different types of VAs. The gene mutations affecting the PI3K/AKT/mTOR and/or the Ras/RAF/MEK/ERK pathways interact with different components of the RAS, which may influence cell populations expressing stemness-associated markers within VAs. The potential of targeting these populations by manipulating the RAS using repurposed, low-cost and commonly available oral medications, warrants further investigation. This review presents the accumulating evidence demonstrating the presence of stemness-associated markers in VAs, their expression of the RAS, and their interaction with gene mutations affecting the PI3K/AKT/mTOR and/or the Ras/RAF/MEK/ERK pathways, in the pathogenesis of VAs.

Celecoxib as a Potential Treatment for Intractable Lymphatic Malformation

Lymphatic malformation (LM) is a congenital disorder resulting from an abnormal development of lymphatic vessels. LM may result in problems of cosmesis and functional impairment, including airway compression. An 11-year-old girl was referred to our department with increasing dysphagia caused by a large left cervical LM with a long history of treatment. Because of the LM location, surgical resection was not an option, and various therapies, including use of picibanil, had proven ineffective. Celecoxib treatment (100 mg/day) was initiated for local pain management. Softening of the lesion was observed 2 weeks after treatment initiation, and the dose was increased to 200 mg/day with additional shrinking of the LM over the next 2 weeks. With parental consent, celecoxib was continued, with a 65% reduction in volume achieved at 6 months. The patient discontinued treatment at 12 months, and the LM volume increased. Control over the LM was achieved with resumption of celecoxib treatment. After 2 years of treatment, the LM persists, but the size of the malformation is significantly smaller. No adverse effects of celecoxib treatment were observed. The anti-cyclooxygenase-2 effect of celecoxib prevented lymphatic vessel growth through an inhibition of cyclooxygenase-2 activity in the conversion of prostaglandin to prostaglandin E2. In conclusion, celecoxib may be a promising therapeutic agent for LM management.

Embryonic Stem Cell-like Population within Venous Malformation Expresses the Renin-Angiotensin System

Background

We have recently demonstrated the presence of a NANOG⁺/pSTAT3⁺/OCT4⁺/SOX2⁺/SALL4⁺/CD44⁺ embryonic stem cell (ESC)-like subpopulation localized to the endothelium and a NANOG⁺/pSTAT3⁺/SOX2⁺/CD44⁺ subpopulation outside of the endothelium, within subcutaneous VM (SCVM) and intramuscular VM (IMVM). We have also shown the expression of components of the renin-angiotensin system (RAS): (pro)renin receptor (PRR); angiotensin converting enzyme (ACE), angiotensin II receptor 1 (ATIIR1) and angiotensin II receptor 2 (ATIIR2), in both SCVM and IMVM. This study investigated whether the ESC-like subpopulations within SCVM and IMVM expressed the RAS.

Methods

Formalin-fixed paraffin-embedded sections of two representative samples from each of the seven SCVM and seven IMVM patients included in our previous studies underwent dual immunofluorescence (IF) immunohistochemical (IHC) staining for ESC marker OCT4 or SOX2 with PRR, ACE, ATIIR1, and ATIIR2.

Results

IF IHC staining demonstrated the expression PRR by the OCT4⁺ cells on the endothelium and outside the endothelium in SCVM and IMVM. ACE was expressed by the SOX2⁺ cells, predominantly in the endothelium in SCVM and IMVM. ATIIR1 was expressed by the SOX2⁺ cells on the endothelium and outside the endothelium in SCVM and IMVM. ATIIR2 was expressed by the OCT4⁺ endothelium and outside the endothelium in SCVM and IMVM.

Conclusions

Components of the RAS are expressed by ESC-like subpopulations within both SCVM and IMVM. These primitive subpopulations may be a novel therapeutic target by manipulation of the RAS using existing medications.

Expression of the Components of the Renin-Angiotensin System in Venous Malformation

BACKGROUND

Venous malformation (VM) is the most common form of vascular malformation, consisting of a network of thin-walled ectatic venous channels with deficient or absent media. This study investigated the expression of the components of the renin-angiotensin system (RAS), namely, (pro)renin receptor (PRR), angiotensin-converting enzyme (ACE), angiotensin II receptor 1 (ATIIR1), and angiotensin II receptor 2 (AIITR2) in subcutaneous (SC) and intramuscular (IM) VM.

MATERIALS AND METHODS

SC (n = 7) and IM (n = 7) VM were analyzed for the expression of PRR, ACE, ATIIR1, and ATIIR2 using 3,3-diaminobenzidine and immunofluorescent (IF) immunohistochemical (IHC) staining and NanoString gene expression analysis.

RESULTS

IHC staining showed expression of PRR, ACE, and ATIIR1, and faint expression of ATIIR2 in the endothelium of SC and IM VM. Furthermore, ATIIR2 was expressed by cells away from the endothelium in both SC and IM VM lesions examined. NanoString analysis demonstrated the presence of PRR, ACE, and ATIIR1 but not ATIIR2.

CONCLUSION

The presence of PRR, ACE, ATIIR1, and potentially ATIIR2, in both SC and IM VM, suggests a role for the RAS in the biology of VM. This novel finding may lead to a mechanism-based therapy for VM.