Fostering research in pediatric interventional radiology: needs assessment and suggestions for support.

BACKGROUND: Due to the rarity of pediatric diseases, collaborative research is the key to maximizing the impact of research studies. A research needs assessment survey was created to support initiatives to foster pediatric interventional radiology research. OBJECTIVE: To assess the status of pediatric interventional radiology research, identify perceived barriers, obtain community input on areas of research/education/support, and create metrics for evaluating changes/responses to programmatic initiatives. MATERIALS AND METHODS: A survey link was sent to approximately 275 members of the Society for Pediatric Interventional Radiology (SPIR) between May and October 2020. Data was collected using a web-based interface. Data collected included practice setting, clinical role, research experience, research barriers, and suggestions for future initiatives. RESULTS: Fifty-nine surveys were analyzed with a staff physician survey response rate of 28% (56/198). A wide range of practice sizes from 15 countries were represented. Respondents were predominantly staff physicians (95%; 56/59) with an average of 11 years (range: 1-25 years) of clinical experience working at academic or freestanding children's hospitals. A total of 100% (59/59) had research experience, and 70% (41/58) had published research with a mean of 30 peer-reviewed publications (range: 1-200). For job security, 56% (33/59) of respondents were expected or required to publish, but only 19% (11/58) had research support staff, and 42% (25/59) had protected research time, but of those, 36% (9/25) got the time "sometimes or never." Lack of support staff, established collaborative processes, and education were identified as top barriers to performing research. CONCLUSIONS: The needs assessment survey demonstrated active research output despite several identified barriers. There is a widespread interest within the pediatric interventional radiology community for collaborative research.

Surgical management of pediatric renovascular hypertension and midaortic syndrome at a single-center multidisciplinary program.

OBJECTIVE: To evaluate the outcomes of various surgical approaches in the treatment of renovascular hypertension and midaortic syndrome (MAS) in children. METHODS: We performed a retrospective medical record review of patients who had undergone surgery for renovascular hypertension from 2010 to 2018 at our center under the care of a multidisciplinary team. The operative interventions included mesenteric artery growth improves circulation (MAGIC), tissue expander-stimulated lengthening of arteries (TESLA), aortic bypass using polytetrafluorethylene, renal artery reimplantation, and autotransplantation. The MAGIC procedure uses the meandering mesenteric artery as a free conduit for aortic bypass. The TESLA procedure is based on lengthening the normal distal aorta and iliac arteries by gradual filling of a retroaortic tissue expander for several weeks, followed by resection of the stenotic aorta and subsequent primary reconstruction. RESULTS: A total of 39 patients were identified, 10 with isolated renal artery stenosis, 26 with MAS, and 3 with systemic inflammatory vasculitis. The median age at presentation and surgery was 6.4 years (range, 0-16.3 years) and 9.3 years (range, 0-9.2 years), respectively. The MAS-associated syndromes included neurofibromatosis type 1 (15.4%) and Williams syndrome (5.1%), although most cases were idiopathic. At surgery, 33.3% had had stage 1 hypertension (HTN), 53.8% stage 2 HTN, and 12.8% normal blood pressure with a median of three antihypertensive medications. Follow-up of 37 patients at a median of 2.5 years demonstrated normal blood pressure in 86.1%, stage 1 HTN in 8.3%, and stage 2 HTN in 5.6%, with a median of one antihypertensive medication for the entire cohort. CONCLUSIONS: The patterns of vascular involvement leading to renovascular hypertension in children are variable and complex, requiring thoughtful multidisciplinary planning and surgical decision-making. The MAGIC and TESLA procedures provide feasible approaches for aortic bypass and reconstruction using autologous tissues and will result in normalization of blood pressure in 85% of children 2.5 years after surgery.

Congenital Disseminated Pyogenic Granuloma: Characterization of an Aggressive Multisystemic Disorder.

OBJECTIVE: To describe the clinical, radiologic, and histopathologic features of "congenital disseminated pyogenic granuloma" involving various organs with high morbidity related to cerebral hemorrhagic involvement. STUDY DESIGN: We searched the database of the Vascular Anomalies Center at Boston Children's Hospital from 1999 to 2019 for patients diagnosed as having multiple vascular lesions, visceral vascular tumors, congenital hemangiomatosis, multiple pyogenic granulomas, or multiple vascular lesions without a definite diagnosis. A retrospective review of the medical records, photographs, histopathologic, and imaging studies was performed. Only patients with imaging studies and histopathologic diagnosis of pyogenic granuloma were included. RESULTS: Eight children (5 male, 3 female) had congenital multifocal cutaneous vascular tumors. Lesions also were found in the brain (n = 7), liver (n = 4), spleen (n = 3), muscles (n = 4), bone (n = 3), retroperitoneum (n = 3), and intestine/mesentery (n = 2). Less commonly affected were the spinal cord, lungs, kidneys, pancreas, and adrenal gland (n = 1 each). The mean follow-up period was 21.8 months. The cerebral and visceral lesions were hemorrhagic with severe neurologic sequelae. The histopathologic diagnosis was pyogenic granuloma with prominent areas of hemorrhage and necrosis. The endothelial cells had enlarged nuclei, pale cytoplasm and were immunopositive for CD31 and negative for D2-40 and glucose transporter 1. CONCLUSIONS: Congenital disseminated pyogenic granuloma is a distinct multisystemic aggressive disorder that primarily affects the skin, brain, visceral organs, and musculoskeletal system. Differentiation of this entity from other multiple cutaneous vascular lesions is critical because of possible cerebral hemorrhagic involvement.

Clinical characterization and long-term outcomes in pediatric epithelioid hemangioendothelioma.

There is a paucity of information about the clinical characteristics and long-term outcomes of pediatric epithelioid hemangioendothelioma (EHE), a rare vascular neoplasm commonly presenting in adulthood. In our case series of 24 patients with EHE aged 2-26 years, the majority presented with multi-organ disease. Progression was seen in 63% of patients with a mean time to progression of 18.4 months (range: 0-72). Three patients treated with sirolimus achieved stable disease or partial response for >2.5 years. Longitudinal prospective pediatric studies are needed to develop standardized approaches to surgical and medical management.

Two-hour Observation After Liver Biopsy in Children: Clinical and Economic Outcome of a Quality Improvement Intervention.

OBJECTIVE: Following percutaneous liver biopsy performed at our institution on an outpatient basis, children traditionally were observed for 4 hours then discharged after verifying a stable hematocrit level. In June 2015, we adopted a quality improvement project with shorter 2-hour observation for patients with no known risks and the hematocrit test was abandoned.The purpose of this study is to evaluate the clinical and economic outcomes of early discharge of children following liver biopsy. METHODS: We analyzed data on 2 groups of children who underwent ultrasound-guided nontargeted core needle liver biopsy performed on outpatient basis. Group A (100 procedures with 4-hour postprocedural observation time and hematocrit test) was compared with group B (100 procedures with 2-hour observation without hematocrit test). RESULTS: Group A consisted of 92 patients (43 boys; 49 girls) with a mean age of 11.1 years and mean weight of 52.6 kg. Group B had 92 patients (47 boys; 45 girls) with a mean age of 8.9 years and mean weight of 40.5 kg. The mean length of observation was 281 minutes (range 204-540 minutes) and 147 minutes (range 86-332 minutes) for groups A and B, respectively. The mean recovery charges were reduced by 35% per procedure in group B. The tissue obtained was sufficient for pathologic diagnosis in all procedures. There were no biopsy-related complications in either group. CONCLUSIONS: Enhanced recovery with early discharge of low-risk children after 2-hour observation following percutaneous liver biopsy can be safely implemented without adversely affecting the outcome. Shorter postbiopsy observation can be cost-saving and may potentially improve patient satisfaction.

Fibroadipose Vascular Anomaly in the Upper Extremity: A Distinct Entity With Characteristic Clinical, Radiological, and Histopathological Findings.

PURPOSE: Fibroadipose vascular anomaly (FAVA) is an intramuscular vascular malformation that has been recently described as a distinct clinical entity. The clinical, radiological, and histopathological characteristics of FAVA in the upper extremity are reviewed. METHODS: This was a retrospective case series of upper-extremity FAVA lesions. RESULTS: We reviewed 19 patients with FAVA of the upper limb. Pain, stiffness, swelling, and flexion contractures were the most common presentations. Except for one lesion confined to the hand, all lesions either presented with or developed a contracture within 10 years. Ten patients underwent surgical debulking. Six required tendon transfer reconstruction and 3 necessitated a free functional muscle transfer. CONCLUSIONS: Fibroadipose vascular anomaly in the upper extremity requires an accurate diagnosis and may benefit from early referral to a multidisciplinary vascular anomaly center with experienced hand surgeons. Compression garments, propranolol, and sclerotherapy seem to be ineffective. Surgical resection focused on symptomatic regions with appropriate reconstruction may have benefit in salvage of limbs with compromised function. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Surgical Management of Fibroadipose Vascular Anomaly of the Lower Extremities.

BACKGROUND: Fibroadipose vascular anomaly (FAVA) is a recently-defined vascular malformation often involving the extremities and presenting in childhood. Patients may present to orthopaedic surgeons with pain, swelling, joint contractures, and leg length discrepancy. There is no established therapy or treatment paradigm. We report on outcomes following surgical excision for patients with this condition. METHODS: Between 2007 and 2016, all 35 patients that underwent excision of lower-extremity FAVA were retrospectively reviewed using a combination of medical records, radiologic findings, and telemedicine reviews. RESULTS: Mean age at initial presentation was 12.3±6.8 years. Mean follow-up from time of definitive diagnosis at our institution was 66 months (range: 12 to 161 mo). Mean follow-up after surgery was 35 months (range: 6 to 138 mo). Females were affected more than males (71% vs. 29%). The most common location of FAVA was in the calf (49%), followed by the thigh (40%). The most commonly involved muscle was gastrocnemius (29%), followed by the quadriceps (26%). At latest follow-up after surgery, there was an improvement in the proportion of patients with pain at rest (63% vs. 29%), pain with activity (100% vs. 60%), as well as analgesia use (94% vs. 37%). Fourteen patients (40%) had symptomatic residual disease or recurrence of FAVA requiring further treatment. Six patients (17%) required further surgery and 6 (17%) required further interventional radiologic procedures. Three patients (9%) required eventual amputation for intractable pain and loss of function. Lesions with direct nerve involvement were associated with persistent neuropathic symptoms at latest follow-up (P=0.002) as well as symptomatic residual disease and/or recurrence requiring further treatment (P=0.01). Seventeen patients (49%) had 19 preoperative joint contractures. Eighteen of the 19 contractures (95%) had sustained improvement at latest follow-up. CONCLUSIONS: In carefully selected patients, surgical excision of FAVA results in improvement of symptoms. However, symptomatic residual disease and/or recurrence are not uncommon. Direct nerve involvement is associated with a worse outcome. LEVEL OF EVIDENCE: Level IV-case series.

A somatic activating NRAS variant associated with kaposiform lymphangiomatosis.

PURPOSE: Kaposiform lymphangiomatosis (KLA) is a rare, frequently aggressive, systemic disorder of the lymphatic vasculature, occurring primarily in children. Even with multimodal treatments, KLA has a poor prognosis and high mortality rate secondary to coagulopathy, effusions, and systemic involvement. We hypothesized that, as has recently been found for other vascular anomalies, KLA may be caused by somatic mosaic variants affecting vascular development. METHODS: We performed exome sequencing of tumor samples from five individuals with KLA, along with samples from uninvolved control tissue in three of the five. We used digital polymerase chain reaction (dPCR) to validate the exome findings and to screen KLA samples from six other individuals. RESULTS: We identified a somatic activating NRAS variant (c.182 A>G, p.Q61R) in lesional tissue from 10/11 individuals, at levels ranging from 1% to 28%, that was absent from the tested control tissues. CONCLUSION: The activating NRAS p.Q61R variant is a known "hotspot" variant, frequently identified in several types of human cancer, especially melanoma. KLA, therefore, joins a growing group of vascular malformations and tumors caused by somatic activating variants in the RAS/PI3K/mTOR signaling pathways. This discovery will expand treatment options for these high-risk patients as there is potential for use of targeted RAS pathway inhibitors.

Tissue expander-stimulated lengthening of arteries for the treatment of midaortic syndrome in children.

BACKGROUND: Midaortic syndrome (MAS) is a rare condition characterized by stenosis of the abdominal aorta. Patients with disease refractory to medical management will usually require either endovascular therapy or surgery with use of prosthetic graft material for bypass or patch angioplasty. We report our early experience with a novel approach using a tissue expander (TE) to lengthen the normal native arteries in children with MAS, allowing primary aortic repair without the need for prosthetic graft material. METHODS: We conducted a retrospective review of patients with MAS undergoing the TE-stimulated lengthening of arteries (TESLA) procedure at our institution from 2010 to 2014. Data are presented as mean (range). RESULTS: Five patients aged 4.8 years (3-8 years) underwent the TESLA procedure. Stages of this procedure include the following: stage I, insertion of retroaortic TE; stage II, serial TE injections; and stage III, final repair with excision of aortic stenosis and primary end-to-end aortic anastomosis. Stage II was completed in 4 months (1-9 months) with 12 (7-20) TE injections. Goal lengthening was achieved in all patients. Stage III could not be completed in one patient because of extreme aortic inflammation, which precluded safe excision of the aortic stenosis and required use of a prosthetic bypass graft. The other four patients completed stage III with two (one to three) additional vessels also requiring reconstruction (renal or mesenteric arteries). At 3.2 years (1-6 years) of follow-up, all patients are doing well. CONCLUSIONS: The TESLA procedure allows surgical correction of MAS without the need for prosthetic grafts in young children who are still growing.

Effects of Mechanical Complications on Radiation Exposure During Fluoroscopically Guided Gastrojejunostomy Exchange in the Pediatric Population.

The purpose of the article is to evaluate the effects of mechanical complications, such as clogging or coiling, of gastrojejunostomy tubes on radiation exposure during exchange in the pediatric population. In this HIPAA-compliant and IRB-approved study, we retrospectively reviewed procedural records for patients undergoing gastrojejunostomy (GJ) tube exchange during a 4-month period in 2014. Success of the procedure, specifications of the tube, age, and sex of the patient as well as radiation exposure during the procedure were included. Radiation exposure was measured in fluoroscopy time and cumulative air kerma. Complications encountered during exchange were also recorded, if available. Patients presenting for gastrostomy to GJ conversions or combined procedures were excluded from the study. Ordinary and mixed effect linear regression models were used to test associations between GJ tube parameters, presence of mechanical complications, and fluoroscopy time and radiation dose. 146 patients undergoing 285 GJ exchanges met inclusion criteria over the 4-month study period (M:F 82:64). All exchanges were successful with 85 demonstrating a form of mechanical complication (44 coiled, 41 clogged). Of the reported GJ tube specifications, only tube length was significantly associated with mechanical complications (p < 0.001). The presence of mechanical complication was significantly associated with increased radiation exposure and fluoroscopy time (p < 0.0001). Mechanical complications of gastrojejunostomy tubes, such as clogging or coiling, are associated with increased radiation exposure during exchange. Strategies to decrease these complications, including re-siting the gastrostomy tract or placement of a surgical jejunostomy in the event of repeated coiling of a tube should be strongly considered.

Catheter-Directed Thrombolysis in a Child with Bilateral Renal Artery Graft Thrombosis.

A 5-year-old boy with midaortic syndrome who had undergone aortic bypass and bilateral renal artery grafts presented to the emergency department 1 year after surgery with symptoms of nausea, vomiting, and abdominal pain. Because of delay in diagnosis of bilateral renal artery thrombosis, his condition progressed to anuric renal failure. He underwent catheter-directed thrombolysis 7 days after presentation with administration of tissue plasminogen activator and heparin infusion over a 24-hour period. There was successful resolution of thrombus and complete recovery of renal function to baseline. The patient had normal renal function at 6-month follow-up.

Imaging features of kaposiform lymphangiomatosis.

BACKGROUND: Kaposiform lymphangiomatosis is a rare, aggressive lymphatic disorder. The imaging and presenting features of kaposiform lymphangiomatosis can overlap with those of central conducting lymphatic anomaly and generalized lymphatic anomaly. OBJECTIVE: To analyze the imaging findings of kaposiform lymphangiomatosis disorder and highlight features most suggestive of this diagnosis. MATERIALS AND METHODS: We retrospectively identified and characterized 20 children and young adults with histopathological diagnosis of kaposiform lymphangiomatosis and radiologic imaging referred to the vascular anomalies center between 1995 and 2015. RESULTS: The median age at onset was 6.5 years (range 3 months to 27 years). The most common presenting features were respiratory compromise (dyspnea, cough, chest pain; 55.5%), swelling/mass (25%), bleeding (15%) and fracture (5%). The thoracic cavity was involved in all patients; all patients had mediastinal involvement followed by lung parenchymal disease (90%) and pleural (85%) and pericardial (50%) effusions. The most common extra-thoracic sites of disease were the retroperitoneum (80%), bone (60%), abdominal viscera (55%) and muscles (45%). There was characteristic enhancing and infiltrative soft-tissue thickening in the mediastinum and retroperitoneum extending along the lymphatic distribution. CONCLUSION: Kaposiform lymphangiomatosis has overlapping imaging features with central conducting lymphatic anomaly and generalized lymphatic anomaly. Presence of mediastinal or retroperitoneal enhancing and infiltrative soft-tissue disease along the lymphatic distribution, hemorrhagic effusions and moderate thrombocytopenia (50-100,000/µl) should favor diagnosis of kaposiform lymphangiomatosis.

Percutaneous coil embolization of massive pelvic pseudoaneurysm in an infant.

Iatrogenic pseudoaneurysm formation is an uncommon but potentially serious complication of cardiac catheterization. This case report describes diagnosis and treatment of a large left external iliac artery pseudoaneurysm in a 3-month-old boy following cardiac catheterization and aortic balloon dilatation for aortic coarctation. A 4-cm pulsatile mass in the left hemipelvis was discovered on MRI performed 6 weeks later for possible tethered spinal cord. Sonography and angiography showed a large pseudoaneurysm of the left external iliac artery just distal to the iliac bifurcation with no flow in the external iliac artery distal to the pseudoaneurysm. Percutaneous US-guided thrombin injection was performed twice, with partial recanalization after each treatment. The residual portion of the pseudoaneurysm was then successfully embolized with percutaneous coils deployed under US and fluoroscopic guidance.

Kaposiform lymphangiomatosis: a distinct aggressive lymphatic anomaly.

OBJECTIVE: To describe the clinical and imaging characteristics of a new lymphatic disorder with a unique histological pattern and poor prognosis. STUDY DESIGN: An observational, retrospective study identified and characterized 20 patients with distinct lymphatic histopathology referred to the Vascular Anomalies Center at Boston Children's Hospital between 1995 and 2011. RESULTS: The median age at onset was 6.5 years (range, birth to 44 years). Clinical and radiologic findings suggested a generalized process. The most common presentations were respiratory symptoms (50%), hemostatic abnormalities (50%), and an enlarging, palpable mass (35%). All patients had mediastinal involvement; 19 patients developed pericardial (70%) and/or pleural effusions (85%). Extrathoracic disease manifested in bone and spleen and less frequently in abdominal viscera, peritoneum, integument, and extremities. Despite aggressive procedural and medical therapies, the 5-year survival was 51% and the overall survival was 34%. Mean interval between diagnosis and death was 2.75 years (range, 1-6.5 years). CONCLUSIONS: We describe a clinicopathologically distinct lymphatic anomaly. We propose the term kaposiform lymphangiomatosis (KLA) because of characteristic clusters or sheets of spindled lymphatic endothelial cells accompanying malformed lymphatic channels. The intrathoracic component is most commonly implicated in morbidity and mortality; however, extrathoracic disease is frequent, indicating that KLA is not restricted to pulmonary lymphatics. The mortality rate of KLA is high despite aggressive multimodal therapy.

Intramuscular capillary-type hemangioma: radiologic-pathologic correlation.

BACKGROUND: Infantile hemangiomas demonstrate a pattern of proliferative growth in infancy followed by a slow phase of involution. In contrast a rare type of vascular tumor, intramuscular capillary-type hemangioma, usually presents beyond the period of infancy with nonspecific symptoms and no evidence of involution. OBJECTIVE: The purpose of this study was to characterize the clinical, imaging, histopathological characteristics and management of intramuscular capillary-type hemangioma. MATERIALS AND METHODS: We performed a retrospective review of a 20-year period to identify children diagnosed with intramuscular capillary-type hemangioma. Patient demographics, imaging and histopathological findings were recorded. RESULTS: We included 18 children (10 boys, 8 girls) with histologically proven intramuscular capillary-type hemangioma - and adequate imaging. The mean age at presentation was 8.1 years (range 1 day to 19 years). Twelve lesions involved muscles of the extremities, 4 were located in the trunk and 2 were in the head and neck. MRI had been performed in all children and demonstrated a soft-tissue mass with flow voids, consistent with fast flow. The lesion was well-circumscribed in 16 children and intralesional fat was seen in 14. Doppler US demonstrated a heterogeneous lesion, predominantly isoechoic to surrounding muscle, with enlarged arterial feeders. Enlarged feeding arteries, inhomogeneous blush and lack of arteriovenous shunting were noted on angiography (n = 5). The most common histopathological findings were lobules of capillaries with plump endothelium and at least some adipose tissue. The lesions were excised in six children. Two children were lost to follow-up. In the remaining 10, follow-up MRI studies ranging from 3 months to 10 years showed that the lesion enlarged in proportion to the child (n = 7), demonstrated slow growth (n = 2) or remained stable (n = 1). There was no change in imaging characteristics on follow-up. CONCLUSION: Intramuscular capillary-type hemangioma is a rare benign vascular tumor of skeletal muscle. The most typical imaging features show a heterogeneous intramuscular mass with fast flow, and intralesional fat. Although the lesion is relatively stable in appearance over time, imaging does not obviate the need for a biopsy to rule out sarcoma. The diagnosis can usually be established by typical findings on histopathology.

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.

Fibro-adipose vascular anomaly: clinical-radiologic-pathologic features of a newly delineated disorder of the extremity.

BACKGROUND: The diagnosis and management of vascular anomalies of the extremities can be challenging as these disorders are uncommon and may clinically overlap. The aim of this paper is to describe the clinical, radiologic, and histopathologic features of fibro-adipose vascular anomaly (FAVA), a previously unrecognized disorder of the limb. METHODS: The clinical, imaging, operative, and histopathologic data from patients with a unique intramuscular lesion of the extremities comprising dense fibrofatty tissue and slow-flow vascular malformations were retrospectively reviewed. RESULTS: Sixteen patients diagnosed with FAVA of the extremity (3 male and 13 female individuals) met the clinical, radiologic, and histopathologic inclusion criteria. The age at presentation ranged from the time of birth to 28 years. The locations of the lesions were: calf (n=10), forearm/wrist (n=3), and thigh (n=3). Fourteen patients presented with severe pain. Seven of the patients with calf lesions had limited ankle dorsiflexion. On imaging, the complex intramuscular lesions replaced muscle fibers with fibrofatty overgrowth and phlebectasia (dilation of the veins). The extrafascial component comprised fatty overgrowth, phlebectasia, and an occasional lymphatic malformation. The histopathologic features comprised dense fibrous tissue, fat, and lymphoplasmacytic aggregates within atrophied skeletal muscle. Adipose tissue also infiltrated skeletal muscle at the periphery of the lesion. There were large, irregular, and sometimes excessively muscularized venous channels and smaller, clustered channels. Other findings include organizing thrombi, a lymphatic component, and dense fibrous tissue-encircled nerves. CONCLUSIONS: The constellation of clinical, radiologic, and histopathologic features constitutes a distinct entity comprising fibrofatty infiltration of muscle, unusual phlebectasia with pain, and contracture of the affected extremity. The clinical and radiologic findings permit the diagnosis of FAVA with major therapeutic implications. LEVEL OF EVIDENCE: Level III.

Image-Guided Transrectal Drainage of Pelvic Abscesses in Children.

OBJECTIVE: To describe our technique and share our experience with image-guided transrectal drainage (TRD) of pelvic abscesses in children. MATERIALS AND METHODS: Retrospective review and analysis of indications for image-guided TRD and examination of procedural outcomes in pediatric patients with pelvic abscesses over 8 years. RESULTS: A total of 69 patients (33 males and 36 females) with symptomatic pelvic abscesses underwent image-guided TRD. The median age and weight of the patients were 11.5 years (range, 3-18) and 46.8 kg (range, 15.1-118.0), respectively. The etiologies of the pelvic abscesses were perforated appendicitis (72.5%) and post-operative collections (27.5%). All patients presented with abdominal pain. Fever, emesis, and diarrhea were also common symptoms. The size of the pelvic abscesses ranged from 24.0 to 937.1 mL (median, 132.7). Technical success was achieved in 68 of 69 TRD procedures (98.6%). Clinical improvement was observed in all patients with technically successful TRD. The TRD catheter dwell time ranged from 0 to 10 days (median, 4.0). Most patients who underwent TRD for perforated appendicitis subsequently underwent elective appendectomy after the resolution of the pelvic abscess (84.0%). The median time from TRD to elective appendectomy was 2.8 months (range, 0.3-6.1). There were no procedure-related complications. CONCLUSION: Image-guided TRD is a safe and effective procedure with high technical and clinical success rates for the treatment of pelvic abscesses in children.