Adamantinoma-Like Ewing Sarcoma of the Mandible Evaluated on 18F-FDG PET/CT.

ABSTRACT: Ewing sarcoma is the second most common primary bone tumor in children. Typical Ewing sarcoma most frequently occurs in long bones and within the pelvis. ALES (adamantinoma-like Ewing sarcoma) is a rare subtype of Ewing sarcoma that is characterized by epithelial differentiation in addition to small round blue cells. Unlike typical Ewing sarcoma, ALES has been described in several cases in the head and neck. Herein, we describe a case of a 9-year-old boy with ALES of the mandible evaluated on 18F-FDG PET/CT with correlative MRI scans.

Asymptomatic macrocephaly: to scan or not to scan.

BACKGROUND: Macrocephaly is a common finding in infants and is often idiopathic or familial. In the absence of clinical signs and symptoms, it can be difficult to determine when concern for underlying pathology is justified. OBJECTIVES: The objectives of this study were to determine the utility of screening head ultrasound (US) in asymptomatic infants with macrocephaly and to identify clinical factors associated with significant US findings. MATERIALS AND METHODS: A 20-year retrospective review was performed of infants undergoing head US for macrocephaly or rapidly increasing head circumference. Data collected included age, gender, head circumference at birth and at the time of US, specialty of the ordering physician, US findings, computed tomography (CT) or magnetic resonance imaging (MRI) findings, and clinical course including interventions. RESULTS: Four hundred and forty infants met inclusion criteria. Two hundred and eighty studies (64%) were found to be normal, 137 (31%) had incidental findings, 17 (3.8%) had indeterminate but potentially significant findings, and 6 (1.4%) had significant findings. Twenty of the 23 infants with indeterminate or significant findings had subsequent CT or MRI. This confirmed significant findings in eight infants (1.8%): three subdural hematomas, two intracranial tumors, two aqueductal stenoses, and one middle fossa cyst. Five of the eight infants required surgical procedures. The only statistically significant association found with having a significant finding on head US was head circumference at birth. CONCLUSION: Ultrasound is a useful initial study to evaluate infantile macrocephaly, identifying several treatable causes in our study and, when negative, effectively excluding significant pathology.

PET Imaging of a Unique Case of Multiple Myeloma in an Adolescent.

Pediatric solitary plasmacytomas are extremely rare, with only 14 cases previously reported. None of these reports included PET imaging findings. We present PET/CT and PET/MRI imaging findings in a 15-year-old boy with what was initially thought to be a solitary plasmacytoma, which later developed into multiple myeloma. The initial PET/CT of solitary plasmacytoma, as well as postradiotherapy PET/MRI findings with the new lesions suggestive of multiple myeloma, are presented.

Pediatric applications of Dotatate: early diagnostic and therapeutic experience.

In recent years, new somatostatin receptor agents (SSTRs) have become available for diagnostic imaging and therapy in neuroendocrine tumors. The novel SSTR ligand DOTA-DPhel-Tyr3-octreotate (Dotatate) in particular can be linked with 68Gallium for diagnostic imaging purposes, and with the ß-emitter 177Lutetium for radiotherapy in the setting of neuroendocrine tumors. Dotatate imaging offers distinct advantages in the evaluation of neuroendocrine tumors compared to standard techniques, including greater target-to-background ratio and lesion conspicuity, high sensitivity/specificity, improved spatial resolution with positron emission tomography (PET)/CT or PET/MR, and decreased radiation exposure. Although currently off-label in pediatrics, Dotatate theranostics in children are being explored, most notably in the setting of neuroblastoma and hereditary neuroendocrine syndromes. This article provides a multicenter case series of Dotatate imaging and therapy in pediatric patients in order to highlight the spectrum of potential clinical applications.

Mesenchymal Hamartoma in Children: A Diagnostic Challenge.

Mesenchymal hamartoma is a benign tumor of the liver with a poorly understood pathogenesis. It is uncommon in older children, especially after 2 years of age. The signs and symptoms may be nonspecific; therefore, a high index of suspicion is required for diagnosis and treatment. We report a 5-year-old previously healthy male who presented with acute abdominal pain, fatigue, and fever. He was diagnosed with pneumonia initially and treated with antibiotics. A computed tomography (CT) scan done for evaluation of his persistent abdominal pain demonstrated a hepatic mass. Follow-up magnetic resonance imaging (MRI) of the liver demonstrated multiple serpiginous tubular-type structures, read as possible Caroli syndrome. He had a normal abdominal examination and normal biochemistries including alanine aminotransferase, aspartate aminotransferase, gamma-glutamyl transferase, alkaline phosphatase, and alpha-fetoprotein. He was referred to our institution for second opinion. On further review of his imaging studies, the lesion was thought to be a mesenchymal hamartoma. He subsequently underwent resection of the mass. Pathology confirmed the diagnosis of mesenchymal hamartoma.

18F-FDG PET/CT Equivalent of the Hepatic Hot Spot Sign With CT Correlation.

A 43-year-old woman presented with an FDG-avid mediastinal Ewing sarcoma invading and nearly occluding the superior vena cava. Geographic increased FDG uptake in hepatic segment IVA was the only other site of nonphysiologic FDG activity. This focal activity was without an underlying mass, had atypical morphology for a hepatic metastasis, and correlated well with prior CT findings of abnormal segment IVA enhancement resulting from the recruitment of portocaval collaterals. In the correct setting, the F-FDG hepatic hot spot should be considered in the differential of a focal FDG-avid hepatic lesion in segment IVA.

Nuss bar migrations: occurrence and classification.

BACKGROUND: Pectus excavatum results from dorsal deviation of the sternum causing narrowing of the anterior-posterior diameter of the chest. It can result in significant cosmetic deformities and cardiopulmonary compromise if severe. The Nuss procedure is a minimally invasive technique that involves placing a thin horizontally oriented metal bar below the dorsal sternal apex for correction of the pectus deformity. OBJECTIVE: To identify the frequency and types of Nuss bar migrations, to present a new categorization of bar migrations, and to present examples of true migrations and pseudomigrations. MATERIALS AND METHODS: We retrospectively reviewed the electronic medical records and all pertinent radiologic studies of 311 pediatric patients who underwent a Nuss procedure. We evaluated the frequency and type of bar migrations. RESULTS: Bar migration was demonstrated in 23 of 311 patients (7%) and occurred within a mean period of 26 days after surgery. Bar migrations were subjectively defined as deviation of the bar from the position demonstrated on the immediate postoperative radiographs and categorized as superior, inferior, rotation, lateral or flipped using a new classification system. Sixteen of the 23 migrations required re-operation. CONCLUSION: Nuss bar migration can be diagnosed with careful evaluation of serial radiographs. Nuss bar migration has a wide variety of appearances and requires exclusion of pseudomigration resulting from changes in patient positioning between radiologic examinations.

¹¹C-Choline PET/CT in Recurrent Prostate Cancer and Nonprostatic Neoplastic Processes.

Choline positron emission tomography (PET)/computed tomography (CT), with both carbon 11 ((11)C) choline and fluorine 18 ((18)F) choline, is an increasingly used tool in the evaluation of patients with biochemically recurrent prostate cancer. It has allowed detection and localization of locally recurrent and metastatic lesions that were difficult or impossible to identify using more conventional modalities. Many of the patients followed for their prostate cancer are elderly and have a higher rate of nonprostate cancer lesions or malignancies. As our experience with choline PET/CT has grown, it has become apparent that many of these nonprostate cancer processes, both benign and malignant, can be detected. Invasive thymoma, renal cell carcinoma, papillary thyroid carcinoma, and parathyroid adenoma are a few of the processes that have been incidentally detected with (11)C-choline PET/CT at our institution and have significantly altered subsequent clinical management of the patient. Although most of the secondary lesions are detected due to their increased (11)C-choline avidity, several have been detected due to their decreased or lack of avidity in the background of a highly avid organ. For instance, large liver masses that are relatively non-choline-avid create large activity defects in the otherwise highly active liver. Familiarity with normal (11)C-choline physiologic activity, the most common prostate metastatic patterns, and imaging characteristics of secondary lesions is essential for the detection and correct diagnosis of such lesions so that proper follow-up and management can be recommended.

A novel sclerosing skeletal dysplasia with mixed sclerosing bone dysplasia, characteristic syndromic features, and clinical and radiographic evidence of male-male transmission.

We report on a father and his 4-year-old son sharing a characteristic dysmorphic facial phenotype (including hyperteleroism, prominent forehead, and wide nasal bridge), macrocephaly, hearing loss, palatal clefting, developmental delay, hypotonia and bony abnormalities including marked cranial sclerosis and sclerosis of the ribs and long bones, which evolved in severity in the son between the ages of 2 and 4 years. The father's radiographs also showed prominent coarse striations, patchy metaphyseal sclerotic plaques, markedly increased bone density and cortical thickening of long bones, and significant degenerative changes in the thoracic spine. The son has an additional history of sleep apnea resulting from multi-level airway obstruction that includes adenoid hypertrophy, lingual tonsil hypertrophy, subglottic stenosis, and supra-arytenoid tissue consistent with laryngomalacia and tracheomalacia. The clinical, radiographic, and genetic findings in father and son are consistent with a sclerosing skeletal dysplasia syndrome with similarities to mixed sclerosing bone dysplasia (MSBD) including metaphyseal plaques, osteopathia striata, and cranial sclerosis (OS-CS). This family may represent one of the first descriptions of familial inheritance and evolving phenotype in MSBD. The evidence for male-male transmission would support the existence of an autosomal mechanism of inheritance for a novel form of MSBD with characteristic syndromic features.

Pediatric MR elastography of hepatic fibrosis: principles, technique and early clinical experience.

Numerous pediatric conditions result in hepatic fibrosis. As treatments develop for the underlying disorders, a non-invasive assessment of liver fibrosis would be beneficial as an adjunct or possible replacement for the traditional gold standard, liver biopsy. Magnetic resonance elastography is a noninvasive imaging technique that has been used successfully in adults for identification and assessment of liver fibrosis. This review describes the basic principles of MR elastography as well as the technical aspects specific to children. Clinical pediatric applications, limitations and areas for future research are described.

Pediatric eosinophilic esophagitis: radiologic findings with pathologic correlation.

BACKGROUND: Eosinophilic esophagitis is increasingly recognized as a cause of dysphagia or food impaction in pediatric patients. It has a high male predominance and is often associated with a history of allergy or asthma. OBJECTIVE: To correlate fluoroscopic findings in eosinophilic esophagitis with the endoscopic and histologic findings. MATERIALS AND METHODS: We retrospectively reviewed the upper gastrointestinal (UGI) findings of eosinophilic esophagitis and correlated them with the clinical, endoscopic and histologic findings in a series of 17 children (12 boys, 5 girls). RESULTS: UGI findings were normal in 12 children, including 4 who had a normal UGI exam after endoscopic disimpaction for an obstructing food bolus. Five children had strictures identified on UGI: one was demonstrated with endoscopy. This suggests that the impactions and strictures were due to an esophageal dysmotility rather than a fixed anatomic abnormality. CONCLUSION: Because the UGI findings are frequently normal in eosinophilic esophagitis, radiologists need to have a high index of suspicion for this disease. In children with a strong clinical history, especially impaction in the absence of an esophageal stricture, endoscopy and biopsy are indicated for further evaluation.

PET/CT of fibrodysplasia ossificans progressiva.

Fibrodysplasia ossificans progressiva (FOP) is an exceedingly rare genetic disorder of connective tissue characterized by extensive and irreversible heterotopic ossification of soft-tissue masses that develop in response to inflammation or trauma. Successful management relies on preventative measures and avoidance of invasive procedures such as intramuscular injections and biopsies. Early diagnosis can prevent extensive heterotopic ossification and is possible with recognition of the classic clinical findings in the feet in association with rapidly evolving soft-tissue masses of the trunk and extremities. Unfortunately, in 87% of the 269 previously reported cases, the diagnosis was not considered initially. Patients are often subjected to biopsy of the soft-tissue masses. The pathology of the fibrodysplasia ossificans progressiva is often confused with sarcoma. These patients might be imaged with PET as part of a standard oncological work-up. We present the first reported PET/CT images of a patient with FOP in order to alert radiologists to this diagnostic pathway. Awareness of the disorder might prevent further unnecessary interventions that can lead to extensive deformity and suffering.

Isolated fallopian tube torsion: sonographic and CT features.

BACKGROUND: Isolated fallopian tube torsion (IFTT) rarely occurs in pediatric patients and is difficult to diagnose preoperatively. OBJECTIVE: To determine the common sonographic and CT findings in girls with IFTT. MATERIALS AND METHODS: We retrospectively reviewed the hospital charts and imaging studies of the eight girls diagnosed with and treated for IFTT at Columbus Children's Hospital between January 1995 and June 2006 whose final diagnosis was IFTT. RESULTS: The mean age was 13 years with a range of 12 to 15 years. Two girls were premenarcheal. The most common presenting symptom was acute pelvic pain (n = 5). All patients were imaged. Six girls were imaged first with US, and the most common finding was a complex cystic pelvic mass in the midline (n = 5) and normal uterus and ovaries. Three of the eight girls had imaging with CT. In two girls, the torsed tube could be identified. In 63% of the girls, the uterus was deviated toward the side of torsion. The correct preoperative diagnosis was made in only one girl. None of the torsed fallopian tubes was salvaged at surgery. Pathological findings included ipsilateral adnexal cysts associated with the torsed tube (n = 7). CONCLUSION: IFTT should be considered in the differential diagnosis for perimenarcheal girls who present with acute pelvic pain and who demonstrate a cystic mass in a midline position (either in the cul-de-sac or superior to the uterus) associated with a normal ipsilateral ovary.

Pulmonary hyalinizing granuloma and retroperitoneal fibrosis in an adolescent.

We describe a 15-year-old boy who developed pulmonary hyalinizing granuloma (PHG) and retroperitoneal fibrosis (RPF). His PHG and RPF were not associated with histoplasmosis or tuberculosis and appeared to represent idiopathic autoimmune phenomena. This is the first reported case of PHG in a pediatric patient and the fourth reported co-occurrence of PHG and RPF. The use of F-18 fluorodeoxyglucose positron emission tomography in the diagnostic and follow-up evaluation of PHG is reported.

Coincidence FDG-PET in the evaluation of Langerhans' cell histiocytosis: preliminary findings.

BACKGROUND: Bone involvement in Langerhans' cell histiocytosis (LCH) is common. Both bone scintigraphy and plain films are used to identify osseous lesions, but lack specificity for disease activity and response to therapy. FDG-PET is a sensitive technique for identifying bone lesions when histiocytes are present. OBJECTIVE. To describe the potential of coincidence FDG-PET (cFDG-PET) for identification of active bone lesions in LCH and to determine whether it can provide more specific information regarding lesional response to therapy than bone scintigraphy or radiography. MATERIALS AND METHODS: The clinical data and imaging findings of three patients with osseous lesions of LCH were retrospectively reviewed. RESULTS: cFDG-PET identified all active LCH osseous lesions in these patients, differentiated active from healed lesions, and demonstrated normalization of uptake in a treated lesion earlier than bone scintigraphy and radiography. CONCLUSION: cFDG-PET appears to have greater specificity than bone scintigraphy and radiography for the identification of active osseous lesions in LCH. It also may predict response to treatment earlier than conventional techniques. Its use in the evaluation of LCH warrants further study.