Hisham Dahmoush, MBChB

Abstract

Epidermal nevus syndrome (ENS) represents a diverse group of rare neurocutaneous diseases associated with the presence of characteristic epidermal nevi (EN) in the skin and extracutaneous manifestations in the eyes, skeletal, urogenital and central nervous systems. We present a case series of 7 children with ENS, with specific attention to the neuroradiological characteristics of this entity.

View details for DOI 10.21037/qims-20-634

View details for PubMedID 33392041

Abstract

The increase in understanding of molecular biology and recent advances in genetic testing have caused rapid growth in knowledge of genetic causes of malformations of cortical development. Imaging diagnosis of malformations of cortical development can be made prenatally in a large subset of fetuses based on the presence of specific deviations from the normal pattern of development, characteristic imaging features, and associated non-central-nervous-system (CNS) abnormalities. In this review the authors discuss the role of four key cell molecules/molecular pathways in corticogenesis that are frequently implicated in complex prenatally diagnosed malformations of cortical development. The authors also list the currently described genes causing defects in these molecules/molecular pathways when mutated, and the constellation of imaging findings resultant of such defects.

View details for DOI 10.1007/s00247-020-04674-5

View details for PubMedID 33252763

Abstract

Diagnosing musculoskeletal pathology requires understanding of the normal embryological development. Intrinsic errors of skeletal development are individually rare but are of paramount clinical importance because anomalies can greatly impact patients' lives. An accurate assessment of the fetal musculoskeletal system must be performed to provide optimal genetic counseling as well as to drive therapeutic management. This manuscript reviews the embryology of skeletal development and the appearance of the maturing musculoskeletal system on fetal MRI. In addition, it presents a comprehensive review of musculoskeletal fetal pathology along with postnatal imaging.

View details for DOI 10.1007/s00247-020-04769-z

View details for PubMedID 33252766

View details for Web of Science ID 000475965900397

Abstract

Understanding the underlying pathophysiology and the patterns of disease spread is crucial in accurate image interpretation. In this pictorial review, the common and important inflammatory processes of the temporal bone in children will be discussed, and key computed tomography (CT) and magnetic resonance imaging (MRI) features described.Inflammatory processes are categorized by anatomical location: the petrous apex and the inner, middle and outer ear. A complete review of the literature is provided.Cholesteatoma, cholesterol granuloma and mucoceles are inflammatory processes that occur across the anatomical subsites of the temporal bone, whilst site-specific inflammatory processes include labyrinthitis ossificans in the inner ear and keratosis obturans in the external ear. Infection is a key cause of inflammation in the temporal bone, and specific infections include petrous apicitis, otitis media and necrotizing otitis externa. Finally, important mimics and do-not-touch lesions are considered. CT and MRI are complementary in assessing these disorders, as two of the most important diagnostic clues are the presence of bone erosion, best appreciated on CT, and true diffusion restriction as seen on MRI. Flow charts to assist in the diagnosis of paediatric temporal bone inflammatory disease are also provided.Paediatric temporal bone inflammatory processes are common and can have severe clinical sequelae. Timely intervention, facilitated by correct radiological diagnosis, can often prevent progression of disease, loss of hearing and systemic illness.

View details for DOI 10.1007/s00234-019-02258-1

View details for PubMedID 31321462

Abstract

Saposin A is a post-translation product of the prosaposin (PSAP) gene that serves as an activator protein of the galactocerebrosidase (GALC) enzyme, and is necessary for the degradation of certain glycosphingolipids. Deficiency of saposin A leads to a clinical picture identical to that of early-infantile Krabbe disease caused by GALC enzyme deficiency. Galactosylsphingosine, also known as psychosine, is a substrate of the GALC enzyme that is known to be elevated in classic Krabbe disease. We present the case of an 18-month-old male with clinical and radiological findings concerning for Krabbe disease who had preserved GALC enzyme activity and negative GALC gene sequencing, but was found to have a homozygous variant, c.257T>A (p.I86N), in the saposin A peptide of PSAP. Psychosine determination on dried blood spot at 18months of age was elevated to 12nmol/L (normal <3nmol/L). We present this case to add to the literature on the rare diagnosis of atypical Krabbe disease due to saposin A deficiency, to report a novel presumed pathogenic variant within PSAP, and to suggest that individuals with saposin A deficiency may have elevated levels of psychosine, similar to children with classic Krabbe disease due to GALC deficiency.

View details for DOI 10.1016/j.ymgme.2019.08.001

View details for PubMedID 31439510

View details for DOI 10.1148/rg.2019180084

View details for Web of Science ID 000455091000015

Abstract

Infants and children under 2 years of age are at greatest risk for devastating neurologic complications following nonaccidental trauma. While a subdural hematoma (SDH) is the most common finding and is often enough to raise suspicion for abuse, no single injury is pathognomonic for abusive head trauma (AHT). Rather, the combination of imaging and physical findings and the clinical presentation help confirm the diagnosis of AHT. Familiarity with the spectrum of findings and proper identification of the imaging abnormalities is important for the radiologist to facilitate treatment and removal of the patient from the abusive environment. Injury is usually a result of shaking, which includes hyperflexion, hyperextension, and rotational forces, and less commonly impact trauma or a combination of both. Key anatomic features unique to the infant's head, neck, and spine and associated biomechanical forces are responsible for entities such as hypoxic ischemic injury, bridging vein thrombosis, SDH, parenchymal lacerations, and spinal and retinal injuries. Although the association of subpial hemorrhage with AHT has not been investigated, it warrants attention in very young infants who endure accidental or inflicted trauma. A combination of CT of the head and MRI of the brain and cervical spine aids in the accurate diagnosis, appropriate management, and subsequent protection of these patients. RSNA, 2018.

View details for PubMedID 30468627

View details for DOI 10.1016/j.clinimag.2018.04.012

View details for Web of Science ID 000437818900040

Abstract

Lobular capillary hemangiomas are acquired benign vascular neoplasms which typically affect the skin and mucous membranes. While these lesions commonly involve the head and neck, particularly the oral cavity, there are no reports in the literature of lobular capillary hemangioma arising from the mandible. The diagnosis of such a rare entity can therefore be challenging, especially as it may mimic more aggressive lesions, including malignancy. We present a rare case of an 8-year-old male with a lobular capillary hemangioma of the mandible, highlighting its imaging features and discussing the differential diagnosis of primary mandibular lesions in the pediatric population.

View details for PubMedID 29704808

Abstract

Pretransplant functional imaging (FI), particularly a negative positron emission tomography (PET), is a strong predictor of outcome in adults with relapsed or refractory Hodgkin lymphoma (HL), but data in pediatrics are limited.The medical records of 49 consecutive pediatric patients, who received autologous transplant at a single institution, were retrospectively analyzed. All patients had either gallium or PET scan before transplant and were conditioned with carmustine, etoposide, cytarabine, and melphalan (BEAM). Deauville scores were retrospectively assigned for patients with PET (score 4 positive).Of the 49 patients (median age, 16.2 years), 41 (84%) were pretransplant FI negative and eight (16%) were pretransplant FI positive, after first- to fourth-line salvage therapy, and a median of two salvage cycles. Eighteen patients (37%) received posttransplant radiation. At a median follow up of 46 months, 45 patients (92%) were alive and disease free, and there were three nonrelapse deaths and only one relapse death (Deauville score of 5). The 4-year progression-free survival (PFS) for the entire cohort was 92% (95% confidence interval [CI]: 78-97), and PFS based on pretransplant disease status was 95% (95% CI: 82-99%) in the negative FI group versus 75% (95% CI: 31-93) if positive FI (P = 0.057).Our analysis revealed outstanding outcomes for children and adolescents with relapsed/refractory HL. There were too few relapses to identify the predictive value of pretransplant metabolic status, but pediatric patients with relapsed/refractory HL and a negative pretransplant FI had excellent survival.

View details for DOI 10.1002/pbc.26707

View details for PubMedID 28696028

View details for DOI 10.1002/pbc.26707

View details for Web of Science ID 000416119400004

Abstract

Massive ovarian edema is a rare benign condition that predominantly affects childbearing women as well as preadolescent girls. It is thought to result from intermittent or partial torsion of the ovary compromising the venous and lymphatic drainage but with preserved arterial supply. The clinical features of massive ovarian edema are nonspecific and can simulate tumors, leading to unnecessary oophorectomy.To demonstrate imaging features that should alert radiologists to consider the diagnosis of massive ovarian edema preoperatively so that fertility-sparing surgery may be considered.We identified five girls diagnosed with massive ovarian edema at pathology. Presenting symptoms, sidedness, imaging appearance, preoperative diagnosis, and operative and histopathological findings were reviewed.Age range was 9.6-14.3years (mean age: 12.5years). Common imaging findings included ovarian enlargement with edema of the stroma, peripherally placed follicles, isointense signal on T1-W MRI and markedly hyperintense signal on T2-W MRI, preservation of color Doppler flow by US, and CT Hounsfield units below 40. The uterus was deviated to the affected side in all patients. Two of the five patients had small to moderate amounts of free pelvic fluid. Mean ovarian volume on imaging was 560mL (range: 108-1,361mL).While the clinical presentation of massive ovarian edema is nonspecific, an enlarged ovary with stromal edema, peripherally placed follicles and preservation of blood flow may be suggestive and wedge biopsy should be considered intraoperatively to avoid unnecessary removal of the ovary.

View details for DOI 10.1007/s00247-017-3782-4

View details for PubMedID 28246900