Current Utilization of Electron Microscopy in the Pediatric Pathology Setting: A Survey by the SPP Practice Committee.

BACKGROUND: Electron microscopy (EM), once an important component in diagnosing pediatric diseases, has experienced a decline in its use. To assess the impact of this, pediatric pathology practices were surveyed regarding EM services. METHODS: The Society of Pediatric Pathology Practice Committee surveyed 113 society members from 74 hospitals. Settings included 36 academic tertiary, 32 free-standing children's, and 6 community hospitals. RESULTS: Over 60% maintained in-house EM services and had more than 2 pathologists interpreting EM while reporting a shortage of EM technologists. Freestanding children's hospitals had the most specimens (100-200 per year) and more diverse specimen types. Hospitals with fewer than 50 yearly specimens often used reference laboratories. Seventeen had terminated all in-house EM services. Challenges included decreasing caseloads due to alternative diagnostic methods, high operating costs, and shortages of EM technologists and EM-proficient pathologists. Kidney, liver, cilia, heart, and muscle biopsies most often required EM. Lung/bronchoalveolar lavage, tumor, skin, gastrointestinal, nerve, platelet, and autopsy samples less commonly needed EM. CONCLUSIONS: The survey revealed challenges in maintaining EM services but demonstrated its sustained value in pediatric pathology. Pediatric pathologists may need to address the centralization of services and training to preserve EM diagnostic proficiency among pathologists who perform ultrastructural interpretations.

Pediatric Low-Grade Spindle Cell Neoplasm With A Novel AK5::ALK Fusion: A Case Report.

OBJECTIVES: Spindle cell neoplasms (SCN) share a single commonality of spindle-shaped cells on histopathology but are diverse in etiology. Expanding our collective knowledge of these neoplasms could further research in targeted therapies. We present a case of pediatric cutaneous SCN with a novel etiology, and the methods used to identify its origination. CASE PRESENTATION AND RESULTS: A 1.5-year-old child presented with a 7-month history of a rapidly enlarging, erythematous, non-painful scalp mass without ulceration or bleeding. The child underwent ultrasound and magnetic resonance imaging, revealing a 2.9 × 3 × 2 cm vascular mass without intracranial connections. The mass was successfully resected at surgery. Subsequent histopathologic and genetic testing indicated a SCN harboring a previously undescribed gene rearrangement between adenylate kinase 5 (AK5) and anaplastic lymphoma kinase (ALK). The patient received close clinical follow-up and at 6 months post-surgery had no recurrent disease. CONCLUSIONS: ALK rearrangements are common amongst many tumor types, but to our knowledge, AK5::ALK rearrangement has never been reported in SCN. Considering the rapid development of targeted clinical therapies, including those targeting ALK activity, this finding could be significant in the treatment of future patients with similar clinicopathologic and genetic presentation.

Massive Post-traumatic Femoral Cyst Resulting in Pathologic Fracture in a Child: A Case Report.

CASE: A 10-year-old boy experienced a pathologic diaphyseal femur fracture through a large cyst encompassing 40% of femoral length. At age 5, he had had a traumatic ipsilateral diaphyseal femur fracture, treated with flexible nailing. Biopsy at age 10 revealed a simple bone cyst with components of aneurysmal bone cyst. Curettage, antegrade nailing, and allograft resulted in successful osseous healing. CONCLUSION: Post-traumatic cysts of long bones are rare and have not been reported to cause pathologic fracture in children. This case highlights that close scrutiny of follow-up radiographs of long bone fractures may identify clinically important post-traumatic cysts.

Clinical and Histopathologic Predictors of Disaccharidase Deficiency in Duodenal Biopsy Specimens.

OBJECTIVES: Disaccharidase (DS) activity in duodenal biopsy specimens is the gold standard for diagnosing DS deficiency. We investigated strategies to reduce the need for DS testing and whether clinical or histopathologic factors predict DS deficiency. METHODS: A retrospective chart review analyzed 1,678 DS results in children, biopsy indication(s), and duodenal histopathology. RESULTS: One or more DSs were abnormal in 42.8%. Sufficient lactase predicted sucrase, palatinase, and maltase sufficiency (negative predictive value 97.7%). Three patients had sucrase-isomaltase deficiency (0.2%). DS deficiency was more common in biopsy specimens for positive celiac serology (78.0%). Villous blunting, intraepithelial lymphocytosis, and active inflammation predicted DS deficiency; a combination of any two had an 81.4% positive predictive value. CONCLUSIONS: Utilization could be reduced by only testing cases with normal duodenal histopathology and ongoing clinical suspicion for DS deficiency after reviewing pathology. In cases with suspected celiac disease and/or mucosal injury, DS deficiency is common and likely secondary, limiting test utility.

Minimally Invasive Adenocarcinoma of the Lung as Second Malignant Neoplasm Following Pediatric Rhabdomyosarcoma.

Primary pulmonary tumors are extremely rare in the pediatric population; however, sporadic cases of invasive pulmonary adenocarcinoma as a second malignant neoplasm (SMN) have been described in survivors of pediatric cancers. Pediatric patients with rhabdomyosarcoma (RMS) have a particularly increased risk of developing a SMN when compared to the general population, though pulmonary adenocarcinoma has not been previously described in a RMS patient. A 12-year-old female previously treated for stage IV pelvic RMS was found to have a left pulmonary nodule on surveillance computed tomography. The nodule was detected 4.25 years after the completion of treatment, which included resection, chemotherapy, and radiation to the abdomen and pelvis. Wedge resection of the pulmonary lesion was performed with negative margins. Histopathological examination revealed minimally invasive adenocarcinoma. Pulmonary adenocarcinoma may rarely present as a SMN in pediatric cancer survivors. The pathogenesis of this association is not yet entirely clear, but may include chemotherapy-induced mutagenesis and/or genetic predisposition. As pulmonary adenocarcinoma may present as a lung lesion radiographically indistinguishable from metastatic RMS, it should be considered in the differential diagnosis of any pediatric RMS survivor presenting with a new pulmonary nodule, especially in cases with late recurrence.

Iatrogenic injury and unexpected hospital death in the newborn.

Neonates are unusually vulnerable to iatrogenic injury due to small body size, delicate tissues, and immature immune systems. Investigation of an unexpected neonatal death in the hospital should begin with a review of the medical record and discussion with medical staff involved in the patient׳s care. Postmortem investigation should include a complete and well-documented autopsy. Additional investigations, such as microbiological studies and chemical and toxicological studies of postmortem and antemortem fluid samples, may be crucial in arriving at a diagnosis. Causes of iatrogenic injury include birth trauma, medication errors and adverse drug effects, hospital-acquired infection, and medical device malfunction, incorrect placement, and misuse. Autopsy is an important tool for understanding the cause of an unexpected death, improving the quality of care, and providing closure to parents and family.

Unexpected coronary artery findings in mucopolysaccharidosis. Report of four cases and literature review.

INTRODUCTION: The mucopolysaccharidosis syndromes are a group of lethal inherited disorders affecting multiple organ systems by the progressive deposition of glycosaminoglycan. Advances in treatment such as enzyme replacement and hematopoietic stem cell transplantation have significantly improved the outcome of these disorders. An in-depth understanding of the pathophysiology of heart disease in these disorders is essential since death from cardiac causes continues to be common. Epicardial coronary artery luminal narrowing from myointimal proliferation and glycosaminoglycan deposition is well described in severe mucopolysaccharidosis type I [Hurler syndrome, mucopolysaccharide IH] but poorly understood in other "non-Hurler" phenotypes of these disorders. Given the rarity of these conditions, autopsy specimens are uncommon. METHODS: Tissue from epicardial coronary arteries from autopsies of four patients with non-Hurler mucopolysaccharidosis (attenuated type I, type IIIA, type IIIC, and type VI) who had died after hematopoietic cell transplantation (within 1 month in three cases; after 5 years in the fourth) was examined by light microscopy. RESULTS: Unexpectedly, near-normal coronary arteries were observed in the patient with attenuated mucopolysaccharidosis type I, while the coronaries from patients with type IIIA, IIIC, and VI demonstrated classic histologic features of glycosaminoglycan deposition. The most severe findings were found in the MPS IIIC patient who had 5 years of full donor engraftment after transplantation. CONCLUSIONS: Our current understanding of the cardiac manifestations of the mucopolysaccharidoses fails to explain why near-normal coronary arteries may be observed when abnormalities would be most likely to be expected and, conversely, why significant histopathology is present when it would be least expected. Identification of downstream effects of glycosaminoglycan deposition may identify other metabolites or metabolic pathways that are important in the clinicopathologic manifestations of these diseases. SUMMARY: The mucopolysaccharidosis diseases are a group of inherited disorders affecting multiple organ systems by the progressive deposition of glycosaminoglycan. Severe coronary artery disease is well recognized in severe type I mucopolysaccharidosis (Hurler syndrome), but unexpected coronary artery disease occurs in other, "non-Hurler" mucopolysaccharidoses. Factors responsible for the development of coronary pathology in the mucopolysaccharidoses remain elusive.

Familial LCAT deficiency in a child with nephrotic syndrome.

BACKGROUND: Lecitin cholesterol acyltransferase (LCAT) deficiency comprises a group of rare disorders related to HDL metabolism. These disorders are characterized by ophthalmologic, hematologic, and renal findings. Case diagnosis/treatment: A 15-year-old female who presented with nephrotic syndrome and hypertension was diagnosed with LCAT deficiency by renal biopsy and LCAT enzyme activity. Her edema and hypertension improved with diuretic and antihypertensive therapies. Continued care of her LCAT deficiency is ongoing. CONCLUSION: Although rare, LCAT deficiency should be in the differential diagnosis of nephrotic syndrome in the setting of abnormally low HDL cholesterol levels.

Sustained remission of severe Multicentric Castleman disease following multiagent chemotherapy and tocilizumab maintenance.

Castleman disease is a rare lymphoproliferative disorder, which presents in a unicentric or multicentric fashion. Multicentric Castleman disease (MCD) is associated with significant systemic symptoms, in part related to the underlying role of interleukin-6 in disease pathogenesis. Treatment for MCD has not been well established and prognosis has historically been poor. We present a case of severe MCD in a pediatric patient who has shown sustained remission following multi-agent chemotherapy and targeted maintenance therapy with the interleukin-6 receptor inhibitor, tocilizumab. This represents the first case report of sustained remission of MCD in a pediatric patient following discontinuation of tocilizumab therapy.

Perigestational dietary folic acid deficiency protects against medulloblastoma formation in a mouse model of nevoid basal cell carcinoma syndrome.

Hereditary nevoid basal cell carcinoma syndrome (NBCCS) is caused by PTCH1 gene mutations that result in diverse neoplasms including medulloblastoma (MB). Epidemiological studies report reduced pediatric brain tumor risks associated with maternal intake of prenatal vitamins containing folic acid (FA) and FA supplements specifically. We hypothesized that low maternal FA intake during the perigestational period would increase MB incidence in a transgenic NBCCS mouse model, which carries an autosomal dominant mutation in the Ptch1 gene. Female wild-type C57BL/6 mice (n = 126) were randomized to 1 of 3 diets with differing FA amounts: 0.3 mg/kg (low), 2.0 mg/kg (control), and 8.0 mg/kg (high) 1 mo prior to mating with Ptch1 (+/-) C57BL/6 males. Females were maintained on the diet until pup weaning; the pups were then aged for tumor development. Compared to the control group, offspring MB incidence was significantly lower in the low FA group (Hazard Ratio = 0.47; 95% confidence interval 0.27-0.80) at 1 yr. No significant difference in incidence was observed between the control and high FA groups. Low maternal perigestational FA levels may decrease MB incidence in mice genetically predisposed to tumor development. Our results could have implications for prenatal FA intake recommendations in the presence of cancer syndromes.

Successful management of factor IX inhibitor-associated nephrotic syndrome in a hemophilia B patient.

BACKGROUND: Nephrotic syndrome (NS) is a recognized complication of immune tolerance induction (ITI) therapy, a treatment strategy used to treat inhibitors in patients with hemophilia B receiving factor IX concentrate. CASE DIAGNOSIS/TREATMENT: We present a 4-year-old boy with hemophilia B and an inhibitor who underwent ITI, and developed NS 19 months into this therapy. A percutaneous renal biopsy was safely performed with factor IX (FIX) concentrate administration both preceding and following the procedure. The patient's inhibitor level had increased to 1.4-1.6 Bethesda Units just prior to the onset of proteinuria. Histology confirmed segmental membranous nephropathy (MGN). The patient was continued on FIX concentrate as ITI and also received 4 weekly doses of rituximab and ongoing immunosuppression with mycophenolate mofetil. This resulted in the complete resolution of his inhibitor and his NS. He continues with a modified ITI regimen and remains inhibitor-free without proteinuria >12 months post-biopsy. CONCLUSIONS: Hemophilia B patients undergoing ITI should be regularly screened for NS. At first detection of proteinuria, with proper precautions, a percutaneous kidney biopsy can be performed safely in patients with low levels of inhibitor. Our patient had segmental MGN with complete remission of NS.

Long-term use of ventricular assist device as a bridge to recovery in acute fulminant myocarditis.

We report the successful long-term use of a left ventricular assist device (Berlin EXCOR) as a bridge to recovery in a patient with fulminant parvovirus B19 myocarditis. The use of this device allowed time for myocardial recovery, avoiding the need for cardiac transplantation.

Unusual presentations of BK virus infections in pediatric renal transplant recipients.

BKV has emerged as a significant pathogen in the field of transplantation, predominantly causing BKV nephropathy in renal transplant recipients and hemorrhagic cystitis in HSCT recipients. However, case reports describe more diverse complications, and we too present three unusual cases of BKV infections in pediatric renal transplant recipients. First, we describe a case of biopsy-proven renal damage secondary to BKV prior to the onset of viremia, demonstrating that BKV nephropathy can occur without preceding viremia. We also present two renal transplant recipients with persistent BK viruria, one with BKV-associated hemorrhagic cystitis and the other with microscopic hematuria. Therefore, we conclude that BKV manifestations may be more diverse than previously thought and suggest clinical utility in urine BKV qPCR testing in specific transplant recipients.

Oral alveolar soft part sarcoma in childhood and adolescence: report of two cases and review of literature.

Alveolar soft part sarcoma (ASPS) constitutes a rare soft tissue malignant neoplasm comprising less than 1 % of all soft tissue sarcomas. ASPS demonstrates a strong predilection for adolescents and young adults, with a female predominance reported. The head and neck region is the most commonly affected region in pediatric patients with the tongue and orbit affected most commonly. Herein we present the clinical, radiographic, histopathologic, immunohistochemical and molecular features of two examples of ASPS affecting the oral cavity of 4 and 13 year-old boys, along with a focused review of the literature on intraoral ASPS in pediatric patients.

A case series of genital vascular anomalies in children and their management: lessons learned.

OBJECTIVE: To review our experience with genital vascular anomalies and discuss the management considerations for patients with associated genitourinary defects. METHODS: We reviewed the presentation, course, management considerations, surgical treatment, and follow-up of all cases of genital vascular anomalies treated at a single institution from January 2008 to October 2011. The lesions were classified according to the International Society for the Study of Vascular Anomalies. All patients were boys <18 years old. RESULTS: We identified 3 patients with genital vascular anomalies. Of these 3 patients, 2 had an infantile hemangioma and 1 had a venous malformation. All lesions were identifiable on physical examination, and 2 of the patients presented within a few months of birth. One patient had associated genitourinary abnormalities that complicated his treatment. Scrotal ultrasonography and pelvic magnetic resonance imaging consistently showed the vascular anomalies to be highly vascular and distinct from the underlying testes. Both intrascrotal lesions were excised, and the cutaneous lesion was excised as a part of a larger genitourinary reconstruction. At a mean follow-up of 33 months (range 23-42), the intrascrotal infantile hemangioma had recurred, requiring repeat intervention, but the cutaneous hemangioma had not. CONCLUSION: Vascular anomalies of the male genitalia are rare. Pelvic magnetic resonance imaging is useful for characterizing the internal extent of vascular anomalies and ultrasonography is useful in monitoring these lesions over time. The timing of surgery and the high recurrence rate are important considerations when planning surgical resection of genital vascular anomalies, especially when associated with concomitant genitourinary defects.

Reassessing the clinical significance of chorionic membrane microcysts and linear necrosis.

Recent studies have suggested that 2 lesions of the fetal membranes, linear necrosis at the choriodecidual junction and chorionic membrane microcysts, are markers of uteroplacental ischemia. To evaluate this hypothesis, we examined 807 placentas from unselected, consecutive deliveries at a single hospital over approximately 6 months with specific recording of the presence of chorionic microcysts or linear membrane necrosis. Clinical factors that might indicate uteroplacental ischemia were abstracted from the pathology report, including small for gestational age, pregnancy-induced hypertension, meconium macrophages in the membranes, infarctions, and small placenta. We found that both chorionic microcysts and linear membrane necrosis are very common lesions in unselected placentas, involving 28% and 18% of all placentas, respectively. There was no correlation between the presence of chorionic membrane microcysts and any marker of uteroplacental ischemia. Linear necrosis correlated only with the presence of meconium macrophages. We conclude that these membrane changes are not a useful marker of ischemia in an unselected population of placentas. We suggest caution in the interpretation of these findings, to avoid overdiagnosing ischemia or other pathologic processes.

Symmetrical peripheral gangrene in four pediatric cardiac surgery patients receiving extracorporeal membrane oxygenation.

Symmetrical peripheral gangrene (multilimb ischemia without large artery occlusion) is a rare condition usually associated with disseminated intravascular coagulation, hemodynamic compromise, and/or sepsis. However, it has not been described in patients on extracorporal membrane oxygenation (ECMO). Over a 5 year period, four pediatric patients developed symmetrical peripheral gangrene on ECMO after cardiac surgery. They subsequently died and came to autopsy. History, physical examination, and laboratory studies were examined. Gross and microscopic autopsy material was reviewed. Patients were 11 days to 13 years old. Extracorporal membrane oxygenation duration was 11-22 days, and limb ischemia began 2-4 days before death. Three patients had rapid onset, with ischemia developing in <48 hours. In the fourth, ischemic changes began as focal lesions and gradually spread. Two patients were septic. Three had evidence of other end-organ damage. Pressors were used in 3 patients before the limb ischemia. Autopsies disclosed ischemic changes involving all limbs, with confluent ecchymoses. In a detailed examination in 1 case, large arteries of the extremities were patent. Involved skin and soft tissue showed bland fibrin thrombi in the microcirculation, with tissue necrosis and hemorrhage. This report describes the first 4 cases of symmetrical peripheral gangrene complicating ECMO. The 4 pediatric patients all had recent surgery for congenital cardiac disease, and all had significant exposure to ECMO prior to developing limb ischemia. Symmetrical peripheral gangrene is an unusual complication of ECMO that may arise in the setting of disseminated intravascular coagulation, sepsis, or other hemostatic and/or hemodynamic imbalance.

Metastatic neuroblastoma presenting as a scrotal mass in an infant.

OBJECTIVE: Neuroblastoma is a common malignancy of infancy and childhood. The scrotum and paratesticular tissues are rare sites of presentation. We report the case of an infant who presented with a scrotal mass that proved to be a metastatic neuroblastoma. PATIENT AND RESULTS: A previously healthy 4-month-old boy presented with a scrotal mass. Ultrasound and surgery showed a well circumscribed, 1.2-cm nodule in the inferior scrotum, associated with dartos fascia. Intraoperative frozen section revealed a small round blue cell tumor, prompting a wider excision. Final diagnosis was poorly differentiated neuroblastoma with unfavorable histology. Further imaging revealed a large adrenal mass, with hepatic and pleural metastases. CONCLUSION: Metastatic and primary neuroblastomas are rare causes of scrotal mass in infants and children. Treatment and prognosis depend on factors including patient age, histology and stage. Stem-cell-supported chemotherapy is the current treatment of choice for high-stage, high-risk neuroblastoma, as in this case. The differential diagnosis of pediatric scrotal neoplasms is broad, and several small round blue cell tumors can present in the scrotum and paratesticular tissues. Preoperative ultrasound of the scrotum and abdomen may assist in diagnosis and surgical planning. Intraoperative frozen section may assist in diagnosis and tissue triage.

Calretinin immunohistochemistry versus acetylcholinesterase histochemistry in the evaluation of suction rectal biopsies for Hirschsprung Disease.

Diagnosis of Hirschsprung disease (HSCR) relies on histologic and/or histochemical staining of sections from suction rectal biopsies. Acetylcholinesterase histochemistry (AChE) facilitates diagnosis but is not universally employed, in part because it requires special tissue handling. Calretinin immunohistochemistry (IHC) may be a useful alternative, because loss of calretinin immunoreactive nerves reportedly correlates spatially with aganglionosis. We investigated the patterns of calretinin IHC in suction rectal biopsies from HSCR and non-HSCR patients and compared the diagnostic value of calretinin IHC with a widely used rapid AChE method. In suction rectal biopsies that contain ganglion cells, small nerves in the lamina propria, muscularis mucosae, and superficial submucosa contain granular aggregates of calretinin immunoreactivity. Immunolabeling of these nerves is completely absent in the aganglionic biopsies of HSCR patients. Multiple observers independently reviewed calretinin IHC and AChE sections of suction rectal biopsies from 14 HSCR patients and 17 non-HSCR controls. Five observers, blinded to the correct diagnosis, scored each patient's calretinin IHC and AChE slides as HSCR, not HSCR, or equivocal. The frequencies of major and minor discrepant diagnoses were compared. Calretinin IHC yielded no misdiagnoses or major discrepancies between observers. In contrast, 2 misdiagnoses and significantly more interobserver disagreement resulted from the AChE-stained sections. Calretinin IHC appears to be a reasonable, and potentially superior, alternative to AChE as an adjunctive diagnostic method for evaluating suction rectal biopsies for HSCR.