Yolk sac tumours of the orbit and sinonasal tract.

PURPOSE: The aim of this study is to report two cases of paediatric Yolk sac tumours (YST) of the orbit and sinonasal tract, with a major review on the subject. METHODS: Two case reports along with a comprehensive retrospective literature review of all English language publications between 1974 and 2021 is presented. Literature review examined the demographics, clinical presentation and diagnostic and prognostic factors of extragonadal YSTs of the orbit and sinonasal tract. RESULTS: Orbit and sinuses are rare sites for YST, with only 25 paediatric cases reported in the literature. Extragonadal yolk sac tumours carry a significantly worse outcome than those localised to the gonads, with the 5-year survival of 66% and 81-89%, respectively. Our review found the median age of presentation to be 18 months (18 months for males and 24 months for females), and females are more commonly affected. The most common presentations were proptosis, facial swelling and ophthalmoplegia. Treatments and therefore outcomes varied in the cases due to the large time period. Of the cases reported in the last 10 years, all patients with data provided were alive and disease-free at follow-up. CONCLUSION: Sino-orbital yolk sac tumours are rare and have variable presentations, dependent on the extent of local invasion. Early diagnosis and treatment with multimodal therapy are paramount in having improved overall survival.

Recurrent BCOR Internal Tandem Duplication and YWHAE-NUTM2B Fusions in Soft Tissue Undifferentiated Round Cell Sarcoma of Infancy: Overlapping Genetic Features With Clear Cell Sarcoma of Kidney.

Soft tissue undifferentiated round cell sarcoma (URCS) occurring in infants is a heterogenous group of tumors, often lacking known genetic abnormalities. On the basis of a t(10;17;14) karyotype in a pelvic URCS of a 4-month-old boy showing similar breakpoints with clear cell sarcoma of kidney (CCSK), we have investigated the possibility of shared genetic abnormalities in CCSK and soft tissue URCS. Most CCSKs are characterized by BCOR exon 16 internal tandem duplications (ITDs), whereas a smaller subset shows YWHAE-NUTM2B/E fusions. Because of overlapping clinicopathologic features, we have also investigated these genetic alterations in the so-called primitive myxoid mesenchymal tumor of infancy (PMMTI). Among the 22 infantile URCSs and 7 PMMTIs selected, RNA sequencing was performed in 5 and 2 cases, with frozen tissue, respectively. The remaining cases with archival material were tested for YWHAE-NUTM2B/E by fluorescence in situ hybridization (FISH) or reverse transcription-polymerase chain reaction (RT-PCR), and BCOR ITD by PCR. A control group of 4 CCSKs and 14 URCSs in older children or adults without known gene fusion and 20 other sarcomas with similar histomorphology or age at presentation were also tested. A YWHAE-NUTM2B fusion was confirmed in the index case by FISH and RT-PCR, whereas BCOR ITD was lacking. An identical YWHAE-NUTM2B fusion was found in another URCS case of a 5-month-old girl with a back lesion. The remaining cases and control group lacked YWHAE gene rearrangements; instead, consistent BCOR ITDs, similar to CCSK, were found in 15/29 (52%) infantile sarcoma cases (9/22 infantile URCS and 6/7 PMMTI). In the control cohort, BCOR ITD was found only in 3 CCSK cases but not in the other sarcomas. Histologically, URCS with both genotypes and PMMTI shared significant histologic overlap, with uniform small blue round cells with fine chromatin and indistinct nucleoli. A prominent capillary network similar to CCSK, rosette structures, and varying degree of myxoid change were occasionally seen. BCOR ITD-positive tumors occurred preferentially in the somatic soft tissue of the trunk, abdomen, and head and neck, sparing the extremities. RNAseq showed high BCOR mRNA levels in BCOR ITD-positive cases, compared with other URCSs. In summary, we report recurrent BCOR exon 16 ITD and YWHAE-NUTM2B fusions in half of infantile soft tissue URCS and most PMMTI cases, but not in other pediatric sarcomas. These findings suggest a significant overlap between infantile URCS and CCSK, such as age at presentation, histologic features, and genetic signature, thus raising the possibility of a soft tissue counterpart to CCSK.

The correlation between time to skin grafting and hypertrophic scarring following an acute contact burn in a porcine model.

One sequelae of burn injury remains the development of hypertrophic scarring. This appears more likely when the healing has been prolonged. Early excision of deep dermal burns and subsequent split skin grafting (SSG) may provide a more favorable result. The optimal timing of grafting for deeper dermal burns remains controversial. This study sought to establish evidence for the optimal grafting time using a porcine model. Five Large White female pigs were exposed to four contact burn injuries for duration of 20 seconds at 92°C. Each site was randomized to a treatment arm: dressing only as the control, SSG day 3, SSG day 14, and SSG day 21. Burn wound biopsies were obtained at days 0, 3, 14, 21, and 99 after the burn injury, together with microbiological swabs. Digital photographs were taken to assess scarring using the Vancouver scar scale. All biopsies were subject to histological and immunohistochemical analysis. Vancouver scar scale scores and histopathological analysis indicated that areas grafted on day 3 had the least fibrosis and scarring (P = 0.031). There was a strong correlation between the histological evaluation of the degree of fibrosis and α-smooth muscle actin levels (r = .60, P = .014). A greater degree of fibrosis was observed in the presence of infection (P = .028). Sites grafted on day 3 consistently exhibited the best clinical and histological scar outcome. The increased fibrosis observed in delayed grafting may have been be related to progression of burn depth and infection. These results suggest that early grafting of deep dermal burns may be preferential.

Early cyst growth is associated with the increased nuclear expression of cyclin D1/Rb protein in an autosomal-recessive polycystic kidney disease rat model.

BACKGROUND: In this study we hypothesised that proliferation, and the increased expression of G(1)-phase cyclins (D1, E) and phosphorylated retinoblastoma protein (p-Rb) is restricted to the early period of synchronized cyst growth in autosomal-recessive polycystic kidney disease (ARPKD). METHODS: Lewis polycystic kidney disease (lpk) rats (model of ARPKD; postnatal weeks 1, 3, 6, 12 and 24; n = 6 each) as well as human juvenile cystic renal disease tissue (n = 2) were examined. RESULTS: Between weeks 1 and 3, the percentage cyst area increased 6-fold in lpk rats, followed by a more progressive rise (1.5-fold increase) until week 24. The number of Ki-67-, cyclin D1- and p-Rb-positive cells increased in lpk rats and peaked at week 3, declining thereafter. By serial sections, cysts co-expressed Ki-67, cyclin D1 and p-Rb. The expression of cyclin E was variable, and peaked at week 24. In human tissue, small cysts had a higher expression of p-Rb. CONCLUSION: Proliferation and the increased nuclear expression of cyclin D1 and p-Rb coincide with the early phase of cyst growth in rats and humans, suggesting that there might be a therapeutic window in which cyclin-dependent kinase inhibitors are most effective in preventing kidney enlargement in ARPKD.

Sexually dimorphic patterns of episomal rAAV genome persistence in the adult mouse liver and correlation with hepatocellular proliferation.

Recombinant adeno-associated virus vectors (rAAVs) show exceptional promise for liver-targeted gene therapy, with phenotype correction in small and large animal disease models being reported with increasing frequency. Success in humans, however, remains a considerable challenge that demands greater understanding of host-vector interactions, notably those governing the efficiency of initial gene transfer and subsequent long-term persistence of gene expression. In this study, we examined long-term enhanced green fluorescent protein (eGFP) expression and vector genome persistence in the mouse liver after rAAV2/8-mediated gene transfer in early adulthood. Two intriguing findings emerged of considerable scientific and clinical interest. First, adult female and male mice showed distinctly different patterns of persistence of eGFP expression across the hepatic lobule after exhibiting similar patterns initially. Female mice retained a predominantly perivenous pattern of expression, whereas male mice underwent inversion of this pattern with preferential loss of perivenous expression and relative retention of periportal expression. Second, these changing patterns of expression correlated with sexually dimorphic patterns of genome persistence that appear linked both spatially and temporally to underlying hepatocellular proliferation. Observation of the equivalent phenomenon in man could have significant implications for the long-term therapeutic efficacy of rAAV-mediated gene transfer, particularly in the context of correction of liver functions showing metabolic zonation.

Primary cutaneous lymphoblastic lymphoma in children: series of eight cases with review of the literature.

AIM: Primary cutaneous lymphoblastic lymphoma is a rare but well recognised tumour predominantly of childhood. In this study we examine eight cases of cutaneous lymphoblastic lymphoma in children, which is the largest series to date of tumours confined to the skin with or without local lymph nodes (stage I or II) but without systemic disease at diagnosis. METHODS: The clinical history and histology from the eight cases were reviewed together with a panel of immunohistochemical stains to confirm lineage and diagnosis. RESULTS: Seven of the eight cases were confirmed as B-lymphoblastic lymphoma (B-LBL) of the skin, with the eighth case representing a CD4+/CD56+ plasmacytoid dendritic cell tumour. The cases were all stage I or II, and all patients received systemic chemotherapy after full staging investigations to exclude systemic disease at diagnosis. All patients remained in complete remission at the time of last follow-up of between 3 and 9 years from diagnosis. CONCLUSIONS: Lymphoblastic lymphoma may present primarily in the skin without systemic manifestation, with the majority of such cases representing B-LBL. A rare case of childhood CD4+/CD56+ plasmacytoid dendritic cell tumour with similar blastic morphology is also described. Full staging investigations are mandatory at diagnosis to exclude systemic disease. Cases confined to stage I or II at diagnosis carry an excellent prognosis with appropriate systemic chemotherapeutic treatment.

Autopsy findings in a series of five cases of fetomaternal haemorrhages.

AIMS: Fetal blood cells enter the maternal circulation in up to 95% of pregnancies, but usually in minute volumes. Haemodynamically significant fetomaternal haemorrhage (FMH) is a much rarer event reported in approximately 1 in 2800 pregnancies. Most of the literature on this phenomenon emphasises the clinical aspects, and there is no comprehensive description of the autopsy findings. We present a series of five fatal FMH. The aim of this series is to highlight some of the autopsy findings that may prompt consideration of a diagnosis of FMH and lead to appropriate confirmatory testing and counselling of the affected couple. METHODS: The five cases were referred to the Children's Hospital at Westmead for full autopsy. A Kleihauer-Betke test was performed on the mother's blood within one week of delivery in each case. RESULTS: The infants ranged in age from 27 to 40 weeks gestation (mean 36.6 weeks) with a mean birth weight of 2793 g. The estimated volumes of fetal blood lost ranged from 443 to 104 mL (mean loss 243 mL). The estimated percentage of fetal blood volume loss was an average of 107% (i.e., greater than the entire blood volume of the fetus). No other causes of hydrops were identified. Pallor was often noted, and in most cases the autopsies were markedly bloodless with large vessels collapsed. Where the brain:liver ratio could be applied, two fetuses showed a mild increase in ratio, while one infant showed moderate growth restriction with a ratio of 6.2:1 (normal ratio 2.8:1 on non-macerated fetuses over 28 weeks gestation). Placental abnormalities included thrombosis of the umbilical vein and intervillous 'haematomas' in two cases. The most striking microscopic feature was the presence of intravascular nucleated RBC within virtually all organs. Placental intervillous (i.e., within the maternal vascular compartment) nucleated red blood cells were also seen in all cases. CONCLUSIONS: The autopsy findings of FMH can be subtle and easily overlooked unless a high index of suspicion is maintained. The most reliable autopsy features are pallor, subcutaneous oedema or serous effusions, and intravascular nucleated red blood cells (RBC) in organs or more specifically in the placental intervillous space. In all cases of unexplained fetal death a Kleihauer-Betke test should be performed.