Small Neuroendocrine Tumors of the Whole Gastrointestinal Tract Performed Endoscopic or Surgical Resections Also Show Positive for Lymphovascular Invasion

<b><i>Background and Aims:</i></b> In gastrointestinal neuroendocrine tumors (GI-NETs), tumor size and grading based on cellular proliferative ability indicate biological malignancy but not necessarily clinically efficient prognostic stratification. We analyzed tumor size- and grading-based prevalence of lymphovascular invasion in GI-NETs to establish whether these are true biological malignancy indicators. <b><i>Methods:</i></b> We included 155 cases (165 lesions), diagnosed histologically with GI-NETs, that had undergone endoscopic or surgical resection. Patient age, sex, method of treatment, tumor size, invasion depth, lymphovascular invasion positivity according to Ki-67 index-based neuroendocrine tumor grading, distant metastases, and outcome were evaluated. The primary endpoints were the prevalence of lymphovascular invasion according to tumor size and grading. <b><i>Results:</i></b> Overall, 24.8% were positive for lymphovascular invasion. There was a high rate of lymphovascular invasion positivity even among grade 1 cases (22.8%). The rate of lymphovascular invasion was 3.4% for grade 1 cases &#x3c;5 mm, with a lymphovascular invasion rate of 8.7% for those 5–10 mm. Lymphovascular invasion ≤10% required a tumor size ≤8 mm, and lymphovascular invasion ≤5% required a tumor size ≤6 mm. A cutoff of 6 mm was identified, which yielded a sensitivity of 79% and a specificity of 63%. Even small GI-NETs grade 1 of the whole GI tract also showed positive for lymphovascular invasion. <b><i>Conclusions:</i></b> GI-NETs ≤10 mm had a lymphovascular invasion prevalence exceeding 10%. The lymphovascular invasion impact in GI-NET development is incompletely understood, but careful follow-up, including consideration of additional surgical resection, is crucial in cases with lymphovascular invasion.

Opsanus beta (Goode & Bean, 1880) (Acanthopterygii: Batrachoididae), a non-indigenous toadfish in Sepetiba Bay, south-eastern Brazil

The introduction of non-native predator fish is thought to have important negative effects on native prey populations. Opsanus beta is a non-native toadfish that was originally described in the Gulf of Mexico, between the west coast of Florida and Belize. In the present study, we describe, for the first time, the occurrence of O. beta in Sepetiba Bay (22°55′S), south-eastern Brazil, probably brought into the bay through ships' ballast water. Thirteen specimens were recorded in this area near to Sepetiba Port. Similarly, three other records of this species in the Brazilian coast were also reported near to port areas at Rio de Janeiro (22°49′S), Santos (23°59′S) and Paranaguá (25°33′S) ports. To confirm the species identity, we employed DNA barcoding and compared our samples with sequences deposited on public databases, which indicated that our samples are highly similar (>99.9% of genetic similarity) to O. beta samples collected near its type locality. Several individuals were found in the capable spawning phase, according to histological analysis of the reproductive cell stages. The environmental plasticity of this species and the favourable local environmental conditions probably enabled the establishment of O. beta in this region. This raises concerns of potential high invasion impact due to this species' diet and reproductive capacity.

The application of selected invasion frameworks to urban ecosystems

Urbanization is a major driver of global change. Profound human-mediated changes to urban environments have provided increased opportunities for species to invade. The desire to understand and manage biological invasions has led to an upsurge in frameworks describing the mechanisms underpinning the invasion process and the ecological and socio-economic impacts of invading taxa. This paper assesses the applicability of three commonly used invasion frameworks to urban ecosystems. The first framework describes the mechanisms leading to invasion; the second and third frameworks assess individual species, and their associated environmental and socio-economic impacts, respectively. In urban areas, the relative effectiveness of the barriers to invasion is diminished (to varying degrees) allowing a greater proportion of species to move through each subsequent invasion stage, i.e. “the urban effect” on invasion. Impact classification schemes inadequately circumscribe the full suite of impacts (negative and positive) associated with invasions in urban areas. We suggest ways of modifying these frameworks to improve their applicability to understanding and managing urban invasions.