M J Kim

BACKGROUND: The aim of this study was to identify clinical predictors of malignancy and surgical strategies for pancreatic solid pseudopapillary neoplasm (SPN) by analysis of surgical outcomes at a single institution. METHODS: All patients who underwent surgery for SPN between 1995 and 2010 were identified. Histopathology slides of all patients were reviewed by a specialized pathologist and the neoplasms were classified according to the criteria of the World Health Organization 2010. RESULTS: Of the 106 patients identified, 85 (80·2 per cent) were female, and the median age was 36 (range 10-65) years. Median tumour size was 4·5 (range 1·0-15·0) cm. Some 17 patients (16·0 per cent) were classified as having a high-grade malignant SPN. Tumour size of at least 5 cm was associated with high-grade malignant potential (P = 0·022). Although lymph nodes were removed from 40 patients (37·7 per cent), there were no nodal metastases. A total of five patients underwent en bloc resection of adjacent structures, including two with portal vein involvement. After a median follow-up of 56·9 months, two patients with high-grade malignant SPN had evidence of tumour recurrence in the lymph nodes and liver. CONCLUSION: SPN with a diameter of 5 cm or more is associated with a high-grade malignant phenotype. Complete surgical removal is associated with low recurrence rates.

SUMMARY Lithophyllum Philippi (Corallinales, Corallinophycidae, Rhodophyta) is a diverse genus of non‐geniculate coralline algae. Lithophyllum neo‐okamurae and L. okamurae are commonly found in the intertidal and subtidal zones of Jeju Island, Korea, where they contribute to local benthic communities. Despite their ecological importance, their morpho‐anatomical and genetic variation remain poorly understood in this region. We investigated these two species through morpho‐anatomical and molecular analyses ( psb A and rbc L) based on specimens collected from 13 sites around Jeju, Korea. Lithophyllum neo‐okamurae exhibited both unattached, free‐living (rhodolith) and attached forms, each showing distinct distributions associated with local hydrodynamic and substrate conditions. Molecular analyses revealed distinct haplotypes corresponding to the two forms, and morpho‐anatomical analyses detected statistically significant differences in tetrasporangial conceptacle chamber dimensions (diameter and height) between them. In contrast, L. okamurae occurred exclusively as unattached rhodoliths and was mainly distributed in deeper subtidal rhodolith beds compared with L. neo‐okamurae . Our findings demonstrate form‐related morpho‐anatomical and genetic differentiation in L. neo‐okamurae and underscore the ecological role of L. neo‐okamurae and L. okamurae as major rhodolith‐forming species in Jeju, Korea.

Abstract Lithophyllum is a highly diverse and widely distributed genus of non-geniculate coralline algae. Despite its ecological importance, a comprehensive taxonomic treatment of Lithophyllum species in Korea remains lacking, primarily due to substantial unresolved cryptic diversity within the genus. In this study, we describe Lithophyllum jejuensis based on an integrated taxonomic approach combining molecular phylogenetic analyses with detailed morpho-anatomical observations of specimens from Korea. Phylogenetic analyses of plastid markers ( psb A and rbc L) resolved L. jejuensis as a distinct lineage. Morpho-anatomically, the species exhibits a multilayered, encrusting growth form with successive applanate branches, bistratose margins, and predominantly palisade basal (hypothallial) cells. Lithophyllum jejuensis resembles L. prototypum (originally described from the U.S. Virgin Islands), but differs from the holotype in having widely triangular tetrasporangial conceptacle pore canals that taper toward the thallus surface. Additionally, L . jejuensis can be distinguished from Korean L. neo-okamurae and L. okamurae by an exclusively adherent, encrusting growth form with applanate branches, bistratose margins composed of palisade cells, and larger tetrasporangial conceptacle chamber dimensions. These results reaffirm the importance of integrative taxonomy in elucidating the cryptic diversity of Korean Lithophyllum .