Dermatological manifestations in Noonan syndrome: a prospective multicentric study of 129 patients positive for mutation

BACKGROUND

Data on dermatological manifestations of Noonan syndrome (NS) remain heterogeneous and are based on limited dermatological expertise.

OBJECTIVES

To describe the dermatological manifestations of NS, compare them with the literature findings, and test for dermatological phenotype-genotype correlations with or without the presence of PTPN11 mutations.

METHODS

We performed a large 4-year, prospective, multicentric, collaborative dermatological and genetic study.

RESULTS

Overall, 129 patients with NS were enrolled, including 65 patients with PTPN11-NS, 34 patients with PTPN11-NS with multiple lentigines (NSML), and 30 patients with NS who had a mutation other than PTPN11. Easy bruising was the most frequent dermatological finding in PTPN11-NS, present in 53·8% of patients. Multiple lentigines and café-au-lait macules (n ≥ 3) were present in 94% and 80% of cases of NSML linked to specific mutations of PTPN11, respectively. Atypical forms of NSML could be associated with NS with RAF1 or NRAS mutations. In univariate analysis, patients without a PTPN11 mutation showed (i) a significantly higher frequency of keratinization disorders (P = 0·001), including keratosis pilaris (P = 0·005), ulerythema ophryogenes (P = 0·0001) and palmar and/or plantar hyperkeratosis (P = 0·06, trend association), and (ii) a significantly higher frequency of scarce scalp hair (P = 0·035) and scarce or absent eyelashes (P = 0·06, trend association) than those with PTPN11 mutations.

CONCLUSIONS

The cutaneous phenotype of NS with a PTPN11 mutation is generally mild and nonspecific, whereas the absence of a PTPN11 mutation is associated with a high frequency of keratinization disorders and hair abnormalities.

Functional ultrastructure and cytochemistry of vitellogenesis and mature vitellocytes of the digenean Cainocreadium labracis (Dujardin, 1845), parasite of Dicentrarchus labrax (L., 1758)

Vitellogenesis and vitellocytes of Cainocreadium labracis were studied by transmission electron microscopy (TEM) and TEM cytochemistry. Four developmental stages were distinguished during vitellogenesis: (I) stem cell of high nucleo-cytoplasmic ratio; (II) early differentiation with chief activity focused on the beginning of protein synthesis and shell globule formation; (III) advanced differentiation with rapid intensification of protein synthesis, progressive fusion of single shell globules into large globule clusters, and formation of unsaturated lipid droplets surrounded by β-glycogen particles; and (IV) mature vitellocyte. Early vitellogenesis with vitellocyte maturation consists of: (1) increase in cell volume; (2) increased development of large, parallel cisternae of GER with production of proteinaceous granules; (3) development of small Golgi complexes that package granules; and (4) within vacuoles, progressive enlargement of proteinaceous granules into shell globule clusters formed during vitellogenesis. Three types of inclusions accumulate in large amounts in mature vitelline cells: (1) shell globule clusters, important component in the formation of egg shell; (2) numerous unsaturated lipid droplets. Though fewer, there are also diphasic droplets consisting of saturated and unsaturated lipids in the same droplet, and (3) a relatively small amount of β-glycogen particles, usually surround a few groups of lipid droplets. The β-glycogen and lipid droplets are nutritive reserves for embryogenesis. General pattern and functional ultrastructure of vitellogenesis greatly resemble those observed in some lower cestodes, such as bothriocephalideans and diphyllobothrideans. Variations and differences in the amount of lipids and of glycogen during vitellogenesis in lower cestodes and other trematodes are compared and discussed.

First finding of Ityogonimus lorum and I. ocreatus co-infection in the Iberian mole, Talpa occidentalis

The Ityogonimus lorum-I. ocreatus co-infection is reported for the first time in the Iberian mole Talpa occidentalis in Asturias (NW Spain). Both Ityogonimus species are stenoxenous helminths of insectivores of the genus Talpa and they have often been found parasitizing the Iberian mole and also the European mole T. europaea, but a mixed infection had not been previously reported. The present study also highlights the main differential morphometric characteristics between I. lorum and I. ocreatus such as the body length, the ventral sucker diameter, the ratio between suckers and the distance between suckers.

Spermatological characteristics of the family Glypthelminthidae (Digenea, Plagiorchioidea) inferred from the ultrastructural study of Glypthelmins staffordi Tubangui, 1928

The present study describes the ultrastructural organization of the mature spermatozoon of the digenean Glypthelmins staffordi (Glypthelminthidae) by means of transmission electron microscopy. Live digeneans were collected from the Chinese edible frog (Hoplobatrachus rugulosus) in Udon Thani Province (Thailand). The ultrastructural study reveals that the mature spermatozoon of G. staffordi is a filiform cell, which is tapered at both extremities. It exhibits the Bakhoum et al.'s type IV of spermatozoon of digeneans characterized by the 9+'1' axonemes of trepaxonematan Platyhelminthes, the presence of the association "external ornamentation-cortical microtubules", the external ornamentation located in the posterior part of the anterior region, the arrangement of parallel cortical microtubules in two bundles and with its maximum number located in the anterior part of the sperm cell, and the presence of two mitochondria. Other characteristics are the presence of spine-like bodies, a posterior extremity containing only the nucleus, and the presence of a large amount of glycogen granules. Results of the present study are particularly compared with the existing data in other families of the Plagiorchioidea, namely the Brachycoeliidae, the Haematoloechidae, the Omphalometridae and the Plagiorchiidae.

Dermatological manifestations in cardiofaciocutaneous syndrome: a prospective multicentric study of 45 mutation-positive patients

BACKGROUND

Data on dermatological manifestations of cardiofaciocutaneous syndrome (CFCS) remain heterogeneous and almost without expert dermatological classification.

OBJECTIVES

To describe the dermatological manifestations of CFCS; to compare them with the literature findings; to assess those discriminating CFCS from other RASopathies, including Noonan syndrome (NS) and Costello syndrome (CS); and to test for dermatological phenotype-genotype correlations.

METHODS

We performed a 4-year, large, prospective, multicentric, collaborative dermatological and genetic study.

RESULTS

Forty-five patients were enrolled. Hair abnormalities were ubiquitous, including scarcity or absence of eyebrows and wavy or curly hair in 73% and 69% of patients, respectively. Keratosis pilaris (KP), ulerythema ophryogenes (UO), palmoplantar hyperkeratosis (PPHK) and multiple melanocytic naevi (MMN; over 50 naevi) were noted in 82%, 44%, 27% and 29% of patients, respectively. Scarcity or absence of eyebrows, association of UO and PPHK, diffuse KP and MMN best differentiated CFCS from NS and CS. Oral acitretin may be highly beneficial for therapeutic management of PPHK, whereas treatment of UO by topical sirolimus 1% failed. No significant dermatological phenotype-genotype correlation was determined.

CONCLUSIONS

A thorough knowledge of CFCS skin manifestations would help in making a positive diagnosis and differentiating CFCS from CS and NS.

Severe parasitism by Versteria mustelae (Gmelin, 1790) in the critically endangered European mink Mustela lutreola (Linnaeus, 1761) in Spain

The riparian European mink (Mustela lutreola), currently surviving in only three unconnected sites in Europe, is now listed as a critically endangered species in the IUCN Red List of Threatened Species. Habitat loss and degradation, anthropogenic mortality, interaction with the feral American mink (Neovison vison), and infectious diseases are among the main causes of its decline. In the Spanish Foral Community of Navarra, where the highest density of M. lutreola in its western population has been detected, different studies and conservation measures are ongoing, including health studies on European mink, and invasive American mink control. We report here a case of severe parasitism with progressive physiological exhaustion in an aged free-ranging European mink female, which was accidentally captured and subsequently died in a live-trap targeting American mink. Checking of the small intestine revealed the presence of 17 entangled Versteria mustelae worms. To our knowledge, this is the first description of hyperinfestation by tapeworms in this species.

Reinvestigation of the sperm ultrastructure of Hypoderaeum conoideum (Digenea: Echinostomatidae)

Spermatological characteristics of the digenean Hypoderaeum conoideum (Echinostomatidae) collected from Anas platyrhynchos in the Lac d'Annecy (France) were reinvestigated using transmission electron microscopy. The previous study on this species only describes the presence of two axonemes of unequal lengths, a mitochondrion, a posterior nucleus, and the disposition of cortical microtubules. The present ultrastructural study reveals that the mature spermatozoon of H. conoideum is a filiform cell tapered at both extremities. The sperm cell exhibits the characteristics of a digenean spermatozoa type V, namely two axonemes of the 9 + '1' pattern of trepaxonematan Platyhelminthes, external ornamentation of the plasma membrane associated with cortical microtubules, and located in the anterior part of the proximal region of the sperm cell, lateral expansions, two bundles of parallel cortical microtubules, maximum number of cortical microtubules in the anterior part of the spermatozoon, and presence of two mitochondria. In addition, the sperm cell of H. conoideum shows spine-like bodies and a posterior extremity with only the nucleus. The ultrastructural characters of the spermatozoon of H. conoideum are compared with those of other digeneans belonging to the superfamily Echinostomatoidea.

Echinococcus multilocularis (Cestoda, Cyclophyllidea, Taeniidae): functional ultrastructure of the penetration glands and nerve cells within the oncosphere

The fine structure of the infective hexacanths of Echinococcus multilocularis was examined with particular emphasis on the functional ultrastructure of penetration glands and nerve cells directly involved in the mechanism of initial host infection. The oncosphere contains two types of penetration glands, PG1 and PG2, that differ slightly in size and form a large U-shaped bi-nucleated syncytial structure. The arms of each gland at each end of the U, directed towards the hook region, exit into the tegument peripheral layer between the median and lateral hook pairs. The lobate nuclei of PG1 and PG2 contain prominent spherical nucleoli surrounded by several large electron-dense islands of heterochromatin. The syncytial cytoplasm of both types of glands is rich in free ribosomes, polysomes, several mitochondria, and heavy accumulations of discoid secretory granules of moderate to high electron density. The secretory granules, sg1 and sg2, differ in their ultrastructure and electron density; the sg2 are much smaller and more flattened in shape. A common characteristic for sg1 and sg2, evident under high magnification, is their high electron density and discoidal shape, with two bi-concave surfaces. Both sg1 and sg2 are frequently grouped in characteristic parallel stacks, the "rouleau"-shaped assemblages with sometimes six to ten granules. Two nerve cells of neurosecretory type are situated in the central part of the hexacanth, each one in a deep U-shaped invagination between the two penetration glands. The nuclei of nerve cells contain several large heterochromatin islands closely adjacent to their nuclear membranes. Their cytoplasm is characterized by having membrane-bound, dense-cored neurosecretory-like granules not only in nerve cell perikarya but also in the elongated nerve processes frequently adjacent to gland arms and to both somatic or body musculature, including the complex system of hook muscles. The results of the present study, when supported with literature data on oncospheres of other cestode species, allow for a better understanding of the important role and coordinated functions of three structural components, i.e., oncospheral hooks, penetration glands, and nerve cells, in the mechanism of intermediate host infection. Presence or absence of nerve cells in oncospheres of various cestodes is reviewed, and perspectives on the value and application of research on functional morphology of oncospheres are discussed.

Ultrastructure of digenean trematode eggs (Platyhelminthes: Neoophora): A review emphasizing new comparative data on four European Microphalloidea

Despite their tremendous diversity and their medical and veterinary importance, details of egg ultrastructure among the digenean trematodes has been studied rather little. The available literature is spread over several decades and several species, but has not been adequately reviewed to reveal patterns of similarity and divergence. We present this review to synthesize and analyse what is known from the available literature reporting studies using both transmission electron microscopy (TEM) and scanning electron microscopy (SEM). To support our general review of existing literature, we also have synthesized our own previously published descriptions, and present herein our new previously unpublished data. From these new electron micrographs, we provide a comparative analysis of the intrauterine eggs of four digenean species, representing four genera and three families of the superfamily Microphalloidea, collected from four different host wildlife species in four European countries: 1) Mediogonimus jourdanei (Prosthogonimidae) from Myodes glareolus (Mammalia: Rodentia), collected in France; 2) Maritrema feliui (Microphallidae) from Crocidura russula (Mammalia: Soricimorpha), collected in Spain; 3) Brandesia turgida (Pleurogenidae) from Pelophylax ridibundus (Amphibia: Anura: Ranidae), collected in Russia; and 4) Prosotocus confusus (Pleurogenidae) from Rana lessonae (Amphibia: Anura: Ranidae), collected in Belarus. All were studied by preparing whole worms by various techniques for TEM, so that eggs could be studied in situ within the uterus of the parent worm. Based on the literature review and the new data presented here, we describe basic similarities in patterns of embryogenesis and egg formation among all trematode species, but substantial variations in timing of larvigenesis, sculpturing of egg shell surfaces, and some other features, especially including accessory cocoon coverings outside the egg shells of B. turgida and P. confusus. In the future, many more studies are needed to explore egg ultrastructure in other digenean taxa, to explore potential phylogenetic patterns in egg development and structure, and to correlate structure with function in the life cycle.

Gastrografin may reduce time to oral diet in prolonged post-operative ileus: a pooled analysis of two randomized trials

BACKGROUND

Gastrografin has been suggested as a rescue therapy for prolonged post-operative ileus (PPOI) but trial data has been inconclusive. This study aimed to determine the benefit of gastrografin use in patients with PPOI by pooling the results of two recent randomized controlled trials assessing the efficacy of gastrografin compared to placebo given at time of PPOI diagnosis.

METHODS

Anonymized, individual patient data from patients undergoing elective bowel resection for any indication were included, stoma closure was excluded. The primary outcome was duration of PPOI. Secondary outcomes were time to tolerate oral diet, passage of flatus/stool, requirement and duration of nasogastric tube, length of post-operative stay and rate of post-operative complications.

RESULTS

Individual patient data were pooled for analysis (53 gastrografin, 55 placebo). Gastrografin trended towards a reduction in PPOI duration compared to placebo, respectively, median 96 h (interquartile range, IQR, 78 h) versus median 120 h (IQR, 84 h), however, this result was non-significant (P = 0.11). In addition, no significant difference was detected between the two groups for time to passage of flatus/stool (P = 0.36) and overall length of stay (P = 0.35). Gastrografin conferred a significantly faster time to tolerate an oral diet compared to placebo (median 84 h versus median 107 h, P = 0.04). There was no difference in post-operative complications between the two interventions (P > 0.05).

CONCLUSION

Gastrografin did not significantly reduce PPOI duration or length of stay after abdominal surgery, but did reduce time to tolerate a solid diet. Further studies are required to clarify the role of gastrografin in PPOI.

Echinococcus multilocularis (Cestoda, Cyclophyllidea, Taeniidae): origin, differentiation and functional ultrastructure of the oncospheral tegument and hook region membrane

Both the oncospheral tegument and the hook region membrane (HRM) of Echinococcus multilocularis hexacanths originate from a syncytial binucleate complex that appears in the early stage of morphogenesis and organogenesis of the hexacanth larva. The primordium of this binucleate complex forms a binucleate syncytial cap or "calotte" situated beneath the inner envelope at one pole of the developing embryo. During oncospheral differentiation, the binucleate perikaryon of the syncytial cap is sunk progressively deeper into the central part of the embryo, but remains always connected with the distal cytoplasm by a tendrillar cytoplasmic connection or bridge. Following migration or sinking of the binucleate perikaryon, numerous cytoplasmic vesicles appear in the distal cytoplasm. These vesicles fuse progressively together and form a single large cavity or lacuna. The walls of this cavity are becoming at this point the walls of two delaminated layers: (1) the distal anucleated cytoplasmic layer is transformed into the oncospheral tegument and (2) the proximal thin cytoplasmic layer is transformed into the "hook region membrane". This delamination of the initially compact layer of distal cytoplasm into two layers seems to be closely associated with differentiation of oncospheral hooks, the elongating blades of which protrude progressively into a newly formed cavity. The pressure of hook blades on the hook region membrane appears to facilitate its further separation from the basal layer of distal cytoplasm which is transformed into the peripheral layer of oncospheral tegument. In the mature oncosphere, the surface of this peripheral layer forms a regular brush border of cytoplasmic processes or microvilli and represents the true body covering of the hexacanth. The very thin cytoplasmic connection between the peripheral layer of tegument and binucleate perikaryon appears only very seldom in the ultrathin sections as a narrow cytoplasmic strand and has a plasma membrane that is reinforced by a single row of cortical microtubules. The HRM covers only one pole of the oncosphere and is attached to the oncosphere surface. The HRM is clearly visible in the mature oncosphere and is draped over the hook blades, the sharp points of which are protected by moderately electron-dense caps. Comparison of the above morphology with that of TEM study of the tegument of adult cestodes shows a great similarity as well as homology in the body covering of both larval and adult cestodes.

Does gastric conditioning decrease the incidence of cervical oesophagogastric anastomotic leakage?

INTRODUCTION

Oesophageal reconstruction by gastroplasty with cervical anastomosis has a higher incidence of dehiscence. The aim of the study is to analyse the incidence of anastomotic leakage in patients undergoing gastroplasty with cervical anastomosis following angiographic ischaemic conditioning of the gastric conduit.

METHODS

Prospective analysis of patients who underwent gastric conditioning two weeks prior to oesophageal reconstruction, from January 2001 to January 2014. The conditioning was performed by angiographic embolization of the left and right gastric artery, and splenic artery. The main variable analysed was the incidence of anastomotic leakage in patients undergoing gastroplasty with cervical anastomosis. Secondary variables analysed were the result of the conditioning, complications arising from that procedure and in the postoperative period, and mean length of postconditioning and postoperative hospital stay.

RESULTS

Gastric conditioning was indicated in 97 patients, with neoplasia being the most frequent aetiology motivating the oesophageal reconstruction (76%). 96 procedures were successfully carried out, arterial embolization was complete in 80 (83%). The morbidity rate was 13%, with no mortality. Postoperative morbidity was 45%; the most frequent complications associated with the surgery were respiratory problems. Six (7%) patients experienced cervical fistula, and all received conservative treatment. The rate of postoperative mortality was 7%.

CONCLUSIONS

In our serie the incidence of anastomotic leakage in patients undergoing gastroplasty with cervical anastomosis following angiographic ischaemic conditioning is 7%. Angiographic ischaemic conditioning is a procedure with acceptable morbidity.

Ultrastructure of the spermatozoon of Macvicaria obovata (Digenea: Opecoelidae), a parasite of Sparus aurata(Pisces: Teleostei) from the Gulf of Gabès, Mediterranean Sea

The ultrastructural organization of the spermatozoon of the digenean Macvicaria obovata (Opecoelidae) is described by transmission electron microscopy. Alive digeneans were collected from the digestive tract of Sparus aurata (Teleostei, Sparidae), caught from the Gulf of Gabès in Chebba, Tunisia (Eastern Mediterranean Sea). The male gamete of M. obovata is a filiform cell, tapered at both extremities and exhibits typical characters such as two axonemes of different lengths showing the 9+'1' trepaxonematan pattern, a nucleus, mitochondria, two bundles of parallel cortical microtubules, external ornamentation of the plasma membrane, spine-like bodies and granules of glycogen. Cortical microtubules are absent in the anterior spermatozoon extremity and appear after the disappearance of the electron-dense material. The first mitochondrion is of moniliform type and it is associated with the external ornamentation of the plasma membrane and spine-like bodies. The second mitochondrion is more posteriorly located, reaching the nuclear region. The present study provides new data on the mature male gamete of M. obovata that may be useful for the understanding of digenean relationships and phylogenetic studies.

Do we publish what we preach? Analysis of the European Society for Surgery of the Shoulder and Elbow Congress publication rates

Background

Scientific congresses have become the most expedient method to communicate novel findings on any research topic. However, an important question is whether this information will be published in peer-reviewed journals. Our aim was to determine the publication rate of the abstracts presented at the European Society for Surgery of the Shoulder and Elbow Congress and analyze factors that may influence this rate.

Methods

A total of 398 abstracts reported in the Abstract Book from the 2008 European Society for Surgery of the Shoulder and Elbow Congress were examined and categorized by oral and poster presentations, topic, and the number of authors listed. A search in PubMed and Google Scholar for subsequent peer-reviewed publications was performed in September 2015. The time to publication after the meeting had been held; the type of journal and its impact factor at the time to publication were recorded for those abstracts that reached peer-reviewed journal publication.

Results

The overall publication rate for the 2008 European Society for Surgery of the Shoulder and Elbow oral and poster presentations was 45.20% after 7 years. The mean time to publication was 18.53 months, and the mean impact factor value was 2.32. Oral presentations were significantly better represented in journals than posters (64.40 vs. 35.40%, p < 0.001). Abstracts with a greater number of authors listed had better publication rates (p < 0.001).

Conclusion

Less than half of the oral presentations and posters at the 21st European Society for Surgery of the Shoulder and Elbow Congress were published in peer-reviewed journals. Oral presentations with a higher number of authors had an increased likelihood of being published.

Origin, differentiation and functional ultrastructure of egg envelopes in the cestode Echinococcus multilocularis Leuckart, 1863 (Cyclophyllidea: Taeniidae)

The origin, differentiation and functional ultrastructure of oncospheral or egg envelopes in Echinococcus multilocularis Leuckart, 1863 were studied by transmission electron microscopy (TEM) and cytochemistry. The purpose of our study is to describe the formation of the four primary embryonic envelopes, namely vitelline capsule, outer envelope, inner envelope and oncospheral membrane, and their transformation into the oncospheral or egg envelopes surrounding the mature hexacanth. This transformation takes place in the preoncospheral phase of embryonic development. The vitelline capsule and oncospheral membrane are thin membranes, while the outer and inner envelopes are thick cytoplasmic layers formed by two specific types of blastomeres: the outer envelope by cytoplasmic fusion of two macromeres and the inner envelope by cytoplasmic fusion of three mesomeres. Both outer and inner envelopes are therefore cellular in origin and syncytial in nature. During the advanced phase of embryonic development, the outer and inner envelopes undergo great modifications. The outer envelope remains as a metabolically active layer involved in the storage of glycogen and lipids for the final stages of egg development and survival. The inner envelope is the most important protective layer because of its thick layer of embryophoric blocks that assures oncospheral protection and survival. This embryophore is the principal layer of mature eggs, affording physical and physiological protection for the differentiated embryo or oncosphere, since the outer envelope is stripped from the egg before it is liberated. The embryophore is very thick and impermeable, consisting of polygonal blocks of an inert keratin-like protein held together by a cementing substance. The embryophore therefore assures extreme resistance of eggs, enabling them to withstand a wide range of environmental temperatures and physicochemical conditions.

Failure of conservative treatment with Gastrografin® for adhesive small bowel obstruction after colorectal surgery

PURPOSE

The aim of this study was to identify risk factors related with failure of conservative management of adhesive small bowel obstruction (ASBO) in patients with previous colorectal surgery.

METHODS

Patients admitted with the diagnosis of ASBO after previous colorectal resection, were included. All patients underwent administration of Gastrografin®. Abdominal radiography was done after 24 h, to confirm the presence of contrast in colon (incomplete obstruction) or not (complete obstruction). Several factors were investigated to study their relationship with the failure of conservative management. Failure of conservative management was considered when emergency operation was needed to solve ASBO.

RESULTS

Incomplete obstruction was observed in 174 episodes (93.0%) while in 13 (7.0%) was complete. One hundred seventy-one ASBO episodes (91.4%) responded successfully to nonoperative treatment and 16 (8.6%) required emergency surgery. Five patients needed bowel resection. Results on the diagnostic test with Gastrografin® showed a sensitivity of 75%, specificity of 99%, positive predictive value 92%, and negative predictive value 98%. Age over 75 years was the only predictive factor for failure of conservative management. The median waiting time from the radiologic confirmation of complete obstruction to surgery was higher in patients requiring bowel resection when compared to those who did not need resection.

CONCLUSIONS

The use of Gastrografin® in ASBO after colorectal resection is a safe and useful tool for the indication of conservative management. Age over 75 years is a predictive factor for need of surgery. Surgery should be performed no later than the following 24 h of confirmed complete obstruction.

Advances in Spermatological Characters in the Digenea: Review and Proposal of Spermatozoa Models and Their Phylogenetic Importance

The wide biodiversity and economic importance of digeneans have motivated a great deal of research in the last decade, focussing on their phylogenetic positions. Molecular research was instrumental for our understanding of phylogeny in the Digenea, but spermatological studies have also provided many results, which are potentially useful for phylogeny; however, the complete spermatological data set has never been reviewed in a whole phylogenetic perspective. Spermatological data are now available for more than 100 species, belonging to 15 superfamilies and 46 families. In this paper, we try to summarize the current knowledge about sperm structure in the digeneans and propose a classification of digenean spermatozoa into five basic models. The main ultrastructural characters used are (1) the type of axoneme, (2) the lateral expansion, (3) the association 'external ornamentation of the plasma membrane + cortical microtubules', (4) the field of cortical microtubules and its number, (5) the location of the external ornamentation, (6) the location of the maximum number of cortical microtubules and (7) the number of mitochondria. We also outline the most interesting features for phylogenetic inference and their possible value in the context of digenean systematics, phylogeny and evolution. Associations between sperm models and superfamilies were found as follows: Type 1 in the Schistosomatoidea; Type 2 in the Hemiuroidea; Type 3 in the Opecoeloidea, Lepocreadioidea, Haploporoidea and Opisthorchioidea; Type 4 in the Gorgoderoidea, Microphalloidea, Plagiorchioidea and Gymnophalloidea; Type 5 in the Echinostomatoidea, Microscaphidioidea, Paramphistomoidea, Pronocephaloidea and Brachylaimoidea.