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The osseous nasal septum (NS) consists of the perpendicular plate of the ethmoid bone (PPE) and the vomer bone. Few studies evaluated the possibilities of septal pneumatization of the PPE, or adjacent to it. We aimed to observe the anatomical possibilities of NS pneumatizations. A retrospective lot of cone-beam computed tomography (CBCT) files was used. One hundred seventy-one CBCT files from 51 males and 120 females were documented. There were found 46 files that were null for septal pneumatization. The other cases (73.1%) had different septal pneumatizations extended from neighboring air spaces. Pneumatized crista galli (CG) exclusively extended from a frontal sinus was found in 7.01% of cases. The frontal sinuses had minor extensions anterior to the PPE in 7.6% of cases. Unique or double pneumatizations of the sphenoidal rostrum extending within the posterior part of the PPE were detected in 71.34% of cases. In six cases were found ethmoidal pneumatizations of the PPE, either from an anterior ethmoid cell, or from a posterior one, or from a pneumatized CG. In this last case was found a sinus septi nasi of 25.37 mm sagittal size. The supra-septal recesses of the ethmoid air cells were roofing the respective nasal fossa. As all the morphological possibilities of NS pneumatization involve the upper part of the PPE, they should be adequately discriminated anatomically, as well as when the NS and the cribriform plate of the ethmoid bone are approached surgically.

Background and Objectives: Launay’s external carotid vein (ECV) is poorly represented in the anatomical literature, although it is an occasional satellite of the external carotid artery (ECA). We aimed to establish the incidence and morphology of the ECV. Materials and Methods: One hundred computed tomography angiograms were investigated, and ECVs were documented anatomically, when found. Results: Launay’s vein was found in 3/200 sides (1.5%) in a male and two female cases. In two of these cases, the ECV was a replaced variant of the anterior division of the retromandibular vein (RMV), and the facial vein (FV) ended in the external jugular vein. In the third case with the ECV, the RMV was absent and the common FV that resulted from that ECV and the FV drained into the internal jugular vein. The ECV could also appear as an accessory RMV, not just as a replaced one. Additional variants were found, such as fenestration of the external jugular vein (EJV), the extracondylar vein draining the deep temporal veins and an arterial occipitoauricular trunk. Conclusions: Surgical dissections of the ECA in the retromandibular space should carefully observe an ECV to avoid unwanted haemorrhagic events. Approaches of the neck of the mandible should also carefully distinguish the consistent extracondylar veins.

This study aims to assess the frequency of the lingual foramina and canals relative to their location on the mandibular cortical plate and also to closely inspect the course of the lingual canals inside the mandibular body using 3D reconstruction of the evaluated area. A retrospective study was conducted with 55 cone bean computed tomography (CBCT) scans in order to analyze the location, number, course and anastomosing pattern of the lingual canals. A total number of 165 lingual canals (LCs) were recorded from 55 patients, as follows: 94 median (MLC), 16 paramedian (PLC) and 55 lateral lingual canals (LLC). MLCs were a constant finding in all 55 patients (100% of the cases), PLCs were present in 15 patients (27.3% of the cases), and LLCs were identified in 35 patients (63.3% of the cases). The anastomosing pattern of the MLC, in which a supraspinous canal anastomosed with an infraspinous canal, was found in 10.9% of the cases (6 of 55 patients),. The LLCs were anastomosed with the mandibular incisive canal (MIC) in 56.3% of the cases (31 of 55 LLCs) and with the mandibular canal (MC) in 3.6% of the cases (2 of 55 LLCs). CBCT revealed itself to be a reliable tool for evaluating the intramandibular topography of the LCs. The anastomosing pattern of the lingual canals might raise the question whether the LCs could be responsible for incomplete anesthesia after conventional mandibular block by carrying sensory innervation from the mylohyoid nerve to the inferior alveolar nerve.

Telocytes (TCs) are stromal cells defined by peculiar long, thin, moniliform prolongations known as telopodes. When isolated, their morphology often lacks the specificity for the proper definition of a particular cell type. Recent studies have linked TCs with different functions and different cell lineages. Although some authors have studied pulmonary TCs, their research has important limitations that we will attempt to summarize in this article. We will focus our analysis on the following: the culture methods used to study them, the lack of proper discrimination of TCs from lymphatic endothelial cells (LECs), whose ultrastructures are very similar, and the immune phenotype of TCs, which may appear in other cell types such as those related to the endothelial lineage or stem/progenitor cells. In conclusion, the cellular diagnosis of lung TCs should be considered with caution until properly designed studies can positively identify these cells and differentiate them from other cell types such as LECs and stem/progenitor cells. Anat Rec, 303:1280-1292, 2020. © 2019 American Association for Anatomy.

The pneumatisation of the articular tubercle (PAT) of the temporal squama isa rare condition that modifies the barrier between the temporomandibular joint(TMJ) space and the middle cranial fossa. During a routine examination of thecone-beam computed tomography (CBCT) files of patients who were scannedfor dental medical purposes, we identified a case with multiple rare anatomicvariations. First, the petrous apex was bilaterally pneumatised. Moreover, bilateraland multilocular PAT were observed, while on one side it was further found thatthe pneumatic cells were equally dehiscent towards the extradural space and thesuperior joint space. To the best of our knowledge, such dehiscence has not previouslybeen reported. The two temporomastoid pneumatisations were extendedwith occipital pneumatisations of the lateral masses and occipital condyles, thelatter being an extremely rare evidence. The internal dehiscence of the mandibularcanal in the right ramus of the mandible was also noted. Additionally, doublemental foramen and impacted third molars were found on the left side. Suchmultilocular PAT represents a low-resistance pathway for the bidirectional spreadof fluids through the roof of the TMJ. Further, it could add to a morphologicalpicture of hyperpneumatisation of the posterior cranial fossa floor, which couldsignify the involvement of the last four cranial nerves in the clinical picture of TMJpain.

Specific ultrastructural anatomy of masticatory muscles is commonly referred to a general pattern assigned to striated muscles. Junctional feet consisting of calcium channels of the sarcoplasmic reticulum (i.e. the ryanodine receptors, RyRs) physically connected to the calcium channels of the t-tubules build triads within striated muscles. Functional RyRs were demonstrated in the nuclear envelopes of pancreas and of a skeletal muscle derived cell line, but not in muscle in situ. It was hypothesized that ryanodine receptors (RyRs) could also exist in the nuclear envelope in the masseter muscle, thus aiming at studying this by transmission electron microscopy. There were identified paired and consistent subsarcolemmal clusters of mitochondria, appearing as outpockets of the muscle fibers, usually flanking an endomysial microvessel. It was observed on grazing longitudinal cuts that the I-band-limited mitochondria were not strictly located in a single intermyofibrillar space but continued transversally over the I-band to the next intermyofibrillar space. It appeared that the I-band-limited transverse mitochondria participate with the column-forming mitochondria in building a rather incomplete mitochondrial reticulum of the masseter muscle. Subsarcolemmal nuclei presented nuclear envelope-associated RyRs. Moreover, t-tubules were contacting the nuclear envelope and they were seemingly filled from the perinuclear space. This could suggest that nucleoplasmic calcium could contribute to balance the cytosolic concentration via pre-built anatomical routes: (i) indirectly, via the RyRs of the nuclear envelope and (ii) directly via the communication of t-tubules and sarcoplasmic reticulum through the perinuclear space.

Background: The pterygoid fovea on the mandibular neck is superomedial to the mandibular notch and serves to attach the lateral pterygoid muscle.Clinical presentation: During a retrospectiv...

Retrocaval ureter is a congenital abnormality of the right ureter, which has been shown, in rare cases to cause clinical symptoms, mainly due to the development of ureterohydronephrosis. The purpose of this article is to identify the prevalence of the retrocaval ureter, and to emphasize its clinical and surgical importance. A meta-analysis of prevalence, on cases obtained from PubMed, Web of Science, and Scopus databases. A total number of 13 studies contained data that allowed us to estimate the prevalence of the retrocaval ureter, which was identified overall in 9 cases, out of 18,493 subjects. The overall prevalence of retrocaval ureter was 0.13%, with a 95% confidence interval between 0.06 and 0.27%. There was no publication bias, all studies being under the funnel. The overall prevalence of retrocaval ureter is 0.13%. Even if this is obviously a rare condition, its presence must be suspected by practitioners, especially in the presence of urological symptoms without a clear cause.

Multiple mental foramina (MF) are rarely found in the human mandible. We report on the case, as documented using cone beam computed tomography (CBCT), of the triple MF that were identified on the right hemimandible of a 28-year-old female patient. The distal foramen was located on the mandible between the apices of the second premolar root and the first molar mesiovestibular root, being reached by a thin canal that left the mandibular canal. A pair of mesial foramina were identified between the apices of the premolar teeth. Thus, the three foramina corresponded to a surface area of 23.49mm2 of the mandible. On the opposite side, a single mental foramen had a surface area of just 13.25mm2. On each side, retromolar canals that opened into the retromolar fossae were also found. The anatomic possibility of multiple MF increases the surface area at risk during surgical procedures, increases the risk of neurovascular damage and obscures the common tooth-related location of the mental foramen. Practitioners should, therefore, consider a personalised and imaging-documented approach so as to avoid treatment failure.

Organoids are 3D biological structures constructed from stem cells in vitro. They partially mimic the function of real organs. Although the number of articles detailing this technology has increased in recent years, papers debating their ethical issues are few. In addition, many of such articles outline a mere summary of potential ethical concerns associated with organoids, although some have focused on consciousness assessment or organoid use in cystic fibrosis treatment. This article seeks to evaluate the moral status of cerebral organoids and to determine under which conditions their use should be allowed from a bioethical standpoint. We will present an overview of recent steps in developing highly advanced cerebral organoids, followed by an analysis of their ethics based on three factors: human origin, a specific biological threshold (which, once crossed, grants an entity moral status), and the potential to generate human beings. We will also make practical recommendations for researchers working in this biological field. Keywords: Moral status, Cerebral organoids, Moral value

The study of cardiac interstitial Cajal-like cells (ICLCs) began in 2005 and continued until 2010, when these cells were renamed as telocytes (TCs). Since then, numerous papers on cardiac ICLCs and TCs have been published. However, in the initial descriptions upon which further research was based, lymphatic endothelial cells (LECs) and initial lymphatics were not considered. No specific antibodies for LECs (such as podoplanin or LYVE-1) were used in cardiac TC studies, although ultrastructurally, LECs and TCs have similar morphological traits, including the lack of a basal lamina. When tissues are longitudinally cut, migrating LECs involved in adult lymphangiogenesis have an ICLC or TC morphology, both in light and transmission electron microscopy. In this paper, we present evidence that at least some cardiac TCs are actually LECs. Therefore, a clear-cut distinction should be made between TCs and LECs, at both the molecular and the ultrastructural levels, in order to avoid obtaining invalid data.

(1) Background. The vertebral level of origin (VLO) of the celiac trunk (CT) and superior mesenteric artery (SMA) has been scarcely investigated. (2) Method. This study used 107 computed tomography angiograms and an eleven type grading system to classify the VLO of the CT and SMA. Each of the T12–L2 vertebra were divided in three horizontal levels. The intervertebral discs were considered distinct levels. (3) Results. The VLO of the CT ranged from the upper third of the T12 vertebra to the lower third of the L1 vertebra. The VLO of the SMA ranged from the lower third of the T12 vertebra to the upper third of the L2 vertebra. There was a highly significant association between the VLO of the CT and SMA (Chi2 = 201, p &lt, 0.001), usually respecting a “plus two” rule. The mean CT–SMA distance was 1.82 +/− 0.66 cm in males and 1.55 +/− 0.411 cm in females, the difference being statistically significant. The mean CT–SMA distance tended to decrease with increasing CT–SMA types, the differences being statistically significant. (4) Conclusions. These characteristics of CT and SMA origins and their relations should be known by surgeons, as they could impact operative management and should be evaluated on a case-by-case basis.

Hyrtl [Wien Med Wochenschr. 1862;19:291-292] reported firstly the ophtalmopetrosal sinus (OPS) running from the superior orbital fissure and emptying either in the transverse sinus, or in its junction with the superior petrosal sinus. Since then, this anatomic variant was mostly referred and poorly studied. Neither Hyrtl, nor other authors brought any evidence of such OPS. It is hereby reported and proofed such an OPT which was found at dissection. It drained ophthalmic veins and coursed posteriorly, first on the greater wing (alar segment), then on the temporal bone (temporal segment, on the petrosquamous fissure), emptying in the transverse sinus. A lateral type of the superior petrosal sinus connected the OPS and the transverse sinus. The OPS courses on the middle fossa floor, lateral to the Meckel's cavum, foramen ovale, foramen spinosum, and fallopian hiatus. It is a rare thus unexpected finding during specific approaches of the middle fossa floor.

Purpose: To evaluate the actual variability of the mean difference between chronological and dental age using the Cameriere method of open apices and to test its accuracy in variable age groups. Method: We selected studies that contained data about the mean, standard deviation, and number of cases for chronological age, dental age and gender. We used a random-effects model. Statistical significance was estimated, at a p &lt, 0.05, using prediction intervals. For the analysis of publication bias we used the funnel plot and Egger’s regression test for plot asymmetry. I2 was used to test the presence of heterogeneity between studies. The Z test was used to test for statistical differences between subgroups, with p &lt, 0.05 being considered statistically significant. We also used 95% for confidence intervals and prediction intervals. Results: In boys, the average difference between chronological and dental age was 0.44 (0.26–0.63) years, while in girls the average difference between chronological and dental age was 0.34 (0.19–0.49) years. In the 6–7 years age group and in the 14–15 years age group, there was a statistically significant difference between dental and chronological age. Our study shows that the Cameriere method is useful for estimating the chronological age, with errors of less than one year. Conclusions: The Cameriere method of evaluating dental age using open apices is sufficiently accurate for forensic practice, at least in the 7–14 age-interval.

The persisting primitive olfactory artery (PPOA) is a rare anatomic variation of the anterior cerebral artery (ACA), being encountered in less than 1% of cases. Different morphological types were reported previously. In type 3, only once reported previously, the PPOA gives off two branches, a nasal one which courses in the olfactory sulcus to supply the territory of the anterior ethmoidal artery, and the callosomarginal artery. It is reported here a combination of rare anatomic variants found in a 71-year-old male patient investigated by computed tomography angiography. A left PPOA left the A1 segment of the ACA and was classified as subtype 3b, as its branches were the nasal one and a frontal trunk, not the callosomarginal artery. That PPOA had a characteristic hairpin turn applied on the anterior fossa floor. The ACA continued as azygos pericallosal artery, which is also a rare finding. As the nasal branch of the PPOA and its hairpin turn is closely related to the anterior fossa floor, such variant should be carefully documented when combined approaches of the skull base are planned by rhinologists and neurosurgeons.

Background The celiac trunk (CT) commonly trifurcates into the left gastric artery, common hepatic artery (CHA), and splenic artery (SA). The CHA then sends off the proper hepatic artery and gastroduodenal artery (GDA). The arcades of the head of the pancreas are celiacomesenteric anastomoses between branches of the GDA and the superior mesenteric artery. A quadrifurcation of the CT commonly occurs when a different branch is added to the 3 normal ones. An uncommon quadrifurcation of the CT occurs when only one or 2 of the normal branches of the CT participate. Methods The CT quadrifurcations were documented on 112 computed tomography angiograms. Results Five different types of CT quadrifurcation—3 uncommon (types 1–3) and 2 common (types 4–5)—were found in 15/112 cases (13.39%). A marginal significant association was found between the presence of quadrifurcations and male gender (P = 0.05; Fisher's exact test). Type 1 showed a hepatogastric trunk+SA + right hepatic artery+GDA pattern, type 2 had an HGT + right inferior phrenic artery + CHA + SA pattern, type 3 had a gastrophrenic trunk + left inferior phrenic artery+CHA + SA pattern, type 4 showed an left gastric artery + CHA + SA + left inferior phrenic artery combination, and type 5 had an additional common inferior phrenic trunk. One of the type 4 cases showed a buildup of a mesentericomesenteric anastomotic pancreatic arcade between the inferior pancreaticoduodenal arteries, rather than a celiacomesenteric one. Conclusions Anatomic variation of the celiacomesenteric axis is important during hepatobiliary and duodenopancreatic approaches. Therefore, preoperative evaluation is essential because theoretical anatomic possibilities could be real arterial variants.

Only a few studies published until now have described the fascial-tendinous complex between the temporal and the buccinator muscles, which will be reviewed here. In 1957, the "temporo-buccinator band" (TBB) was described by Gaughran, who gave credit to Hovelaque for its first description in 1914. Zenker coined it in 1955 as the "buccotemporal fascia" (BTF). A buccal extension of the temporal muscle tendon extends from the temporal crest of the mandible to insert within the buccinator muscle, anterior to the pterygomandibular raphe, and posterior to the parotid duct that perforates the buccinator. That tendinous expansion is embedded within the buccotemporal fascia, which is oriented antero-infero-medially and joins the buccopharyngeal fascia, forming the TBB/BTF, above which we find the buccal fat pad. The buccal nerve and artery cross this anatomical structure. The TBB/BTF is an additional layer closing the pterygomandibular space anteriorly, and its knowledge is needed for practitioners performing inferior alveolar nerve blocks.

Developmental theories regarding the premaxillary (incisive) suture commonly overlook it separates the premaxillary and maxillary parts of the frontal process of maxilla. Thus, one would expect that neurovascular structures within this transitory mesenchymal zone to appear embedded within the adult frontal process of maxilla. The sutura notha (false suture, Weber's sutura longitudinalis imperfecta) is a poorly described, although constantly present, shallow groove in front of the anterior lacrimal crest, being perforated by a row of holes first described, to our knowledge, by Macalister, in 1884. Macalister's foramina should be discriminated anatomically from the accessory infraorbital foramina. Macalister's foramina lead into canals, usually described as vascular, within the frontal process. We demonstrate in cone-beam computed tomography that these canals, which correspond topographically to Parinaud's vascular canal, are connected, usually through a delicate intraosseous network, with Wood Jones' canalis sinuosus (i.e., the ampullar angle of this canal located above the upper canine tooth). As this later carries the anterior superior alveolar nerve and artery, it is reasonable to consider that the canalar network within the frontal process of maxilla could serve for an accessory distribution of that nerve to the nasolacrimal duct, the atrium of the middle nasal meatus, the agger nasi cell, as well as to the infraorbital (prelacrimal) recess of the maxillary sinus.

Stromal cells/telocytes (SCs/TCs) were recently described in the human adult trigeminal ganglion (TG). As some markers are equally expressed in SCs/TCs and endothelial cells, we hypothesized that a subset of the TG SCs/TCs is in fact represented by endothelial progenitor cells of a myelomonocytic origin. This study aimed to evaluate whether the interstitial cells of the human adult TG correlate with the myelomonocytic lineage. We used primary antibodies for c-erbB2/HER-2, CD31, nestin, CD10, CD117/c-kit, von Willebrand factor (vWF), CD34, Stro-1, CD146, α-smooth muscle actin (α-SMA), CD68, VEGFR-2 and cytokeratin 7 (CK7). The TG pial mesothelium and subpial vascular microstroma expressed c-erbB2/HER-2, CK7 and VEGFR-2. SCs/TCs neighbouring the neuronoglial units (NGUs) also expressed HER-2, which suggests a pial origin. These cells were also positive for CD10, CD31, CD34, CD68 and nestin. Endothelial cells expressed CD10, CD31, CD34, CD146, nestin and vWF. We also found vasculogenic networks with spindle-shaped and stellate endothelial progenitors expressing CD10, CD31, CD34, CD68, CD146 and VEGFR-2. Isolated mesenchymal stromal cells expressed Stro-1, CD146, CK7, c-kit and nestin. Pericytes expressed α-SMA and CD146. Using transmission electron microscopy (TEM), we found endothelial-specific Weibel-Palade bodies in spindle-shaped stromal progenitors. Our study supports the hypothesis that an intrinsic vasculogenic niche potentially involved in microvascular maintenance and repair might be present in the human adult trigeminal ganglion and that it might be supplied by either the pial mesothelium or the bone marrow niche.

The connective stromal and epithelial compartments of the kidney have regenerative potential and phenotypic flexibility. A few studies have shown that cells appertaining to both compartments can exhibit myoid phenotypes. The purpose of our study was to investigate the myoid pattern of kidney and its association with the kidney niches containing stromal cells/telocytes (SC/TCs). We performed an immunohistochemical study using a panel of endothelial, myoid, mesenchymal and stem/progenitor markers, namely CD31, CD34, CD105 (endoglin), CD117/c-kit, nestin, desmin, α-smooth muscle actin (α-SMA) and the heavy chain of smooth muscle myosin (SMM). We used histologically normal kidney samples, obtained after nephrectomy, from nine adult patients. The capsular SC/TCs had a strong CD34 and partial nestin and CD105 immunopositivity. Subcapsular and interstitial SC/TCs expressed c-kit, nestin, CD105, but also α-SMA and SMM, therefore having a myoid phenotype. The endothelial SC/TCs phenotype was CD31+/CD34+/CD105+/nestin±/SMM±/α-SMA±. All three myoid markers were expressed in periendothelial SC/TCs. We also found a scarce expression of nestin in parietal epithelial cells of Bowman's capsule, and in podocytes. In epithelial cells, we found a positive expression for CD31, CD117/c-kit, desmin, CD34, SMM, and CD105. In epithelial tubular cells, we found a predominant basal expression of the myoid markers (SMM and desmin). In conclusion, myoepithelial tubular cells, myoid endothelial cells and myoid SC/TCs are normal constituents of the kidney.

Telocytes (TCs) are stromal cells defined by the presence of long and slender prolongations (telopodes). They are a biologically and functionally heterogeneous population that has not been previously investigated in the sclera. The purpose of this study is to investigate the presence and characteristics of scleral telocytes through a combined immunohistochemical and transmission electron microscopy (TEM) study using samples from ten adult patients. Stromal cells with a TC-like morphology expressed CD34, CD45, CD105, vimentin and occasionally CD68 but were negative for collagen III, CD31, CD133, and CD146. Conjunctival epithelial cells expressed CD45, CD105, CD146, and vimentin. These phenotypes support a scleral niche with immune TCs and haematopoietic stem cells (HSCs). In TEM, we often found spindle-shaped stromal cells projecting telopodes or filopodes, with extremely long nuclei extended even within those prolongations. We separated these cells into a light subtype, which contained a complete set of organelles, and a dark subtype, consisting of undifferentiated stem/progenitor cells. The light cells contained dense vesicles, Weibel–Palade bodies, and rounded α-granule-like structures. These storage areas for the von Willebrand factor (vWF) are known to express selectins that are critically involved in HSC homing and could also indicate endothelial progenitors. The dark cells were scarcely myoid, populated the episcleral perivascular niches and the scleral stroma, and were equipped with lipid storage areas such as lamellar bodies and lipid droplets (LDs). Previously, unreported intranuclear LDs were found in these cells, which is characteristic of an HSC population. It appears that the human scleral stroma is a niche harbouring TC-like cells with immune and HSC phenotypes, and the mere presence or characteristics of telopodes are not enough to differentiate them.

Common anatomic variants of the middle nasal turbinate include its pneumatization (i.e. concha bullosa media) and its paradoxical curvature. We report here two cases of differently combined variations of the middle turbinate which were documented in cone beam computed tomography (CBCT). The first report presents the vertical combination of a double or septated lamellar concha bullosa with the paradoxical curvature of middle turbinate. This combined variant associated (coincidental findings): ipsilateral paradoxical superior turbinate and contralateral paradoxical middle turbinate, concha bullosa superior and concha bullosa suprema. In the second case was found the sagittal combination of successive anterior concha bullosa media and posterior paradoxical curvature of the middle turbinate. An ethmoidal sinolith was found embedded in lamella basalis. The contralateral superior turbinate was pneumatized. These rare findings demonstrate that sound knowledge of possible anatomical variations, supported by a complete use of the tools available for the CBCT documentation of cases, is able to enrich the picture of human anatomic variations, with a direct impact on clinical and surgical practice. The septa-containing lamellar concha bullosa and paradoxical middle concha combination is a variation that affects surgical practice.

We report here anatomic variants which were found during a retrospective study of a male patient, 54 years old, evaluated in computed tomography: heptafurcation of the celiac trunk (CT) and bilateral double renal arteries. The seven branches of the heptafurcated CT were the (1) left and (2) right inferior phrenic arteries, the (3) splenic and (4) left gastric artery, the (5) common hepatic artery, further sending off the (a) proper, continued as left, hepatic artery and (b) the gastroduodenal artery, (6) a replaced right hepatic artery and (7) the dorsal pancreatic artery. To our knowledge, heptafurcation of the CT was not reported previously. The arterial variants have great importance during various surgical and interventional procedures and should be documented prior to respective procedures.

Telocytes (TCs) are a controversial cell type characterized by the presence of a particular kind of prolongations, known as telopodes, which are long, thin, and moniliform. A number of attempts has been made to establish the molecular phenotype of cardiac TCs (i.e., expression of c-kit, CD34, vimentin, PDGRFα, PDGRFβ, etc.). We designed an immunohistochemical study involving cardiac tissue samples obtained from 10 cadavers with the aim of determining whether there are TC-like interstitial cells that populate the interstitial space other than the mural microvascular cells. We applied the markers for CD31, CD34, PDGRFα, CD117/c-kit, and α-smooth muscle actin (α-SMA). We found that, in relation to two-dimensional cuts, the endothelial tubes could be misidentified as TC-like cells, the difference being the positive identification of endothelial lumina. Moreover, we found that cardiac pericytes express PDGRFα, CD117/c-kit, and α-SMA, and that they could also be misidentified as TCs when using light microscopy. We reviewed the respective values of the previously identified markers for achieving a clear-cut identification of cardiac TCs, highlighting the critical lack of specificity.

Background: Telocytes (TCs) are a peculiar morphological type of stromal cells. They project long and moniliform telopodes, visible on various bidimensional sections. Originally regarded as “interstitial Cajal-like cells”, gastrointestinal TCs were CD34+. Further double-labelling studies found that colon TCs are negative for the expressions of the PDGFR-α and α-SMA. However, the TCs in colon were not distinguished specifically from endothelial cells (ECs), vascular or lymphatic. A combinational approach is important for accurate TC identification. Hence, we designed an immunohistochemical study of human colon to check whether ECs and CD34+ TCs express different markers. Methods: Immunohistochemistry was performed on archived paraffin-embedded samples of human colon (nine cases) for the following markers: CD31, CD34, CD117/c-kit and D2-40 (podoplanin). Results: A distinctive population of CD34+ TCs was found coating the myenteric ganglia. However, also perivascular cells and vascular ECs were CD34+. c-kit expression was equally found in interstitial Cajal cells (ICCs) and perivascular cells. The CD34 TCs did not express c-kit. As they were equally CD31- and D2-40- they were assessed as different from ECs. Conclusions: Testing specific markers of ECs, vascular and lymphatic, in the same tissues in which CD34+ TCs are found, is much more relevant than to identify TCs by transmission electron microscopy alone.

The main objective of this article was to analyze prevalence data about myocardial bridging (MB) in published studies. To this purpose, we performed a meta-analysis of studies published in English literature that contained data about the prevalence of MB and its anatomical characteristics. The overall prevalence was 19% (CI: 17-21%); autopsy studies revealed an overall prevalence of 42% (CI: 30-55%), CT studies 22% (CI: 18-25%), and coronary angiography 6% (CI: 5-8%). Most bridges were located on the left anterior descending artery (82% overall, 63% on autopsy studies), had a mean thickness of 2.47 mm and a mean length of 19.3 mm. In conclusion, autopsy studies should be the gold standard in evaluating the actual prevalence of myocardial bridges, while in vivo high-resolution CT scanning should be preferred to coronary angiography studies.

Probably, the most variable anatomic pattern relates to the iliac arteries system. There are reported here multiple rare anatomic variants found in a single case, at CT evaluation: (a) the unilaterally present common trunk of origin of the obturator, inferior epigastric, and medial circumflex femoral arteries and (b) the medial insertion of the deep femoral artery (DFA) onto the femoral artery, which placed the DFA initially on the medial side of the femoral vein. Such rare, but possible, anatomic variations should recommend surgeons to plan the procedures on a case-by-case basis.

Usual descriptions indicate three or maximum four nasal turbinates (conchae) attached to the lateral nasal wall. The middle, superior and, occasionally, supreme ones belong to the ethmoid bone. Few authors include in descriptions the concha that Zuckerkandl described as the fourth or supreme ethmoidal turbinate. Despite some inconsistencies in Zuckerkandl's description, the concha bearing his name lies above Santorini's supreme concha, which, in turn, is above Morgagni's superior concha. Few other authors preferred to name Santorini's concha as the first supreme one and Zuckerkandl's concha as the second supreme one.We retrospectively documented, with various purposes, the archived cone-beam computed tomography files of 350 patients.We found in just one case a unilateral sequence of five nasal turbinates. On the opposite side, only four turbinates were detected. Three-dimensional renderizations confirmed that when two supreme turbinates are found, they are joined in a common posterior tail, which, in turn, joins the tail of the superior turbinate.Co-existence of two supreme conchae could either indicate their origin from different ethmoturbinals, or from the split of a commonly unique supreme one. Zuckerkandl's concha deserves therefore to be considered when anatomical descriptions, or studies, are delivered.

The lacrimal sac (LS) empties in the nasolacrimal duct to drain the tears in the inferior nasal meatus. Different studies indicated the role of the lacrimal pump in the lacrimal drainage. Although controversial, the lacrimal pump mechanism is an extrinsic one, either active, or passive. An intrinsic contractile potential of the LS was not documented previously. We thus aimed a retrospective immunohistochemical study to test the alpha-smooth muscle actin (α-SMA) and h-caldesmon expression in the LS wall. We used archived paraffin-embedded samples of LS from ten adult patients. The α-SMA + phenotype was detected in basal epithelial cells, in subepithelial ribbons of stromal cells, in vascular smooth muscle cells, as well as in pericytes. H-caldesmon was exclusively expressed in pericytes, vascular smooth muscle cells and myoepithelial cells of the subepithelial glands. The most striking feature we found in all samples was a consistent stromal network of α-SMA+/h-caldesmon- myofibroblasts. This finding supports an intrinsic scaffold useful for the lacrimal pump.

The lateral (temporal) wall of the orbit separates it from the temporal fossa and the anterior part of the temporal muscle. Within this wall, the sphenozygomatic suture joins the greater wing of the sphenoid bone and the zygomatic bone. We retrospectively documented in cone-beam computed tomography the anatomy of the orbit in a 56-year-old female and we found a previously unreported anatomic variant. The greater wing of the sphenoid bone and the zygomatic bone were separated, bilaterally, by a large unossified space which we termed the sphenozygomatic fissure. This was merged inferiorly with the inferior orbital fissure. A possible imbalanced mechanism of membranous ossification of both the zygomatic bone and the orbital surface of the greater wing could be speculated as a possible cause for such sphenozygomatic fissure. This previously undocumented anatomic variant is of high clinical relevance, since it may allow orbital fat to herniate (or bulge) toward the temporal fossa, it may be easily damaged during minor trauma and it should be carefully approached during the surgery of the orbit through the lateral wall.

The infraorbital nerve (ION) and artery (IOA) course in the infraorbital canal (IOC) to exit through the infraorbital foramen (IOF). Few previous studies brought evidence of accessory IOF. Evaluation of the IOF in Cone Beam Computed Tomography (CBCT) is more accurate to determine whether or not foramina of maxilla are supplied by canaliculi deriving from the IOC. We performed a retrospective anatomical study of the CBCT files of 200 patients. An accessory infraorbital foramen located inferior to the infraorbital margin (AIOF) was found in 18/200 right maxillae and in 13/200 left ones. Canaliculi deriving from the IOC supplied accessory foramina in the sutura notha- AIOF(SN) - in 15 maxillae. Noteworthy, the AIOF(SN)-negative maxillae displayed the SN and the vascular foramina of Macalister. In 94% of cases the AIOF were unique. A single maxilla (3%) had a double AIOF. In a different case (3%) were found three accessory infraorbital foraminules transforming the anterior wall of the antrum into a veritable lamina cribriformis infraorbitalis. A single prior study distinguished AIOF from AIOF(SN), while most of different other ones were performed on dry bones. Therefore, the reports of prevalence for the number and location of AIOF should be regarded with caution. Foramina of the SN could equally get intraosseous and extraosseous supply, this distinction being accurately made in CBCT.

Summary Objective The infraorbital canal (IOC) courses through the roof of the maxillary sinus (MS). Different grading systems concerning the topography of the IOC have been proposed. Further, it has been suggested that a transantral IOC would be morphologically related to Haller's cells (HCs). However, we hypothesized that this is not necessarily the case. Hence, we aimed to study the anatomical possibilities of the air spaces located medially to the IOC. Materials and methods The cone-beam computed tomography (CBCT) files of 40 adult patients were retrospectively evaluated. Results The transantral type of IOC was found in 32.5% of patients. The infraorbital recesses of the MS were found medial to the IOC in 20% of patients. As referred to the nasolacrimal canal, these recesses were either prelacrimal (appearing as false isolated air cells) or retrolacrimal (appearing as false HCs). True HCs were found in 10% of patients. They were located medial to the IOC and they drained into the ethmoidal infundibulum (EI), which was distinct from the MS drainage. In 15% of patients, aerated nasolacrimal ducts (NLDs) were found anterior to the EI and medial to the antral angle. They were capable of masquerading either a HC or an infraorbital recess of the MS. Conclusion Previous classifications of the IOC, which related it to HCs, were reviewed and the evidence was found to be insufficient to assess the HC-related topography of the IOC. Therefore, to achieve the accurate anatomical identification of the air spaces neighbouring the IOC, the infraorbital recesses of the MS, the HCs, and the aerated NLDs should be carefully discriminated within the antero-supero-medial antral angle.

Background The oral mucosa protects the underlying tissue from mechanical damage as well as from the entry of exogenous particles and microorganisms. Telocytes (TCs) are disputed stromal cells featuring peculiarly long and thin processes with uneven calibre known as telopodes, which play a number of roles within the interstitia. The present study aimed to test the key markers recommended for discriminating between TCs and false TCs in samples of normal oral mucosa. Methods Archived paraffin-embedded oral mucosa samples were tested by means of immunohistochemistry with the following markers: CD34, D2-40, CD31 and CD68. Results The epithelial expression of CD68, D2-40 and CD34 was detected. Two subsets of CD34-expressing stromal cells were identified, large cells with telopodial processes, presumably of the hematopoietic lineage, and spindle-shaped TC-like cells. Macrophages and TC-like cells within the lamina propria expressed CD68. The lymphatic endothelia were found to express CD31 and D2-40, but not CD34. Sprouting lymphangiogenesis was demonstrated by the lymphatic endothelial tip cells, which were projecting thin processes within the connective stroma. Conclusions The epithelial expression of CD68 suggests the professional phagocytic potential of the oral epithelium. Regarding the TCs and TC-like cells in the oral mucosa they could not be accurately distinguished from other possible cell types, neither on morphological basis (evidence of telopodes) nor by use of panels of markers which include CD34.

This study aimed to investigate the prevalence of tympanic plate (TP) pneumatisation as well as the various potential patterns. A retrospective study involving the archived Cone-Beam Computed Tomography (CBCT) files of 70 patients was performed to investigate anatomical variations of TP pneumatisation. Forty-eight TPs were found to be non-pneumatised, while 92 were found to contain at least peritubal air cells. Twenty patients (28.5%) did not present any variety of TP pneumatisation, while 36 patients (51.4%) exhibited a symmetrical pattern of pneumatisation. Aside from those patients who lacked TP pneumatisation, the peritubal pneumatisation pattern was found to be the most common. Further, bilateral symmetry was found to occur in more than half of all cases. CBCT is a powerful diagnostic tool, although appropriate knowledge of the anatomical possibilities remains mandatory for adequate surgical planning.

The main aim of this article is to establish the actual prevalence of renal vein variations (circumaortic renal vein, retroaortic renal vein, double renal vein), and to increase awareness about them. To this purpose, we have performed a meta-analysis of prevalence, using the MetaXL package, We included 105 articles in the final analysis of prevalence, of which 88 contained data about retroaortic renal vein, 84 – about circumaortic renal vein, and 51 - about multiple renal veins. The overall prevalence for retroaortic renal vein was 3% (CI:2.4–3.6%), for circumaortic renal vein − 3.5% (CI:2.8–4.4%), and for multiple renal veins - 16.7% (14.3–19.2%), much higher on the right 16.6 (14.2–19.1%) than on the left side 2.1 (1.3–3.2%). The results were relatively homogenous between studies, with only a minor publication bias overall.

There are only a few studies regarding gut subepithelial telocytes (TCs). The telopodes, namely peculiar TCs&rsquo, prolongations described on two-dimensional cuts, are not enough to differentiate this specific cell type. Subepithelial TCs were associated with the intestinal stem niche but a proper differential diagnosis with lymphatic endothelial cells (LECs) was not performed. In this study, we will critically review studies suggesting that distinctive TCs could be positioned within the lamina propria. Additionally, we performed an immunohistochemical study of human gastric mucosa to test the expression of D2-40, the lymphatic marker, as well as that of CD31, CD34, CD44, CD117/c-kit, &alpha, smooth muscle actin (&alpha, SMA) and vimentin in the gastric subepithelial niche. The results support the poorly investigated anatomy of intramural gastric lymphatics, with circumferential collectors located on both sides of the muscularis mucosae (mucosal and then submucosal) and myenteric collectors in the muscularis propria. We also found superficial epithelial prelymphatic channels bordered by D2-40+ but CD31&ndash, TC-like cells. Deep epithelial lymphatic collectors drain in collectors within the lamina propria. Blood endothelial cells expressed CD31, CD34, CD44, and vimentin. Therefore, the positive diagnosis of TC for subepithelial CD34+ cells should be regarded with caution, as they could also be artefacts, resulting from the two-dimensional examination of three dimensional structures, or as LECs. Lymphatic markers should be routinely used to discriminate TCs from LECs.

(1) Background: The optic strut (OS) is a critical landmark for clinoid and paraclinoid surgical interventions. To our knowledge, the current literature only mentioned the OS as a possibility for a lesser sphenoidal wing (LSW) pneumatization path, without a proper study of the pneumatization patterns and prevalence within this structure. Thus, our aim was to fill in the missing information. (2) Methods: A retrospective study on 80 cone beam computed tomography (CBCT) files was conducted to assess the prevalence and the origins of pneumatization within the OS. (3) Results: The pneumatization patterns of the OS were: 56.25% from the sphenoid sinus, 1.25% from the posterior ethmoid air cells (PEAC), and 10% from Onodi cells (ONC). Simultaneous pneumatization of unique origin within the lesser sphenoidal wing (LSW) was found in 26.25% from the sphenoid sinus, 1.25% from PEAC, and 5% from ONC. Communication between both LSW roots through pneumatization was found in 6.25% of the files. (4) Conclusions: A careful radiological examination should precede clinical diagnosis and surgical interventions in the paraclinoid area to evaluate postoperative surgical risks and possible diffusion patterns for infection. Additionally, pneumatization within the OS alters its morphological features and thus, its utility as a landmark.

The rare anatomic variants of the celiac trunk and superior mesenteric artery include the hepatosplenic, hepatosplenomesenteric (HSMT), celiacomesenteric, hepatomesenteric and gastrosplenic trunks. We report a 72-year-old female patient whose computed tomography angiograms indicated a rare anatomic feature whereby the right inferior phrenic artery was inserted in the origin of an HSMT, thus modifying it into a hepatosplenomesentericophrenic trunk (HSMPT). Above the HSMPT, the insertion of the left inferior phrenic artery in the origin of the left gastric artery determined a left gastrophrenic trunk (GPT). Proper identification of this type of rare anatomic variant is of utmost importance prior to different surgical procedures. For example, an HSMT origin of the right inferior phrenic artery is surgically relevant if this artery is an extrinsic pedicle of a hepatocellular carcinoma and is used for embolization of the tumor.

Telocytes (TCs) are morphologically defined as small-sized cells with long, thin, moniliform processes called telopodes (Tps). Numerous papers imply that TCs are a distinctive cell type, and that transmission electron microscopy (TEM) is the gold standard tool for their identification. We aimed to reproduce previous studies on myocardial TCs to check their validity. For this purpose we performed an immunohistochemical study on human cardiac samples from six autopsied donor cadavers, using antibodies against CD10, CD31, CD34, CD146, Ki67, alpha-smooth muscle actin (α-SMA), Platelet-Derived Growth Factor Receptor-alpha (PDGFRα) and laminin. Additionally we performed a TEM study on cardiac samples from three human autopsied donor cadavers and five adult Sprague-Dawley rats. We found endothelial cells (ECs), cords, and filopodia-projecting endothelial tip cells (ETCs) that expressed CD10, CD31, CD34, CD146, and PDGFR-α. Often, endothelial cells closely neighbored the sarcolemmal basal laminae. Endothelial progenitor cells, as well as nascent capillaries, were CD31+/CD34+. Proliferative endothelial cells expressed Ki67. In larger vessels we found pericytes that expressed CD146 and α-SMA; scarce α-SMA-expressing spindle-shaped cells lining cardiomyocytes were suggestive of a pericytic role in angiogenic sprout guidance. The TEM study showed that endothelial tubes are almost exclusively found in the narrow myocardial interstitia. ECs that built them up appeared identical to the cells that previous TEM studies have suggested to be myocardial telocytes. A subset of stromal cells with TC-like phenotype and telopodes-like processes actually seem to configure blood vessels, and therefore belong to the endothelial lineage. This study shows that data presented in previous studies on myocardial telocytes is not enough to allow the reproducibility of the results. At least a subset of cells considered to be TCs might belong to the endothelial lineage.

Neurons from sensory ganglia are exposed to oxidative attack in diabetes. Altered mitochondrial morphologies are due to impaired dynamics (fusion, fission) and to cristae remodeling. This study aimed to evaluate using transmission electron microscopy mitochondrial changes in diabetic trigeminal ganglia suggestive for ignition of apoptosis, in absence of "classical" morphological signs of apoptosis. We used samples of trigeminal ganglia (from six type 2 diabetes human donors and five streptozotocin (STZ)-induced diabetic rats). In human diabetic samples we found three main distributions of mitochondria: (a) small "dark" normal mitochondria, seemingly resulted from fission processes; (b) small "dark" damaged mitochondria, with side-vesiculations (single- and double-coated), large matrix vesicles and cytosolic leakage of reactive species, mixed with larger "light" mitochondria, swollen, and with crystolysis; (c) prevailing "light" mitochondria. In STZ-treated rats a type (c) distribution prevailed, except for nociceptive neurons where we found a different distribution: large and giant mitochondria, suggestive for impaired mitochondrial fission, mitochondrial fenestrations, matrix vesicles interconnected by lamellar cristae, and mitochondrial leakage into the cytosol. Thus, the ultrastructural pattern of mitochondria damage in diabetic samples of sensory neurons may provide clues on the initiation of intrinsic apoptosis, even if the classical morphological signs of apoptosis are not present. Further studies, combining use of biochemical and ultrastructural techniques, may allow a better quantification of the degree in which mitochondrial damage, with membrane alterations and cytosolic leaks, may be used as morphological signs suggesting the point-of-no return for apoptosis. Anat Rec, 299:1561-1570, 2016. © 2016 Wiley Periodicals, Inc.

Although confusions persist in what concerns the terminologies used for describing the fibroblastoid cells of the stromal compartments, the expression of antigens in such cells gradually directs their diagnosis towards a stem/progenitor phenotype. The stromal cells with long, slender and moniliform prolongations were named "telocytes" (TCs), their cell processes being termed "telopodes". However, the mammary gland TCs were not evaluated for the CD34 expression. Thus an in vivo immunohistochemical study was designed; antibodies against CD10, CD34, CD117/c-kit and vimentin were applied on human mammary gland samples of 8 donor patients. Resident CD34-positive stromal cells positive for the TCs morphology were found building consistent stromal networks and ensheathing microvessels and excretory units. Such cells were CD10±/c-kit-/vimentin+. According to the current concepts regarding the in vivo stem/progenitor cells the CD34+ TCs of the mammary stroma could be actors in the mammary stem niche and their antigens expression could relate to different stages of differentiation.

BACKGROUND. The infraorbital recess of the maxillary sinus can reach in front of the nasolacrimal duct to become prelacrimal recess. During a routine Cone Beam CT (CBCT) study of a male patient of 72 years old, there were bilaterally found infraorbital maxillary air cells (IMACs) resulted after the almost complete closure of infraorbital recesses of the maxillary sinuses. Only that on the left side was reaching in front of the nasolacrimal canal. The closure of each infraorbital recess leaded to a narrow draining passage opened in the terminal end of the maxillary infundibulum, thus proximal to the maxillary sinus ostium. On the left side, a small cell of the lacrimal bone was interposed between the IMAC drainage pathway and the nasolacrimal canal. On the right side, the nasolacrimal canal was communicating with the ethmoidal infundibulum. Such an anatomic variation in the infraorbital angle of the maxillary sinus can impede the endoscopic procedures which use the anterior lacrimal pathway.

Telocytes (TCs) are typically defined as cells with telopodes by their ultrastructural features. Their presence was reported in various organs, however little is known about their presence in human trigeminal ganglion. To address this issue, samples of trigeminal ganglia were tested by immunocytochemistry for CD34 and examined by transmission electron microscopy (TEM). We found that TCs are CD34 positive and form networks within the ganglion in close vicinity to microvessels and nerve fibers around the neuronal-glial units (NGUs). TEM examination confirmed the existence of spindle-shaped and bipolar TCs with one or two telopodes measuring between 15 to 53 μm. We propose that TCs are cells with stemness capacity which might contribute in regeneration and repair processes by: modulation of the stem cell activity or by acting as progenitors of other cells present in the normal tissue. In addition, further studies are needed to establish if they might influence the neuronal circuits.

Background Commonly, but not exclusively, the celiac trunk (CT) trifurcates into the left gastric (LGA), common hepatic (CHA) and splenic (SA) arteries. Additional branches of the CT are scarcely reported in the literature. Less than ten reports were found presenting patterns of pentafurcation of the CT (pCT), all being resulted after anatomic dissections. Method We hereby report such a rare pCT, which was found on the computed tomography angiograms of a 71 years old female patient. Results From that CT were leaving three collateral branches, two ascending and one descending, and two terminal branches. The ascending ones were the left inferior phrenic artery and a secondary hepatogastric trunk, further divided into a replaced left hepatic artery and the left gastric artery. The dorsal pancreatic artery was the descending collateral branch of the pCT. The pCT ended by dividing into the CHA and SA. The CHA reached the anterior side of the portal vein to divide into the gastroduodenal and right hepatic arteries. An accessory right hepatic artery left the superior mesenteric artery (SMA) and ascended posterior to the portal vein. Conclusions To the authors’ knowledge, the combination of a pCT and a hepatic branch from the SMA, which raises to three the main arteries of the liver, was not reported previously. Additional branches of the CT should be carefully documented by computed tomography prior to surgical or interventional approaches of the aorta in the celiac region.

Sinoliths are calculi found particularly in paranasal sinuses, the rarest location being the ethmoid air cells. There were previously reported only 4 cases of unilateral large ethmoidal sinoliths (ES), this one being the fifth report. We report here the incidental bilateral evidence in a 34-year-old female patient evaluated in Cone Beam Computed Tomography (CBCT) of minor ES. The left ES, of 1.6 mm2 sagittal size, occupied the suprabullar cell, in front of the ground lamella and behind the anterior ethmoidal canal. The right ES, of 7.6 mm2, was located behind the ground lamella. The radiodensity of each ES was about 1000 HU, their bone quality being thus assessed. This is the first evidence of bilateral and clinically silent ethmoidal sinoliths. Being small-sized and incidentally found, it seems reasonable to consider that ethmoidal sinoliths could have a higher incidence but they are overlooked due to the lack of clinical manifestations.

Uterine leiomyomas, also known as uterine fibroids (UFs), are benign smooth muscle cells tumors, the most frequent tumors in women. Even though UFs are monoclonal tumors, they contain a heterogeneous and versatile cells population. There are scarce proofs about the processes of transdifferentiation that might occur in UFs, modify the tumor microenvironment and support blood and lymph vessels formation. The stromal niches of the UFs harbor cells with angiogenic∕lymphangiogenic, as well as with vasculogenic∕lymphvasculogenic potential, which belong to a phenotypic continuum between the endothelial and mesenchymal lineages. Within these niches, the expressions of CD44 and podoplanin were less investigated and regarded as markers of such processes of transdifferentiation.

Summary The lateral nasal wall attaches the nasal turbinates, which could be, either pneumatized, or paradoxically curved. The turbinate pneumatization–concha bullosausually indicates the pneumatization of the middle turbinate. However, concha bullosasuperior (CBS) is also, although rare, anatomic possibility of variation. We report here a case of unilateral giant septated CBS, which was not, to our knowledge, previously reported. The case was documented in Cone Beam Computed Tomography (CBCT). Subtle pneumatizations of inferior turbinates were found bilateral, as also were the middle conchae bullosae. The left concha bullosasuperior was very large (17.43/5.34 mm), dropping down between the left middle turbinate and the contralaterally deviated nasal septum, and contacting the paradoxical curvature of the middle turbinate on that side. An incomplete oblique septum divided it incompletely into anterior and posterior chambers, it was communicating with a posterior ethmoid air cell, and was draining in the superior meatus. Care should be taken not to misdiagnose a giant CBS as a middle turbinate pneumatization, in order not to misjudge surgical corridors. Therefore, a careful anatomic CT or CBCT diagnosis would be of use for the plan of treatment.

All tissues are known to contain stem cells niches. The dental pulp stem cells (DPSCs) are highly proliferative and can differentiate to various cell types, including endothelial cells. We aimed to evaluate the ultrastructural characteristics of the human dental pulp niche corresponding to the frontal teeth. We found bona fide quiescent DPSCs with high nucleoplasmic ratios, as well as poorly differentiated cells with increased amount of cytoplasm, these later being indicated as dental pulp progenitor cells (DPPCs). Vasculogenic cords were built up by mitotic endothelial progenitor cells with a peculiar trait: giant nucleoli extruded within the cytoplasm. They were either partly embedded within the nuclei, case in which their adnuclear side was coated by marginal heterochromatin and the abnuclear side was coated by a thin rim of ribosomes, or were completely isolated from the nuclei, being covered by ribosomes and surrounded by cytoplasmic fragments of chromatin. To our knowledge such giant extruded nucleoli were not previously reported in any human stem niche or cell type, although similar evidence was gathered in other species as well as in plants. They relate perhaps to intermediate stages of differentiation within the dental niche, thus appearing as transient structures. Their role needs further investigations as it looks that not only nucleolar proteins are exported into the cytoplasm, but the entire nucleolus could be extruded.

Objective The primary aim of this article was to establish the actual prevalence of transposition and duplication of the inferior vena cava and to increase awareness about them. Methods A meta-analysis of prevalence was conducted of cases obtained from PubMed, Web of Science, and Scopus databases. Results A total of 48 studies contained data that allowed us to estimate the prevalence of these variants (39 for duplication and 32 for transposition). The overall prevalence of duplication was 0.7%, with a 95% confidence interval between 0.5% and 0.9%; for transposition, the prevalence was 0.3%, with a 95% confidence interval between 0.2% and 0.5%. The publication bias was minimal. Duplication prevalence was significantly higher in anatomy studies compared with imaging and surgery studies; for transposition, there were no statistically significant differences by detection technique. Conclusions The overall prevalence of duplication of the inferior vena cava is 0.7%; for transposition, it is 0.3%. Even if they are obviously rare conditions, their presence must be suspected by practitioners as they can have important clinical consequences, may require changes in the surgery protocol, or can be associated with other congenital abnormalities.