Unusual Variation Research Articles

Syringocystadenoma Papilliferum-Like Features in Poroma: An Unusual Morphologic Pattern of Poroma or True Synchronous Occurrence of 2 Distinct Neoplasms?

Poromas are benign adnexal neoplasms of eccrine origin, believed to arise from the outer layer of acrosyringia and upper dermal eccrine ducts, with a predilection for glabrous skin. They typically present as a pink or red papule with a surrounding thin moat on the palms and soles. We report a case of poroma with histopathologic features reminiscent of syringocystadenoma papilliferum (SCAP). A 70-year-old woman presented with a 2.0 cm pedunculated nodule on the left suprapubic abdomen. Histopathologically, the lesion predominantly displayed features of a conventional poroma but also included areas with endophytic invaginations lined by large, plump epithelioid cells with abundant eosinophilic cytoplasm and occasional decapitation secretion, alongside a stroma rich in plasma cells-characteristics suggestive of SCAP. However, definitive bilayers with myoepithelial cells were not observed. Immunohistochemical studies revealed that the tumor cells were positive for TRPS1 (particularly around SCAP-like areas) and CEA (indicating ductal differentiation), but negative for BRAF V600E and NUT. The diagnosis of poroma with apocrine differentiation mimicking SCAP was favored. This unusual morphologic variation in poromas is rare, with fewer than 5 cases documented in the literature. These SCAP-like features likely represent a variation within the morphologic spectrum of poromas rather than the presence of 2 synchronous tumors. Our case highlights the importance of recognizing such variations in poroid neoplasms to ensure accurate diagnosis.

Does Proportionality Increase Turnout? A Study of Adaptation to Oscillating Electoral Systems

Does proportionality increase turnout? This article studies a national electoral reform in early twentieth-century Argentina that was implemented asymmetrically across districts, creating a natural laboratory in which some districts oscillated between electoral systems across elections. Leveraging this unusual variation in a difference-in-differences design, this article shows that a shift from multi-member plurality rules towards a slightly more proportional system—which removed one-third of the contested seats from the grasp of the dominant party—led to a four percentage point increase in turnout. An investigation into causal mechanisms indicates that more proportional rules, by increasing the odds that smaller parties obtain seats, promoted strategic party entry and intensified electoral competition, both between and within parties. These findings complement existing quasi-experimental results that focus exclusively on elections in European democracies, confirm that parties are able to adapt immediately to changes in electoral rules, and refute the belief that proportionality does not affect turnout in Latin America.

The Curious Case of Twin Fast Radio Bursts: Evidence for Neutron Star Origin?

Fast radio bursts (FRBs) are brilliant short-duration flashes of radio emission originating at cosmological distances. The vast diversity in the properties of currently known FRBs and the fleeting nature of these events make it difficult to understand their progenitors and emission mechanism(s). Here we report high time resolution polarization properties of FRB 20210912A, a highly energetic event detected by the Australian Square Kilometre Array Pathfinder (ASKAP) in the Commensal Real-time ASKAP Fast Transients survey, which show intraburst position angle (PA) variation similar to Galactic pulsars and unusual variation of Faraday rotation measure (RM) across its two sub-bursts. The observed intraburst PA variation and apparent RM variation pattern in FRB 20210912A may be explained by a rapidly spinning neutron star origin, with rest-frame spin periods of ∼1.1 ms. This rotation timescale is comparable to the shortest known rotation period of a pulsar and close to the shortest possible rotation period of a neutron star. Curiously, FRB 20210912A exhibits a remarkable resemblance to the previously reported FRB 20181112A, including similar rest-frame emission timescales and polarization profiles. These observations suggest that these two FRBs may have similar origins.

Three in one - unusual palmaris longus muscle anatomical variation.

The palmaris longus muscle (PLM) is one of the most variable muscles in human body, pre-senting a wide range of morphological variants such as reversed course, biventer muscle, bi-furcated tendon or total agenesis. Their clinical impact is particularly important in diagnosis and treatment of carpal tunnel syndrome and reconstructive surgery. We present a case of PLM including a previously undescribed combination of variations. A routine dissection of male cadaver aged approximately 60 demonstrated a biventer muscle, with superior and inferior belly being interrupted by a long tendon. The inferior belly passed deep to the flexor retinaculum and its terminal tendon connected to flexor digitorum superfi-cialis tendon for 5th finger. The clinical importance of variations found have been described separately, including unsuita-bility of biventer muscles for tendon reconstruction and increased risk for developing carpal tunnel syndrome in patients with PLM tendon passing deep to the flexor retinaculum. In conclusion, as another variation of PLM is described, it is crucial to bear in mind the poten-tial morphological types of the muscle in diagnosis and treatment of patients, especially in surgery of the hand and forearm.

An unusual variation in the formation and termination of the sciatic nerve - a case report

An unusual variation in the formation and termination of the sciatic nerve - a case report

Subtotal cholecystectomy as an approach to preventing injury in the left-sided gallbladder in the emergency surgery setting: A case study

A left-sided gallbladder is an unusual anatomic variation that makes gallbladder surgery challenging. Two systematic reviews on surgery for left-sided gallbladder highlighted high iatrogenic bile duct injury rates of 4.4% and 7.3%. This paper reports a female in her 40s with symptoms of acute calculous cholecystitis admitted to a secondary health-care center. After inserting four ports through standard sites for conventional gallbladder surgery, laparoscopic inspection revealed a phlegmonous left-sided gallbladder. No discordant situs of abdominal viscera was noted. Laparoscopic surgery was converted to open subtotal closed-tract cholecystectomy. No post-operative complications related to the surgical site were observed. A left-sided gallbladder affected by severe inflammation and infection is an extraordinary condition that should be considered as a risk factor. If an inflamed left-sided gallbladder is encountered, emergency subtotal cholecystectomy is an alternative to total cholecystectomy when the circumstances to adopt the strategies of a culture of safety in cholecystectomy for complete removal of the gallbladder are unfavorable. Relevance for Patients: Subtotal cholecystectomy in patients with left-sided gallbladder reduces the risk for bile duct injuries, outweighing the potential side effects stemming from this surgical approach.

An unusual variation of type IIIC anomalous pancreaticobiliary junction (APBJ)

An unusual variation of type IIIC anomalous pancreaticobiliary junction (APBJ)

An Unusual Anatomical Variation of Accessory Left Gastric Artery Arising from Left Hepatic Artery

An Unusual Anatomical Variation of Accessory Left Gastric Artery Arising from Left Hepatic Artery

An Unusual Variation of the Omohyoid Muscle with Surgical Implications and Review of the Literature

An Unusual Variation of the Omohyoid Muscle with Surgical Implications and Review of the Literature

High bifurcation of the unilateral brachial artery: an unusual variation.

It is common to observe a high bifurcation of the brachial artery, with some variations being quite rare. During routine dissection for medical teaching purposes, a unilateral high bifurcation of the brachial artery was noted on the left side of a female cadaver. On the left arm, two branches of different sizes originate from the axillary artery, one on the radial side and the other on the ulnar side. These branches run down the arm, crossing each other, eventually becoming the forearm's radial and ulnar arteries. We also observed branches such as the posterior circumflex humeral artery, anterior circumflex humeral artery, and deep brachial artery. This case report adds to the existing body of knowledge about the variation of the brachial artery, which is of anatomical and clinical value. We report this case to highlight the unique variation in the arterial anatomy of the upper limb.

Extraction of A Four Rooted Maxillary Third Molars: A Case Series of Rare Occurrence.

It is uncommon to find maxillary molars with four roots, known to have three roots (two buccal and one palatal); it might also havethree, sometimes fused roots. Maxillary third molars have a wide range of morphologies, making it challenging clinically and difficult to distinguishthem radiographically. Given the proximity of the maxillary tuberosity and the floor of the maxillary antrum, the presence of an accessory rootmay complicate a rather straightforward exodontia of the maxillary third molar. We present a case series of three maxillary third molarextractions. The extracted tooth had four roots, an unusual variation in root shape. This case series focuses on morphological changes in theroots of maxillary third molars that are difficult to detect on routine radiographs. Also, this case series highlights the potential for extensivemorphological variation in the maxillary third molar, which could make a simple extraction challenging. To avoid difficulties, cautious extractionmaneuvering is required. Hence it is advisable to prepare for the possibility of an accessory root on a maxillary molar in endodontic and oralsurgical clinical practice to prevent difficulties after surgery. The lesson to be learned from this case series is there can be a possibility for an extraroot in the maxillary third molar, and the dentist must always be alert.Keywords: , , , ,

Unusual Anatomic Variation: Intradural Conjugation of the Hypoplastic Left ICA and the Enlarged Accessory Meningeal Artery

The precise definition of the accessory meningeal artery was not available until 1961. It can originate from the maxillary artery or middle meningeal artery and supplies the meatus and membranous portion of the auditory tube, the lateral pharyngeal muscle, and the medial pterygoid muscle; Laterally, it supplies the lateral pterygoid muscle, the extracranial part of the mandibular nerve, the pterygoid venous plexus, and the sphenoid periosteum. Here, we present a 70-year-old male patient who applied to the neurosurgery clinic with complaints of chronic headaches and dizziness. Magnetic resonance angiography and computed tomography angiography showed hypoplasic appearance of the left internal carotid artery and an enlarged accessory meningeal artery variant merging with its ophthalmic segment.

Detection of preexisting quantum entanglements between dipole–photon discrete observables

We performed measurements of laser beam power polarized in different angles as 0^circ , 45^circ and 90^circ passing close to a symmetric shielded capacitor with parallel plates and through a polaroid filter configured with angles as 0^circ , 45^circ and 90^circ . An unusual light power variation was detected during the charging and discharging of the high voltage capacitor even considering the suppression of known electromagnetic interaction between laser beam and capacitor. The light power variation curves also indicated a typical pattern of charge and discharge of capacitors. The combination of the angles of the laser beam polarization and polaroid filter surprisingly indicated the measurement of correlations between the polarizations of photons and electric dipoles of the capacitor dielectric. These novel results can only be explained supposing the preexisting condition of quantum entanglements between discrete observables of electric dipoles and photons.

Connection between medial dorsal cutaneous nerve and saphenous nerve: case report.

There are no data on the connection of the saphenous nerve (SN), located on the medial side of the foot, with the terminal branches of the superficial fibular nerve. The aim of this study is to reveal the variation that surgeons should pay attention to for anesthesia applied in foot surgeries. In this study, the left foot of a 70-year-old female cadaver fixed with formalin was dissected. The distance to the medial malleolus and the incision line was recorded using digital caliper to determine the reference points in the resulting variation. It was observed that a branch from the SN, which arose from the SN and proceeded anteriorly to the upper part of the medial malleolus and continued towards the dorsum of the foot, hooked with a branch from the medial dorsal cutaneous nerve (MDCN). The branches arising from this hook were distributed on the medial edge of the foot up to the proximal metatarsophalangeal joint I. The distance of this nerve connection to the medial malleolus is 91.14mm, and the distance to the incision line is 15.76mm. It is suggested that the case presented as an unusual SN variation, which may affect the success of local anesthesia in invasive procedures to the medial part of the foot and could be considered in the evaluation of sensory loss after anteromedial surgical approach to the ankle, should be included in the classification of the cutaneous innervation pattern of the foot.

Significant Mid‐ and Low‐Latitude Ionospheric Disturbances Characterized by Dynamic EIA, EPBs, and SED Variations During the 13–14 March 2022 Geomagnetic Storm

AbstractThis work investigates mid‐ and low‐latitude ionospheric disturbances over the American sector during a moderate but geo‐effective geomagnetic storm on 13–14 March 2022 (π‐Day storm), using ground‐based Global Navigation Satellite System total electron content data, ionosonde observations, and space‐borne measurements from the Global‐scale Observations of Limb and Disk (GOLD), Swarm, the Defense Meteorological Satellite Program (DMSP), and the Ionospheric Connection Explorer (ICON) satellites. Our results show that this modest but geo‐effective storm created a number of large ionospheric disturbances, especially the dynamic multi‐scale electron density gradient features in the storm main phase as follows: (a) The low‐latitude equatorial ionization anomaly (EIA) exhibited a dramatic storm‐time deformation and reformation, where the EIA crests evolved into a bright equatorial band for 1–2 hr and then quickly separated back into the typical double‐crest structure with a broad crest width and deep equatorial trough. (b) Strong equatorial plasma bubbles (EPBs) occurred with an abnormally high latitude/altitude extension, reaching the geomagnetic latitude of ∼30°, corresponding to an Apex height of 2,600 km above the dip equator. (c) The midlatitude ionosphere experienced a conspicuous storm‐enhanced density (SED) plume structure associated with the subauroral polarization stream (SAPS). This SED/SAPS feature showed an unusual temporal variation that intensified and diminished twice. These distinct mid‐ and low‐latitude ionospheric disturbances could be attributed to the storm‐time electrodynamic effect of electric field perturbation, along with contributions from neutral dynamics and thermospheric composition change.

Three-rooted Maxillary Premolar: A Case Report of an Unusual Anatomic Variation

Three-rooted Maxillary Premolar: A Case Report of an Unusual Anatomic Variation

Accessory head of the semitendinosus muscle: an unusual variation.

Various studies regarding the morphology of the muscles of the hamstring compartment have exhibited anatomical variations in terms of origin or insertion points. However, variation of the semitendinosus muscle is uncommon. In this case we report an accessory head of the semitendinosus muscle. During routine dissection for medical teaching purposes, a unilateral morphological variant of the semitendinosus muscle was noted on the left side in an 82-year-old female. The accessory head of the semitendinosus muscle originated lateral to the midpoint of the semitendinosus muscle. Fibres of the accessory head originated from the medial border of the long head of biceps femoris as well as the midpoint of the semitendinosus. The accessory head had a common insertion point with the semitendinosus muscle. This case report adds to the existing body of knowledge about the semitendinosus muscle, which is of anatomical and clinical value. Knowledge of the anatomical variants is essential for anatomists and clinicians and may avoid misinterpretation during diagnostic procedures.

Structure and function of the periostracum in the bivalve Perna viridis

The periostracum is an outermost coating of all shelled-molluscs such as bivalves, corresponding to the interfacial layer separating the calcareous shells from the environment. It therefore plays a key role in the growth and survival of bivalves. Nevertheless, the periostracum has attracted little attention. Here, using the optical microscope (OM) and field-emission scanning electron microscope (FE-SEM), we investigate the structure and variation of the periostracum in the green mussel Perna viridis. We find that this periostracum has a novel sandwich structure with an outer (ODL) and inner dense layer (IDL) interleaved with a middle fibrous layer (MFL). The latter consists of locally parallel fibers (57–112 nm wide) and exhibits rich iridescent colors with a reversible hydrochromic behavior. Moreover, we find that this periostracum shows a significant variation in individual shells. Impressively, its thickness varies continuously along the shell edge. In addition, the periostracum at the ventral region is not only the thickest in a shell but also reinforced with the inorganic phosphate. We assume that this unusual variation in a same shell probably originates form defensive adaptations to predation and abrasion. Although many questions remain unanswered, this work reveals a new structure model of the periostracum, which not only advances our understanding of the periostracal formation mechanism, but also provides a natural prototype for design and synthesis of biomimetic coating and photonic materials.

Pulmonary placental transmogrification: a difficult pattern in differential diagnosis of pulmonary hamartomas from a tertiary care hospital in Turkey

ObjectivePulmonary placental transmogrification (PT) is a benign lesion curable by resection, represented by an unusual peculiar morphological variation including placentoid bullous change in the pulmonary hamartoma. In this retrospective study, we aimed to examine the histopathological features of pulmonary hamartomas in lung, to evaluate the different histological components, especially PT, and to investigate importance of PT pattern and its relationship with other clinicopathological features.MethodsThirty-five cases of pulmonary hamartomas were recruited from the records between 2001 and 2021, divided into two groups according to presence of PT, as PT (-) and PT (+) in pathological examination.Results77.1% of all patients were male. There was no significant difference between the two groups in terms of age, sex, comorbidity, presence of symptoms, tumor localization, and radiological findings (P > 0.05). Pulmonary hamartomas were resected totally from 28 patients (80%). Five of these patients (17.9%) had PT components in resection materials with varying degree between 5 and 80%, and all were from male patients. Examination with frozen sections were performed in 15 PT (-) and 5 PT (+) patients but diagnosis with frozen sections was not achieved in any of PT (+) patients. Most of materials included chondroid components (52.22 ± 29.7%) in both groups (P < 0.05).ConclusionThe placental papillary projections are available patterns associated with a pulmonary hamartoma and these projections observed especially in frozen sections are very crucial to recognize PT pattern in hamartomas, as they can result in confusions in differential diagnosis of malignities.

Air quality changes in Taiwan over the past decades and during the COVID-19 crisis

Over the past decades, Taiwan has achieved remarkable goals in air pollution reduction with the concentrations of several common air pollutants such as CO, NOx, PM10, PM2.5, and SO2 going down. In contrast to these achievements, the mitigation of O3 remains extremely tough due to the complexity of its formation process involving synergistic effects of precursor reductions and meteorological influences. During the local COVID-19 crises in Taiwan and the Level 3 alert in 2021, air pollutants directly emitted from the traffic such as CO and NOx present clear relationships with the drop of the recorded freeway traffic volume due to the alert, while PM10 and PM2.5 which are also relevant to the traffic do not show indications of being greatly influenced by the decrease of the traffic flow. Although road traffic is not regarded as a main source of SO2 by current understanding, the unusual SO2 variation patterns found in this study suggest a prolonged impact for months from the changes of travel behavior during the epidemic. In contrast, the epidemic did not exert influences on industrial SO2 concentration which accounts for a large portion of total SO2 in Taiwan, and a similar scenario is also seen in each type of O3 monitoring. Although some results discussed in this study are not in line with current consensuses and understandings in terms of the nation of certain air pollutants, these findings may disclose new perspectives which could be a potential benefit to air quality improvement projects in the future.