Principales tipos de quistes en dermatopatología: Parte 2 / Main Types of Cysts in Dermatopathology: Part 2

Este es el segundo artículo de una serie de dos publicados en esta revista, en los que examinamos las características histopatológicas, así como el diagnóstico diferencial, de las principales entidades que se presentan en forma de estructuras quísticas y pseudoquísticas en la biopsia cutánea. En este segundo artículo, abordamos los quistes cutáneo ciliado, branquial, de Bartholino, onfalomesentérico, tímico, del conducto tirogloso, sinovial, y del rafe medio, así como el mucocele, el ganglión y los pseudoquistes auricular y mixoide digital. (AU)

This is the second article in a two-part series published in this journal, in which we examine the histopathological characteristics, as well as the differential diagnosis, of the main entities that present as cystic and pseudocystic structures in cutaneous biopsy. In this second article, we address ciliated cutaneous cysts, branchial cysts, Bartholin's cysts, omphalomesenteric cysts, thymic cysts, thyroglossal duct cysts, synovial cysts, and median raphe cysts, as well as mucocele, ganglion, and auricular and digital myxoid pseudocysts. (AU)

Photoperiodism of Diapause Induction in the Silkworm, Bombyx mori.

The silkworm Bombyx mori exhibits a photoperiodic response (PR) for embryonic diapause induction. This article provides a comprehensive review of literature on the silkworm PR, starting from early works on population to recent studies uncovering the molecular mechanism. Makita Kogure (1933) conducted extensive research on the PR, presenting a pioneering paper on insect photoperiodism. In the 1970s and 80s, artificial diets were developed, and the influence of nutrition on PR was well documented. The photoperiodic photoreceptor has been investigated from organ to molecular level in the silkworm. Culture experiments demonstrated that the photoperiodic induction can be programmed in an isolated brain (Br)-subesophageal ganglion (SG) complex with corpora cardiaca (CC)-corpora allata (CA). The requirement of dietary vitamin A for PR suggests the involvement of opsin pigment in the photoperiodic reception, and a cDNA encoding an opsin (Boceropsin) was cloned from the brain. The effector system concerning the production and secretion of diapause hormone (DH) has also been extensively investigated in the silkworm. DH is produced in a pair of posterior cells of SG, transported to CC by nervi corporis cardiaci, and ultimately released into the hemolymph. Possible involvement of GABAergic and corazonin (Crz) signal pathways was suggested in the control of DH secretion. Knockout (KO) experiments of GABA transporter (GAT) and circadian clock genes demonstrated that GAT plays a crucial role in PR through circadian control. A model outlining the PR mechanism, from maternal photoperiodic light reception to DH secretion, has been proposed.

An Updated Guide to the Identification, Quantitation, and Imaging of the Crustacean Neuropeptidome.

Crustaceans serve as a useful, simplified model for studying peptides and neuromodulation, as they contain numerous neuropeptide homologs to mammals and enable electrophysiological studies at the single-cell and neural circuit levels. Crustaceans contain well-defined neural networks, including the stomatogastric ganglion, oesophageal ganglion, commissural ganglia, and several neuropeptide-rich organs such as the brain, pericardial organs, and sinus glands. As existing mass spectrometry (MS) methods are not readily amenable to neuropeptide studies, there is a great need for optimized sample preparation, data acquisition, and data analysis methods. Herein, we present a general workflow and detailed methods for MS-based neuropeptidomic analysis of crustacean tissue samples and circulating fluids. In conjunction with profiling, quantitation can also be performed with isotopic or isobaric labeling. Information regarding the localization patterns and changes of peptides can be studied via mass spectrometry imaging. Combining these sample preparation strategies and MS analytical techniques allows for a multi-faceted approach to obtaining deep knowledge of crustacean peptidergic signaling pathways.

The sternoclavicular ganglion cyst, a rare pediatric diagnosis.

We briefly describe the case of a 4-year-old girl, referred for imaging of a small, firm, round, skin-colored, subcutaneous nodule that suddenly appeared at her right sternoclavicular junction. A plain radiograph was non-contributory, but ultrasonography revealed a small cystic structure, leading to the diagnosis of a sternoclavicular ganglion cyst. Sternoclavicular ganglion cysts are a rare diagnosis, with only seven reported pediatric cases. A watchful waiting approach can be adopted so long as they remain asymptomatic.

ISL1 and POU4F1 Directly Interact to Regulate the Differentiation and Survival of Inner Ear Sensory Neurons.

The inner ear sensory neurons play a pivotal role in auditory processing and balance control. Though significant progresses have been made, the underlying mechanisms controlling the differentiation and survival of the inner ear sensory neurons remain largely unknown. During development, ISL1 and POU4F transcription factors are co-expressed and are required for terminal differentiation, pathfinding, axon outgrowth and the survival of neurons in the central and peripheral nervous systems. However, little is understood about their functional relationship and regulatory mechanism in neural development. Here, we have knocked out Isl1 or Pou4f1 or both in mice of both sexes. In the absence of Isl1, the differentiation of cochleovestibular ganglion (CVG) neurons is disturbed and with that Isl1-deficient CVG neurons display defects in migration and axon pathfinding. Compound deletion of Isl1 and Pou4f1 causes a delay in CVG differentiation and results in a more severe CVG defect with a loss of nearly all of spiral ganglion neurons (SGNs). Moreover, ISL1 and POU4F1 interact directly in developing CVG neurons and act cooperatively as well as independently in regulating the expression of unique sets of CVG-specific genes crucial for CVG development and survival by binding to the cis-regulatory elements including the promoters of Fgf10, Pou4f2, and Epha5 and enhancers of Eya1 and Ntng2 These findings demonstrate that Isl1 and Pou4f1 are indispensable for CVG development and maintenance by acting epistatically to regulate genes essential for CVG development.

A Modified Approach for Arthroscopic Excision of Dorsal Midcarpal Ganglion Cysts Using Radiocarpal Portals.

Wrist arthroscopy could be a treatment option for dorsal ganglion cysts. To achieve a thorough dorsal capsulectomy for the removal of midcarpal ganglion cysts, it is commonly necessary to combine both the radiocarpal and midcarpal portals. We present a modified method using radiocarpal portals only for arthroscopically excising dorsal midcarpal ganglion cysts. No extra midcarpal portals are necessary, and the method potentially generates satisfactory results.

Role of serotonin in the lack of sensitization caused by prolonged food deprivation in Aplysia.

Food deprivation may cause neurological dysfunctions including memory impairment. The mollusk Aplysia is a suitable animal model to study prolonged food deprivation-induced memory deficits because it can sustain up to 14 days of food deprivation (14DFD). Sensitization of defensive withdrawal reflexes has been used to illustrate the detrimental effects of 14DFD on memory formation. Under normal feeding conditions (i.e., two days food deprivation, 2DFD), aversive stimuli lead to serotonin (5-HT) release into the hemolymph and neuropil, which mediates sensitization and its cellular correlates including increased excitability of tail sensory neurons (TSNs). Recent studies found that 14DFD prevents both short-term and long-term sensitization, as well as short-term increased excitability of TSNs induced by in vitro aversive training. This study investigated the role of 5-HT in the absence of sensitization and TSN increased excitability under 14DFD. Because 5-HT is synthesized from tryptophan obtained through diet, and its exogeneous application alone induces sensitization and increases TSN excitability, we hypothesized that 1) 5-HT level may be reduced by 14DFD and 2) 5-HT may still induce sensitization and TSN increased excitability in 14DFD animals. Results revealed that 14DFD significantly decreased hemolymph 5-HT level, which may contribute to the lack of sensitization and its cellular correlates, while ganglia 5-HT level was not changed. 5-HT exogenous application induced sensitization in 14DFD Aplysia, albeit smaller than that in 2DFD animals, suggesting that this treatment can only induce partial sensitization in food deprived animals. Under 14DFD, 5-HT increased TSN excitability indistinguishable from that observed under 2DFD. Taken together, these findings characterize 5-HT metabolic deficiency under 14DFD, which may be compensated, at least in part, by 5-HT exogenous application.

CUBITAL TUNNEL SYNDROME DUE TO AN INTRANEURAL GANGLION CYST OF THE ULNAR NERVE.

Cubital tunnel syndrome is the second most common neuropathy of the upper extremity. Cubital tunnel syndrome caused by intraneural ganglion cysts is rare in clinical practice. We present the case of a 71-year-old male patient with a 4-month history of cubital tunnel syndrome of the left elbow due to an intraneural ganglion cyst. After revision of the ulnar nerve and resection of the intraneural cyst nearly complete recovery was achieved within a 5 month follow-up but some sensory deficits of the fifth fingertip. We recommend preoperative ultrasound examination of the cubital tunnel even in cases with clear diagnosis. Ganglion cyst as a cause of cubital tunnel is rare but needs to be diagnosed and treated as soon as possible to prevent irreversible complications.

AN INTRATENDINOUS GANGLION CYST OF THE PATELLAR TENDON: A RARE CAUSE OF ANTERIOR KNEE PAIN.

Ganglion cysts in the knee region can manifest as anterior knee pain. Unlike synovial cysts, these lesions lack synovial epithelial lining and occur secondary to mucoid degeneration of connective tissue because, often in response to chronic irritation and repetitive traumas. However, an intratendinous location is a rare finding. In the knee region, infrapatellar fat pad, the alar folds, and the anterior cruciate ligament are recognized to degenerate into ganglion. There are few case reports describing an involvement of the patellar tendon. We present the clinical case of a 72 years old male patient suffering from anterior knee pain attributed to an intratendinous ganglion cyst of the patellar tendon, obviously after a single traumatic event. After aspiration of the ganglion cyst the patient reported no complaints, and there has been no recurrence during the latest follow-up examination.

Arthroscopic Dorsal Ligamentocapsulodesis in the Treatment of Occult Dorsal Wrist Ganglion Cysts Associated with Scapholunate Instability: Surgical Technique and Preliminary Clinical Results.

Background: This study aimed to evaluate our preliminary results and experience with the arthroscopic dorsal ligamentocapsulodesis in managing occult dorsal wrist ganglion cysts (ODGCs) associated with scapholunate (SL) instability. Methods: All patients who underwent arthroscopic dorsal ligamentocapsulodesis due to an ODGC with concomitant SL ligament tear were retrospectively reviewed. In addition to demographic data and length of follow-up, outcomes data that included range of motion, grip strength, modified Mayo wrist score (MMWS), complications and radiographs were collected. Results: The study included 18 patients (18 wrists; 10 female and 8 male). The mean age was 32 years (range: 19-48) and the mean follow-up was 34 months (range: 24-48). The mean preoperative extension deficit decreased from 5.5° (range: 0°-20°) to 2.7° (range: 0°-15°) at the final follow-up (p = 0.004). The mean preoperative flexion deficits decreased from 4.4° (range: 0°-15°) to 2.2° (range: 0°-10°) postoperatively (p = 0.003). The mean hand grip strength significantly increased from 27.7 kg (range: 22-36) to 38.3 kg (range: 31-46) at the final follow-up assessment (p < 0.001). The mean MMWS improved from 46 (range: 25-65) pre-operatively to 91 (range: 70-100) at the final follow-up (p = 0.0002). No major intra- or postoperative complications were observed. Conclusions: SL instability may have an important role in the aetiology of ODGCs, and arthroscopic dorsal ligamentocapsulodesis can provide pain relief and functional improvement without recurrence at the short- to mid-term follow-up in the treatment of ODGCs. Level of Evidence: Level IV (Therapeutic).

General Morphology of the Mammalian Carotid Body.

The carotid body (CB) is the main peripheral arterial chemoreceptor that registers the levels of pO2, pCO2 and pH in the blood and responds to their changes by regulating breathing. It is strategically located in the bifurcation of each common carotid artery. The organ consists of "glomera" composed of two cell types, glomus and sustentacular cells, interspersed by blood vessels and nerve bundles and separated by connective tissue. The neuron-like glomus or type I cells are considered as the chemosensory cells of the CB. They contain numerous cytoplasmic organelles and dense-cored vesicles that store and release neurotransmitters. They also form both conventional chemical and electrical synapses between each other and are contacted by peripheral nerve endings of petrosal ganglion neurons. The glomus cells are dually innervated by both sensory nerve fibers through the carotid sinus nerve and autonomic fibers of sympathetic origin via the ganglioglomerular nerve. The parasympathetic efferent innervation is relayed by vasomotor fibers of ganglion cells located around or inside the CB. The glial-like sustentacular or type II cells are regarded to be supporting cells although they sustain physiologic neurogenesis in the adult CB and are thus supposed to be progenitor cells as well. The CB is a highly vascularized organ and its intraorgan hemodynamics possibly plays a role in the process of chemoreception.

[Rupture of the flexor carpi radialis tendon after corticosteroid injection of a ganglion cyst]. / Peesruptuur na injectie van corticosteroïden in ganglioncyste.

BACKGROUND: Although corticosteroid injections are frequently used in practice to treat tendinopathies, there are many adverse effects. CASE DESCRIPTION: A 62-year-old woman received an aspiration and corticosteroid injection of a ganglion on the volar side of the left wrist. A few weeks later, she presented with severe pain and loss of function of the left wrist. On physical examination, here was a notable swelling with hematoma formation, along the course of the flexor carpi radialis. An MRI confirmed complete rupture of the flexor carpi radialis (FCR) tendon. She was treated non operatively with analgesics and a protective brace. During final check-up minimal loss of function was seen. CONCLUSION: Cautiousness and judicious restraint are imperative when considering corticosteroid infiltrations targeting a volar ganglion at the level of the FCR. Aspiration combined with corticosteroid infiltration is not recommended for patients exhibiting (subclinical) STT-/CMC-1 osteoarthritis, as it may cause FCR tendon ruptures.

Digital mucous cysts of the finger without osteoarthritis: optimizing outcome of long needle trajectory aspiration and injection.

Digital mucous cysts are common, benign and highly recurrent tumors of the distal interphalangeal joints of the fingers and often associated with osteoarthritis. Multiple treatment modalities have been described, but still no consensus is stated. In the absence of degenerative changes, we promote a novel non-surgical approach. The aim of this study was to examine all patients with digital mucous cysts without underlying osteoarthritis, undergoing this injection technique and to assess outcome and complications of this procedure. This was a single center study (2018-2019) of 17 patients who received a long needle trajectory aspiration and injection for treatment of digital mucous cysts. Exclusion criteria were prior surgical treatment, post-traumatic cyst formation and the presence of radiographic distal interphalangeal joint osteophytosis. A total of 15 patients were found eligible for inclusion. The patient reports were retrospectively analyzed with a follow-up of 6 months. The primary study outcome was resolution of the cyst; secondary outcomes were complications of the procedure. Twelve (80%) resolved completely and three (20%) had limited local recurrence at 6 months. No complications were reported. None of the patients with limited recurrence desired further treatment. We believe that this technique offers a non-invasive, low-cost treatment option for digital mucous cysts, particularly in the subset of patients with ample evidence of degenerative articular changes in the distal interphalangeal joint. The described technique can be performed in an office-based setting and avoids typical surgical as well as aspiration-associated complications.

Tarsal tunnel ganglion cyst: intraneural or extraneural site?

Intraneural ganglion cysts are very uncommon lesions, whose diagnosis has increased since the articular theory and the description of the MRI findings were established. We present a case report of a 59-year-old man with symptoms of tarsal tunnel syndrome. Foot and ankle MRI demonstrated the presence of an intraneural cystic lesion in the posterior tibial neve and its connection with the subtalar joint through an articular branch. The identification of the specific radiological signs like the «signet ring sign¼ allowed establishing an adequate preoperative diagnosis, differentiating it from an extraneural lesion and facilitating the articular disconnection of the nerve branch during surgery.

Intraneural ganglion cyst of the peroneal nerve occurring after coronavirus disease-19 vaccination: A case report.

Ganglion cysts are relatively common, but intraneural ganglion cysts (INGCs) within peripheral nerves are rare and poorly understood. We present the case of a 58-year-old woman who presented with acute right-foot drop. She experienced acute knee pain radiating from the lateral leg to the dorsal foot two days after the first coronavirus disease-19 (COVID-19) vaccination (BNT162b2, Pfizer-BioNTech). She had no history of trauma or medication use. Two weeks after the onset of symptoms, she developed a dorsiflexor weakness of the right foot (Medical Research Council grade, poor). The weakness worsened to a "trace" grade despite providing conservative management for one month. Ultrasonography revealed a fusiform echolucent structure within the course of the right common peroneal nerve around the fibular head. Magnetic resonance imaging revealed multiple intraneural cysts within the right common peroneal nerve. Nerve conduction and electromyographic studies revealed multiphasic motor unit action potentials accompanied by abnormal spontaneous activities in the innervated muscles, along with axonal degeneration of the deep peroneal nerves. Surgical removal of the cyst was performed, and the patient's symptoms gradually improved. Pathological examination revealed a cystic structure containing mucinous or gelatinous fluid and lined with flattened or cuboidal cells. The clinical course and sequential electromyographic findings relevant to this symptomatic cyst were temporally related to the vaccination date. The present case suggests that INGC-induced peroneal palsy is a possible complication after COVID-19 vaccination.

Enteric neurospheres retain the capacity to assemble neural networks with motile and metamorphic gliocytes and ganglia.

BACKGROUND: Neurosphere medium (NSM) and self-renewal medium (SRM) were widely used to isolate enteric neural stem cells (ENSCs) in the form of neurospheres. ENSCs or their neurosphere forms were neurogenic and gliogenic, but the compelling evidence for their capacity of assembling enteric neural networks remained lacking, raising the question of their aptitude for rebuilding the enteric nervous system (ENS) in ENSC therapeutics. It prompted us to explore an effective culture protocol or strategy for assembling ENS networks, which might also be employed as an in vitro model to simplify the biological complexity of ENS embedded in gut walls. METHODS: NSM and SRM were examined for their capacity to generate neurospheres in mass culture of dispersed murine fetal enterocytes at serially diluted doses and assemble enteric neural networks in two- and three-dimensional cell culture systems and ex vivo on gut explants. Time-lapse microphotography was employed to capture cell activities of assembled neural networks. Neurosphere transplantation was performed via rectal submucosal injection. RESULTS: In mass culture of dispersed enterocytes, NSM generated discrete units of neurospheres, whereas SRM promoted neural network assembly with neurospheres akin to enteric ganglia. Both were highly affected by seeding cell doses. SRM had similar ENSC mitosis-driving capacity to NSM, but was superior in driving ENSC differentiation in company with heightened ENSC apoptosis. Enteric neurospheres were motile, capable of merging together. It argued against their clonal entities. When nurtured in SRM, enteric neurospheres proved competent to assemble neural networks on two-dimensional coverslips, in three-dimensional hydrogels and on gut explants. In the course of neural network assembly from enteric neurospheres, neurite extension was preceded by migratory expansion of gliocytes. Assembled neural networks contained motile ganglia and gliocytes that constantly underwent shapeshift. Neurospheres transplanted into rectal submucosa might reconstitute myenteric plexuses of recipients' rectum. CONCLUSION: Enteric neurospheres mass-produced in NSM might assemble neural networks in SRM-immersed two- or three-dimensional environments and on gut explants, and reconstitute myenteric plexuses of the colon after rectal submucosal transplantation. Our results also shed first light on the dynamic entity of ENS and open the experimental avenues to explore cellular activities of ENS and facilitate ENS demystification.