This is the first global report of a successful case of lenvatinib treatment for a rare sebaceous carcinoma originating in the external auditory canal. The patient experienced local recurrence and pulmonary metastasis despite undergoing surgery and radiotherapy. Initial chemotherapy combined with immune checkpoint inhibitors achieved short-term stability, but the disease eventually progressed. Genetic testing revealed an Fibroblast growth factor receptor 2 (FGFR2) mutation, leading to a switch to targeted therapy with lenvatinib combined with capecitabine, demonstrating the value of targeted therapy in the management of rare, refractory sebaceous carcinoma.

The purpose of this study was to determine the correlation between cytology and histology in the diagnosis of canine tympanokeratoma. Dogs that had a middle ear aspiration cytology via otoendoscope-guided myringotomy and a histology of the tympanic bulla content sampled following total ear canal ablation with lateral bulla osteotomy between 2010 and 2024 in one hospital were retrospectively examined. Cytological diagnosis of tympanokeratoma was considered when the sample contained a majority of corneocytes. Thirty-seven ears with a pathological diagnosis of either tympanokeratoma (31/37) or nontympanokeratoma otitis media (6/37) were chosen. Cytology had an accuracy of 78%, a sensitivity of 74%, and a specificity of 100% for diagnosing tympanokeratoma, with negative and positive predictive values of 43 and 100%, respectively. Among ears with histologically confirmed tympanokeratoma, imaging showed lysis and expansion of the tympanic bulla in 45.2 and 12.9%, respectively. Otoendoscopy showed a mass in the horizontal ear canal in 22.6%. Dense opaque pearly yellowish material was sampled from the tympanic cavity in 45.2%. Middle ear aspiration cytology via otoendoscope-guided myringotomy is a useful tool for diagnosing tympanokeratoma and is highly reliable in cases of positive outcomes. However, its capacity to rule out the condition is limited, particularly in infected ears.

This study aimed to identify predictors of surgical success in patients with non-cholesteatomatous chronic otitis media (COM) undergoing endoscopic tympanoplasty. Patients who underwent endoscopic tympanoplasty for COM without cholesteatoma between January 2012 and December 2023 were retrospectively reviewed. Primary outcomes were graft success and the combined outcome of intact tympanic membrane with hearing (postoperative air-bone gap [ABG] < 15 dB). Descriptive statistics and logistic regression analyses were used to identify predictors. Among 301 cases, graft integrity at 12 months was achieved in 82.4%. The mean ABG improved from 22.8 to 9.8 dB. The use of perichondrium (OR = 3.67; 95% CI, 1.22-15.88) and cartilage (OR = 2.31; 95% CI, 1.02-5.81) grafts was significantly associated with higher rates of graft take compared with temporalis fascia. Predictors of reduced graft success included untreated rhinitis (OR = 0.25; 95% CI, 0.07-0.81), persistent otorrhea (OR = 0.18; 95% CI, 0.03-0.97), and inferior external auditory canal bony overhang (OR = 0.17; 95% CI, 0.04-0.79). Considering combined graft take and hearing outcomes, preoperative ABG ≤ 30 dB was a significant predictor of favorable outcomes, whereas untreated rhinitis, persistent otorrhea, and middle ear swelling were negative predictors. Endoscopic tympanoplasty is an effective treatment for COM without cholesteatoma. Surgical graft success was enhanced by selecting durable graft materials, particularly cartilage or perichondrium, maintaining a dry ear, controlling rhinitis, and addressing anatomical challenges such as canal overhangs. Both graft uptake and hearing improvement were strongly influenced by preoperative ABG and nasal and middle ear conditions.

The objective of this study was to compare graft outcomes and complications of myringoplasty among external auditory canal packing (EAC) with Nasopore, blood on the graft surface, and no EAC packing. Patients with chronic perforation were randomly allocated to the EAC packing with Nasopore group (n = 40), blood on the graft surface group (n = 40), or no EAC packing group (n = 40). All patients underwent endoscopic cartilage myringoplasty with middle ear packing. Self-reported subjective symptoms, graft success, audiometric outcomes, and complications were evaluated at up to 24 months postoperatively. In total, 120 patients were randomized into the study groups. The rates of aural fullness were 79.49% in the EAC packing group, 28.95% in the blood on the graft surface group, and 21.05% in the no EAC packing group ( P < 0.001). At 24 months postoperatively, the graft success rates were 79.49% in the EAC packing group, 94.74% in the blood group, and 81.58% in the no EAC packing group, with a statistically significant difference among the groups ( P < 0.001). Pairwise comparisons demonstrated a significant difference between the EAC packing and blood on the graft surface groups ( P < 0.05), but no significant difference between the EAC packing and no EAC packing groups ( P > 0.05) or between the blood on the graft surface and no EAC packing groups ( P > 0.05). When outcomes were stratified by perforation size, the blood on the graft surface consistently demonstrated higher graft success rates compared with the EAC packing and no EAC packing groups for medium perforation. No significant differences were observed among the groups in terms of preoperative or postoperative mean air or bone conduction pure-tone averages, air-bone gaps, or air-bone gap closure. The incidences of myringitis were 5.13% in the EAC with Nasopore packing group, 7.89% in the blood on the graft surface group, and 28.95% in the no EAC packing group ( P < 0.001). Autologous blood on the graft surface yielded higher graft success rates than EAC packing following cartilage underlay myringoplasty with middle ear packing, while there was no statistically significant difference between blood and no packing groups. Nevertheless, audiometric outcomes were comparable among these 3 arms.

Congenital unilateral conductive hearing impairment alters auditory white matter tract connections of the brain. Unilateral conductive hearing loss has negative effects on speech perception in noise and sound localization ability. This study examines auditory white matter tracts in a rat model with surgically induced unilateral ear canal atresia, compared with controls. Twelve-month euthanized rats, 7 with left-sided surgically created ear canal atresia (UCA) and 4 controls, were scanned in a 9.4 T MRI scanner for animal research purposes. Diffusion-weighted images were acquired. Two different methods for probabilistic fiber tracking were used. Fractional anisotropy (FA) was calculated from whole brains and from tracts between defined auditory regions of interest. Both methods of fiber tracking show significantly higher global FA in rats with UCA. Within-group comparisons in UCA show higher FA on the hearing side between the cochlear nucleus and inferior colliculus, compared with the side of hearing loss, while in controls, there was no asymmetry. Lower FA was also found between the medial geniculate complex and the auditory cortex on the left side than on the right in UCA, in contrast to controls, where there was no difference between the hemispheres. The asymmetry found in UCA indicates alterations of auditory white matter tracts as a response to asymmetric hearing, partly confirming previous findings in experiments on ferrets.

Investigating the Neural Origins of Ear-EEG: A Correlation Study Using Scalp EEG Source Reconstruction.

Otomycosis is one of the common health problems encountered in the day-to-day ENT practice. The infection was present globally, with the prevalence of otomycosis between 9% and 30% in different world populations. The otomycosis diagnosis is primarily based on the patient’s history, clinical presentation, and the otoscopic examination of the external auditory canal and the tympanic membrane. Although several treatment options were available, none of them were found to be effective in curing the disease completely. So the study’s main aim is to compare the effectiveness of clotrimazole and fluconazole in treating otomycosis. This quasi-experimental study was conducted in the Department of ENT in a tertiary care centre, Chengalpattu, Kancheepuram District, Tamil Nadu, India. The study was conducted for 18 months, from July 2023 to December 2024. After the initial assessment, all the patients were divided into two groups. All the patients who received 1% clotrimazole ear drop were in Group A , whereas those in Group B were who received 0.3% fluconazole ear drops for 13 days. The patients were followed on the 3rd day, the 1st week, and at the end of the 2nd week and assessed. A total of 60 patients participated in the study; 35% were found to be between 31 and 40 years old, and the female patients outnumbered the male patients. 0.3% Fluconazole (Group A) showed a significant reduction in symptoms such as ear discharge, otalgia, aural block and tinnitus signs such as cartilaginous canal oedema, cartilaginous canal erythema, bony canal oedema, bony canal erythema, tympanic membrane congestion, spore, the granulation and, otitis externa than the patients who took 1% clotrimazole ear drops (Group A). Group B also showed a reduction of the fungal colonies compared to the patients in Group A; the study also showed that 80% of the patients in Group B were cured entirely compared to 60% in Group A. Our study showed that the 0.3% fluconazole ear drops reduced the fungal colonies and signs and symptoms of otomycosis more than 1% clotrimazole ear drops. The study recommends using 0.3% fluconazole ear drops among patients with otomycosis.

Current State of Button Battery Ingestion Injuries.

Petroclival and temporal bone meningiomas are rare neoplasms that mimic vestibular schwannomas in presentation. However, surgical approaches for their resection are often more complex, largely due to the necessity of resecting pathologic dura. Although several classification and staging systems for petroclival meningiomas have been proposed, they are rarely cited and none are reliably correlated with surgical outcomes. We present a descriptive framework and hypothesize that it is predictive of surgical outcomes. Medical records of patients seen at a tertiary referral center with a diagnosis of petroclival meningioma were reviewed. Patients were stratified into four tiers: tier 1, meningioma confined to internal auditory canal (IAC) only; tier 2, meningioma confined to cerebellopontine angle (CPA) only; tier 3, meningioma involving CPA and IAC; and tier 4, meningioma involving cavernous sinus, internal carotid artery or jugular bulb, or crossing midline. Tier 4 was subdivided into 4A (no carotid involvement) and 4B (carotid involvement). Outcomes of observation, radiation, and surgery were analyzed. Of 64 qualified patients, tier 2 was most commonly encountered (41%); the remainder of patients were classified as tier 1, 3, and 4 (3%, 33%, 23%). Among patients indicated for resection, combined petrosal approach was utilized in 64% of cases. Simpson grade of resection, complication rate, and rate of residual/recurrent tumor were statistically significantly associated with tumor tier. Tier and postoperative House-Brackmann score showed no significant correlation. The proposed framework demonstrates the potential clinical utility of an outcome-predictive staging system, helping to guide surgeon and patient expectations.

Molecular features of external Auditory Canal cholesteatoma by microbial metagenomic sequencing.

Inner ear malformations can cause abnormal communication between the inner ear and subarachnoid space, leading to otogenic cerebrospinal fluid (CSF) leakage and subsequent bacterial meningitis. Persistent leakage may result in recurrent meningitis, which is associated with neurological sequelae and poor prognosis; thus, early diagnosis and surgical intervention are essential. Various surgical strategies have been reported, commonly termed middle ear obliteration and inner ear obliteration. However, their definitions remain ambiguous, and techniques vary widely in approach and effectiveness. This study describes 2 pediatric cases of incomplete partition type I (IP-I) malformation complicated by recurrent meningitis that were treated with translabyrinthine fistula closure via the lateral semicircular canal, a form of inner ear obliteration. Both patients exhibited high vestibular CSF pressure due to hypoplasia of the internal auditory canal fundus. Patient 1 had undergone 4 previous window closure surgeries elsewhere without success, whereas Patient 2 had no residual hearing and required prompt management. In both cases, the fistula was directly identified and sealed with a three-layer construct under direct visualization, allowing secure closure. Postoperative follow-up revealed no recurrence of meningitis for >8 years in Case 1 and more than 1 year in Case 2, without complications. This technique may represent a reasonable treatment option for controlling CSF leakage in severe inner ear malformations, including cases refractory to conventional treatments, even at the cost of sacrificing inner ear function. Using 2 representative pediatric cases, this study presents a case-based review that clarifies the classification, indications, and limitations of current surgical strategies for otogenic CSF leakage associated with inner ear malformations.

Otitis externa (OE) represents a common clinical problem in dogs. Allergic dogs exhibit reduced diversity of the otic microbiota, and inflammation-induced changes in the ear canal microenvironment result in a further decline in microbial biodiversity. Probiotics have demonstrated efficacy in certain dermatological conditions, including atopic dermatitis, which is, in turn, the leading primary cause of OE in dogs. To evaluate the efficacy of probiotic-based ear drops in controlling clinical signs related to erythroceruminous non-infected OE in dogs. Thirty-seven privately owned dogs with non-infected OE. Dogs received probiotic-based ear drops topically every 48 h for 28 days, in accordance with the manufacturer's instructions. Assessments were performed at enrolment (Day [D]0), D14 and D28, including cytological evaluation of ear discharge, pruritus intensity (PVAS, pruritis Visual Analogue Scale), severity of otic lesions (OTIS3, 0-3 Otitis Index Score) and a quality-of-life survey (QoL). At enrolment (D0), mean OTIS3 and PVAS scores for all included animals were 5.11 ± 1.20 and 4.93 ± 1.51, respectively. Both scores decreased significantly by D28, to 1.66 ± 1.75 and 2.09 ± 2.03, respectively. Clinical improvement was evident regardless of concomitant medication use or the type of micro-organism's overgrowth observed during the initial cytological assessment. Owner-reported QoL improved in 80% of the dogs. These probiotic-based ear drops may be a useful adjunctive therapy in cases of canine non-infectious erythroceruminous OE.

Accurate imaging recognition of jugular bulb (JB) variants is essential for skull-base surgical planning and prevention of intraoperative vascular injury. This prospective study aimed to determine the prevalence and classification of JB variants using high-resolution CT (HRCT) temporal bone and CT head and neck angiography (CTA), evaluate the utility of standardized radiologic landmarks for consistent reporting and communication between radiologists and surgeons, and to assess associations with clinical symptoms and condylar canal size. A prospective observational study was conducted on 200 patients, including 100 undergoing HRCT temporal bone and 100 undergoing CTA performed for non-otologic indications. JB variants were classified using the Manjila-Semaan grading system based on internal auditory canal (IAC) and posterior semicircular canal (PSC) landmarks. Distances from the JB to key otologic structures, including the PSC, IAC, round window, basal turn of the cochlea, and vestibular aqueduct were measured. Associations with condylar canal size and clinical symptoms were analyzed using appropriate nonparametric and categorical statistical tests. Type 2 JBs were the most common, while high-positioned bulbs (Types 3 and 4) accounted for approximately 25%. Dehiscent bulbs were identified in 10% of cases. HRJB prevalence varied widely (7-32%) depending on the anatomical landmark used. No significant associations were found with age, sex or clinical symptoms. Condylar canal size demonstrated no significant correlation with JB size. JB variants, particularly high-riding and dehiscent forms, appear to be more prevalent than previously recognized. Standardized classification using IAC and PSC landmarks on multiplanar CT may improve reporting uniformity and facilitate communication between radiologists and skull-base surgeons. This prospective study also suggests that HRJB does not necessarily reflect compensatory enlargement of emissary venous channels and may instead represent focal venous remodeling independent of condylar canal size. Recognition of these variants is therefore important in preoperative planning to anticipate potential venous hemorrhage during skull-base surgery.

Distortion product otoacoustic emission (DPOAE) magnitudes measured in the ear canal in response to a range of primary stimulus levels as growth functions (GFs) may be useful for assessing cochlear non-linearity, predicting behavioral audiometric thresholds, estimating loudness perception, and differentiating types of cochlear pathology. A variety of stimulation schemes have been proposed, and GF shapes differ depending on the stimulation scheme used. A clearer understanding of the relationships between stimuli, GFs, cochlear non-linearities, and cochlear health is important for maximizing the diagnostic potential of DPOAEs. Latent growth modeling, a technique within the structural equation modeling framework, can provide insight into the relationships between observed (e.g., GFs) and unobserved latent variables (e.g., cochlear non-linearities). We describe a latent growth model for characterizing GFs with a generalized logistic function representing the latent non-linearity, coupled with a generalized linear regression model appropriate for fitting GFs with varying signal-to-noise ratios (SNRs). The model was applied to GF data from twelve young adult ears (9 female, 3 male). The resulting fits inferred the shape of the underlying non-linearity and also quantified standard GF characteristics such as slope, threshold, and inflection points. Data from participants, along with Monte Carlo simulations, demonstrate that this fitting method performs well under low SNR conditions and accurately predicts DPOAE magnitudes at low stimulus levels. This report establishes a robust method for characterizing GFs, supporting the long-term goal of applying the method in future studies of the relationships between acoustic stimuli, GFs, cochlear non-linearities, and cochlear health.

This systematic review of clinical practice guidelines summarizes key recommendations and interventions related to the prevention, diagnosis, and management of acute otitis externa. The interventions identified in this review will contribute to the development of the World Health Organization (WHO) Package of Ear and Hearing Care Interventions (PEHCI). We searched PubMed, CINAHL, Clinical Key, and TRIP databases to identify clinical practice guidelines related to otitis externa. We hand-searched professional organization websites to identify additional clinical practice guidelines that were not identified from the database search or that were published in languages other than English (Spanish, French, Chinese, and Russian). Publications were required to be clinical practice guidelines and published between 2014 and 2024. All review processes were performed by 2 independent reviewers, including the quality assessment with the AGREE II tool. We identified 6 clinical practice guidelines, 4 of which met our prespecified inclusion criteria based on the AGREE II assessment. The 4 included guidelines were published in the United States, Colombia, and 2 in Russia, and in 3 languages. Key interventions focused on prevention (avoiding injury, keeping the ear canal dry, and timely cerumen management), patient education and counseling, comprehensive diagnostic assessment, and pharmaceutical interventions and ear cleaning. The clinical practice guidelines identified key interventions related to the prevention, diagnosis, and management of otitis externa. These interventions will be used to inform the development of the PEHCI, which will identify priority ear and hearing care interventions that can be integrated into national health services packages and policies.

In maxillofacial surgery, accessing the mandibular condyle is a contested topic. Whilst retro-auricular approaches are considered to be protective of the facial nerve, the distance from dissection to nerve has not been verified. Dissection of 29 cadaveric head specimens was carried out using a retro-auricular approach. Three measurements were made: (a) from nerve to the inferior edge of the cartilaginous external acoustic meatus, (b) thickness of tissue laterally between dissection and nerve, and (c) thickness of tissue vertically between inferior limit of dissection and nerve. Intra-class correlation co-efficient (ICC) was used to assess inter-observer reliability. The mean distance from the external acoustic meatus was 14.28 mm (ICC = 0.59). Inferior tissue thickness averaged 9.70 mm (ICC = 0.42), and lateral tissue thickness averaged 7.17 mm (ICC = 0.59). Inferior tissue thickness demonstrated the greatest inter-specimen standard deviation (3.09 mm) and lowest individual specimen measurements (0.99 mm). The retro-auricular approach remains safe for surgical access to the mandibular condyle. However, care should be taken of the inferior extent of the dissection once past the external acoustic meatus, particularly when supervising trainees.

Despite effective surgical evacuation, chronic subdural hematoma (cSDH) recurrence rates remain high. Middle meningeal artery (MMA) embolization has emerged as a promising adjunct significantly reducing recurrence rates but adding procedural risk, logistical complexity, and cost. Thus, single-stage cSDH evacuation with direct surgical MMA occlusion through a single pterional/frontotemporal burr hole could offer a practical alternative. This study assesses the applicability of this approach on routine preoperative imaging and evaluates both neuronavigation-guided and landmark-based localization of the MMA bifurcation. In this single-center study, preoperative noncontrast cranial computed tomography scans of patients undergoing burr hole trepanation for cSDH were analyzed. We assessed osseous MMA anatomy, visibility, and dominance of the MMA bifurcation; its spatial relationship to the cSDH; and distances from 3 external craniometric landmarks [Stephanion, Bregma, and external auditory canal (EAC)-zygomatic root plane]. Twenty patients with 26 cSDHs were included. A distinct osseous groove indicating the MMA bifurcation was identifiable in all cases (100%). The bifurcation overlapped with the hematoma in 18/26 (75%) and projected onto the region of maximal thickness in 5/26 (21%). Mean craniocaudal and anteroposterior distances from the Stephanion to the bifurcation were 27.3 ± 12.3 mm and 8.8 ± 5.5 mm; from the Bregma 113.9 ± 18.2 mm and 16.1 ± 8.6 mm, respectively. In the sagittal plane, the mean perpendicular distance from the EAC-zygomatic line to the bifurcation was 52.4 ± 10.8 mm, and the mean distance from EAC to the MMA bifurcation along this line was 29.9 ± 10.8 mm. Anatomic localization of the MMA bifurcation using standard noncontrast cranial computed tomography and external craniometric landmarks is feasible. Furthermore, the bifurcation overlaps the hematoma in most patients. These findings support the technical plausibility of surgical MMA occlusion via a strategically placed pterional burr hole (or an additional burr hole for occlusion if no overlap) as a straightforward alternative to endovascular embolization in selected patients with cSDH.

Accurate diagnosis of eardrum abnormalities is pivotal for effectively managing various ear conditions. Otoscopy, a non-invasive diagnostic procedure, provides detailed views of the ear canal and eardrum to identify pathologies such as otitis media, tympanic membrane perforations, and other abnormalities. Despite advancements, classifying otoscopy images remains challenging due to lighting variations, motion blur, and diverse abnormalities, exacerbated by limited labeled datasets and subjective assessments. A significant barrier to accurate diagnosis is the lack of an objective evaluation method for eardrums, such as machine learning techniques to classify images as normal or abnormal. Moreover, when processing otoscopy videos, traditional approaches require extensive manual expertise to select representative frames for analysis. This study investigates the efficacy of artificial image augmentation using StyleGAN3 to enhance otoscopy image classification accuracy. Augmented datasets comprising artificial and composite otoscopy images were used to train and validate a ResNet-101 model. A total of 816 artificial and 816 composite images (250-Effusion, 340-Normal, 113-Perforation, and 113-Tympanosclerosis) and 80,685 classic augmented images (24651-Effusion, 33660-Normal, 11187-Perforation, and 11187-Tympanosclerosis) were used. Results demonstrate that integrating StyleGAN3-generated synthetic images significantly improves classification performance. Our approach achieved a mean test accuracy of 0.95 ± 0.03 and an F1-score of 0.96 ± 0.02, surpassing those of traditional augmentation methods, while representing an optimistic upper-bound scenario. In contrast, without any augmentation, the accuracy and F1-score are 0.82 ± 0.03 and 0.78 ± 0.02, respectively, and with classic augmentations, they are 0.87 ± 0.02 and 0.85 ± 0.02, respectively. These findings underscore the potential of GAN-based augmentation to bolster eardrum image classification systems and address challenges in diagnostic accuracy.

We employ the Hamiltonian Monte Carlo (HMC) algorithm to estimate model parameters and quantify their uncertainties in a fractional-order lumped-element model of the human ear in a Bayesian inference framework. The model, originally developed by Naghibolhosseini and Long (2018), incorporates fractional-order elements to capture viscoelastic memory effects in ear tissues that otherwise cannot adequately be represented via conventional integer-order models. Using previously optimized model parameters to construct informative priors, we perform Bayesian parameter estimation via the No-U-Turn Sampler (NUTS) implementation. From the inferred posterior distributions, we compute the model's outer-middle ear gain (OMEG) and validate predictions against experimental OMEG derived from DPOAE measurements. Additionally, we compare stapes velocity transfer functions and ear canal pressure gain with established experimental and computational literature. HMC sampling yields well-convergent posterior distributions for all parameters, centered near original optimized values with uncertainty quantified through credible intervals. The posterior predictive OMEG frequency response closely matches the experimental OMEG measurements. Interestingly, the Bayesian-derived parameter sets correctly exhibit stapes velocity resonances near 1kHz and ear canal pressure gain peaks between 2.5 and 4kHz, with amplification ranging from 4 to 12dB, consistent with cadaveric experimental measurements and existing computational models. The model demonstrates a minimal intersubject variability while capturing realistic biological variations within experimentally reported ranges. The present Bayesian HMC simulation approach then provides a robust uncertainty quantification for fractional-order ear model parameter inference, maintaining physiologically consistent predictions across multiple validation datasets. Hence, the proposed framework enhances the model's credibility by establishing a firm foundation for further developing probabilistic diagnostic tools for hearing assessment in the future.

Mammomonogamus ierei is a nasal nematode of domestic cats, for which the life cycle and route of infection have remained unknown. Experimental oral infections have historically failed, leading to speculation regarding the involvement of an intermediate host and uncertainty about transmission pathways. The aim of this study was to determine the route of infection of M. ierei in domestic cats. Twenty kittens (6-12weeks old) were exposed to infective third-stage larvae (L3) via six routes: per os (n = 3), oral mucosa (n = 3), nasal mucosa (n = 3), subcutaneous (n = 3), percutaneous (abdominal region) (n = 2), external auditory canal (n = 2), and an unexposed control group (n = 4). Kittens were randomized across litters to minimize litter-associated effects and monitored using serial fecal examinations for 70days post-inoculation to assess establishment of infection and egg shedding. Motile L3 developed within 9days in culture and exhibited morphometric characteristics consistent with previous descriptions. Two of 20 kittens developed patent M. ierei infections, first shedding eggs 48-51days post-inoculation. Both infected animals belonged to the subcutaneous inoculation group, whereas no infections resulted from other inoculation routes. Mild, transient respiratory signs were observed in some kittens, including one prior to patency. These findings demonstrate, for the first time, a viable route of infection for M. ierei and provide the first experimental evidence of route of transmission for any species within the genus Mammomonogamus. The results suggest a direct life cycle, as infection was established in the absence of an intermediate host, but do not preclude the occurrence of paratenic hosts. Infection via subcutaneous exposure was successfully achieved; however, its relevance under natural conditions remains to be confirmed. This study advances the current understanding of Mammomonogamus biology and may have implications for parasite control and for transmission models of zoonotic species such as Mammomonogamus laryngeus.