Kallmann syndrome (KS) is a rare genetic disorder that refers to the association between hypogonadotropic hypogonadism and anosmia or hyposmia due to abnormal migration of olfactory axons and gonadotropin-releasing hormone-producing neurons. Here, we present a case of a 40-year-old man who presented with psychological problems (emotional disturbance) as the chief complaint. Physical examination revealed gynecomastia, absence of facial and axillary hair, and sparse pubic hair, micropenis, undescended right testicle, low libido and lack of sexual function. A related finding is anosmia, a high-pitched voice. Hormonal analysis revealed hypogonadotropic hypogonadism profile, and chromosomal examination revealed a normal male karyotype. Abdominal ultrasound showed normal organs, and scrotal ultrasound showed an undescended right testicle (UDT) and small testes. Brain MRI revealed pituitary gland hypoplasia and olfactory bulb agenesis. These findings are characteristic of KS. He underwent orchidopexy dextra. He is now on a regular follow-up. Hormone replacement therapy is planned. Thus, besides medical treatments, psychological care is an integral component of the treatment strategy for this patient.

Kallmann syndrome (KS) is a rare genetic disorder manifested by the combination of hypogonadotropic-hypogonadism and olfactory dysfunction. It is usually diagnosed at 14 - 16 years of age due to delayed puberty. However, delays in diagnosis have been reported in a few cases. We presented a 34-year-old man presented with primary infertility as the chief complaint. Physical examination revealed bilateral gynecomastia, Tanner stage 2, and anosmia. Hormonal studies show a hypogonadotropic hypogonadism profile. Genetic testing revealed a normal male karyotype. Abdominal ultrasonography (USG) revealed a small prostate, and testicular USG demonstrated small testicles. Neuroimaging study revealed olfactory bulb agenesis and hypoplasia of the olfactory sulcus. Treatment was done by testosterone replacement therapy, and the patient is now on a regular follow-up. In conclusion, suspected clinical features of KS may guide the diagnosis with comprehensive hormonal and imaging studies. However, the reported patient was diagnosed extremely late.

UNASSIGNED: Rare and mild adverse effects on cranial nerves have been reported after vaccination. Here, we report a singular case of smell and taste disorder associated with tinnitus that occurred after Oxford-AstraZeneca vaccination together with a review of the available literature.
UNASSIGNED: A 76-year-old patient experienced smell disorder, ear fullness and tinnitus 2 days after the first dose of Oxford-AstraZeneca vaccine. The patient then underwent a complete audiological and Ear, Nose and Throat evaluation, nasal endoscopy, Sniffin\'Sticks battery, audiometric test battery, and cerebral magnetic resonance imaging (MRI). The exams revealed hyposmia and bilateral reduction of the volume of the olfactory bulbs (OB). At the follow-up, tinnitus was completely resolved while olfactory dysfunction only partially reduced.
UNASSIGNED: A PubMed search was conducted on olfactory and gustatory dysfunctions after COVID-19 vaccination resulting in four case reports with a total of 10 patients. The main symptoms were hyposmia, parosmia, and dysgeusia developed after 1-9 days from vaccination with complete resolution occurring within 1 month. Notably, none of the considered articles reported reduction of OB volumes at cerebral MRI.
UNASSIGNED: So far, no definitive cause-effect relationship has been established between anti-COVID19 vaccination and otolaryngologic adverse reactions. The persistence of hyposmia in our patient could possibly be explained by the reduction in OB volume, even though also the advanced age of the patient needs to be taken into account. This is a first indication of a cause-effect relation between hyposmia and Covid19 vaccination, even though a more robust study is needed to confirm the autoimmunological mechanisms responsible for these rare adverse reactions. However, it is worth highlighting that benefits of the anti-COVID-19 vaccination clearly outweigh the risk of rare adverse events.

The pathological changes of Alzheimer\'s disease (AD) begin 10-20 years before clinical onset, and it is therefore desirable to identify effective methods for early diagnosis. The nasal mucosa is a target tissue for measuring AD-related biomarkers because the olfactory nerve is the only cranial nerve that is exposed to the external environment. We describe an autopsy case of rapidly advanced juvenile AD (JAD), focusing on the olfactory system. The formation of senile plaques, neurofibrillary tangles (NFTs), and neuropil threads was examined in the temporal cortex, hippocampus, olfactory bulb, and olfactory and respiratory epithelia in the bilateral olfactory clefts. Neurodegenerative changes in the olfactory and respiratory epithelia and the pathological deposition of amyloid β42 (Aβ42) and phosphorylated tau were also examined. As a result, senile plaques, NFTs, and neuropil threads were found in the temporal cortex, hippocampus, and olfactory bulb. NFTs were also found in the olfactory epithelium. Degenerated olfactory cells and their axons stained positive for phosphorylated tau. Supporting cells in the degenerated olfactory epithelium stained positive for Aβ42. In conclusion, pathological biomarkers of AD were expressed in the degenerated olfactory epithelium of this JAD patient. This observation suggests that nasal samples may be useful for the diagnosis of AD.

An altered sense of smell and taste was recognized as one of the most characteristic symptoms of coronavirus infection disease (COVID-19). Despite most patients experiencing a complete functional resolution, there is a 21.3% prevalence of persistent alteration at 12 months after infection. To date, magnetic resonance imaging (MRI) findings in these patients have been variable and not clearly defined. We aimed to clarify radiological alterations of olfactory pathways in patients with long COVID-19 characterized by olfactory dysfunction. A comprehensive review of the English literature was performed by analyzing relevant papers about this topic. A case series was presented: all patients underwent complete otorhinolaryngology evaluation including the Sniffin\' Sticks battery test. A previous diagnosis of SARS-CoV-2 infection was confirmed by positive swabs. The MRIs were acquired using a 3.0T MR scanner with a standardized protocol for olfactory tract analysis. Images were first analysed by a dedicated neuroradiologist and subsequently reviewed and compared with the previous available MRIs. The review of the literature retrieved 25 studies; most cases of olfactory dysfunction more than 3 months after SARS-CoV-2 infection showed olfactory bulb (OB) reduction. Patients in the personal case series had asymmetry and a reduction in the volume of the OB. This evidence was strengthened by the comparison with a previous MRI, where the OBs were normal. The results preliminarily confirmed OB reduction in cases of long COVID-19 with an altered sense of smell. Further studies are needed to clarify the epidemiology, pathophysiology and prognosis.

BACKGROUND: The accessory olfactory bulb (AOB) is the first integrative center of the vomeronasal system (VNS), and the general macroscopic, microscopic, and neurochemical organizational patterns of the AOB differ fundamentally among species. Therefore, the low degree of differentiation observed for the dog AOB is surprising. As the artificial selection pressure exerted on domestic dogs has been suggested to play a key role in the involution of the dog VNS, a wild canid, such as the fox, represents a useful model for studying the hypothetical effects of domestication on the AOB morphology.
METHODS: A comprehensive histological, lectin-histochemical, and immunohistochemical study of the fox AOB was performed. Anti-Gαo and anti-Gαi2 antibodies were particularly useful, as they label the transduction cascade of the vomeronasal receptor types 1 (V1R) and 2 (V2R), respectively. Other employed antibodies included those against proteins such as microtubule-associated protein 2 (MAP-2), tubulin, glial fibrillary acidic protein, growth-associated protein 43 (GAP-43), olfactory marker protein (OMP), calbindin, and calretinin.
RESULTS: The cytoarchitecture of the fox AOB showed a clear lamination, with neatly differentiated layers; a highly developed glomerular layer, rich in periglomerular cells; and large inner cell and granular layers. The immunolabeling of Gαi2, OMP, and GAP-43 delineated the outer layers, whereas Gαo and MAP-2 immunolabeling defined the inner layers. MAP-2 characterized the somas of AOB principal cells and their dendritic trees. Anti-calbindin and anti-calretinin antibodies discriminated neural subpopulations in both the mitral-plexiform layer and the granular cell layer, and the lectin Ulex europeus agglutinin I (UEA-I) showed selectivity for the AOB and the vomeronasal nerves.
CONCLUSIONS: The fox AOB presents unique characteristics and a higher degree of morphological development compared with the dog AOB. The comparatively complex neural basis for semiochemical information processing in the fox compared with that observed in dogs suggests loss of AOB anatomical complexity during the evolutionary history of dogs and opens a new avenue of research for studying the effects of domestication on brain structures.

OBJECTIVE: Olfactory neuroblastoma (ONB) is a rare malignant tumor arising in the upper nasal cleft. Rarely, ONB may originate in ectopic sites and the impact of this on prognosis and treatment strategies continues to be debated.
METHODS: A retrospective analysis was undertaken of patients with ectopic ONB treated between 2000 and 2020 in a tertiary-care referral center for skull base tumors. Three patients were included in this analysis: a 37-year-old woman with ONB arising from the bulla ethmoidalis; a 28-year-old man with inappropriate secretion of antidiuretic hormone caused by a maxillary sinus ONB; and a 41-year-old man with lacrimal sac ONB. Preoperative workup, surgical approach, adjuvant treatments and postoperative surveillance were analyzed. Relevant literature published between 2000 and January 2021 was fully reviewed to investigate oncologic outcomes and delineate the standard of care for such rare tumors.
RESULTS: All patients were treated via endoscopic endonasal resection with radical intent, followed by adjuvant treatments when required. No recurrences of disease were observed after a mean follow-up time of 32 months (range, 12-60 months). Data emerging from the literature suggest that a multidisciplinary treatment approach, including free-margins surgical resection followed by adjuvant radiotherapy or radiochemotherapy, is recommended. Olfactory bulb and dura preservation should be attempted whenever feasible.
CONCLUSIONS: Endoscopic endonasal surgery should be preferred, when possible, to achieve complete excision to minimize patients\' morbidity. The ectopic site of origin affects prognosis and should be considered when selecting the appropriate multimodal treatment strategy.

We report the case of a 49-year-old female patient who suffered from anosmia following an apparently mild head trauma when bumping into a door at her home. She reported no other accompanying symptoms after the injury that day. Olfactory function was completely lost, which was noted the day after the trauma. Gustatory function remained normal. Magnetic resonance imaging indicated lesions/bleeding in the right frontal lobe and in the area of the olfactory sulcus/bulb. The present case indicates that in case of apparently mild head trauma with anosmia, an MRI scan of the head should be performed because of suspect brain damage. This case also points to the deeper question how to gauge severity of head trauma.

Coronavirus Disease-19 (COVID-19) has been in a global pandemic currently and relating symptoms were reported variously around the world. We reported a previously healthy man of COVID-19 presenting with anosmia as the obvious symptom with relevant radiological findings on brain magnetic resonance imaging.

In mammals, the accessory olfactory or vomeronasal system exhibits a wide variety of anatomical arrangements. In caviomorph rodents, the accessory olfactory bulb (AOB) exhibits a dichotomic conformation, in which two subdomains, the anterior (aAOB) and the posterior (pAOB), can be readily distinguished. Interestingly, different species of this group exhibit bias of different sign between the AOB subdomains (aAOB larger than pAOB or vice versa). Such species-specific biases have been related with contrasting differences in the habitat of the different species (e.g. arid vs. humid environments). Aiming to deepen these observations, we performed a morphometric comparison of the AOB subdomains between two sister species of octodontid rodents, Octodon lunatus and Octodon degus. These species are interesting for comparative purposes, as they inhabit similar landscapes but exhibit contrasting social habits. Previous reports have shown that O. degus, a highly social species, exhibits a greatly asymmetric AOB, in which the aAOB has twice the size of the pAOB and features more and larger glomeruli in its glomerular layer (GL). We found that the same as in O. degus, the far less social O. lunatus also exhibits a bias, albeit less pronounced, to a larger aAOB. In both species, this bias was also evident for the mitral/tufted cells number. But unlike in O. degus, in O. lunatus this bias was not present at the GL. In comparison with O. degus, in O. lunatus the aAOB GL was significantly reduced in volume, while the pAOB GL displayed a similar volume. We conclude that these sister species exhibit a very sharp difference in the anatomical conformation of the AOB, namely, the relative size of the GL of the aAOB subdomain, which is larger in O. degus than in O. lunatus. We discuss these results in the context of the differences in the lifestyle of these species, highlighting the differences in social behaviour as a possible factor driving to distinct AOB morphometries.