OBJECTIVE: Our aim was to evaluate a potential role for the lacrimal drainage system (LDS) as a portal of entry and conduit for SARS-CoV-2 in human infection. We also investigate the mucosal surface area. The relatively long tear contact time in a closed system raises the possibility that this pathway may contribute to the initiation of systemic infection. We looked for expression of ACE2, the main receptor for SARS-CoV-2, as well as cofactors such as TMPRSS2 and other enzymes such as cathepsinB, CD147, elastase1, furin, neuropilin1, neuropilin2, TMPRSS11D and trypsin which also play a role in SARS-CoV-2 infection, in this system.
METHODS: Human tissue samples of the draining tear ducts from body donors were analyzed by RT-PCR, Western blot and immunohistochemistry. It is not known whether the respective body donors were Sars-Cov-2 positive at any time; they were negative when they entered the institute. Besides, the draining LDS of body donors were measured to determine the mucosal surface in the lacrimal system.
RESULTS: The expression of the main receptor studied, ACE2, cofactors such as TMPRSS2 and other enzymes such as cathepsinB, CD147, elastase1, furin, neuropilin1, neuropilin2, TMPRSS11D and trypsin were all detected at the gene and protein level. The average mucosal surface area of the lacrimal sac and nasolacrimal duct was calculated to be 110 mm2.
CONCLUSIONS: The results show the presence of all analyzed receptors in the efferent LDS. With an average tear passage time of 3 min and a relatively large mucosal surface area, the LDS could therefore be considered as a portal of entry and conduit for SARS-CoV-2. In addition, it represents a surface that should be taken into consideration in the administration of topically applied medication to the ocular surface.

UNASSIGNED: To report a rare case of a pediatric dacryolith masquerading as congenital nasolacrimal duct obstruction (CNLDO).
UNASSIGNED: A two-year-old male child presented with history of intermittent epiphora and discharge since the age of six months. Clinical evaluation demonstrated raised tear meniscus height and delayed fluorescein dye disappearance test in the right eye. Lacrimal irrigation of the right eye under general anesthesia demonstrated 90 % regurgitation (subjectively) of mucoid fluid with a hard stop. Nasal endoscopy examination demonstrated a dacryolith obstructing the opening of the nasolacrimal duct (NLD) in the inferior meatus. The dacryolith was teased out of the NLD and following its removal the lacrimal irrigation was freely patent. At six-months post operative follow up, epiphora resolved and the child was asymptomatic.
UNASSIGNED: While cases of canaliculitis is uncommon in pediatric age group, it is rare to find a NLD dacryolith in a toddler. To the best of the authors\' knowledge, there are few prior reports on pediatric NLD dacryolith masquerading as CNLDO in a toddler (1-3 years).

UNASSIGNED: An understanding of the anatomical structure is crucial for completing successful endoscopic dacryocystorhinostomy (DCR) surgery. This study aimed to precisely delineate the spatial relationship between the lacrimal sac and the agger nasi cell (ANC) and evaluate the impact of ANC on surgical strategies in endoscopic DCR.
UNASSIGNED: This retrospective cross-sectional study included 110 Han Chinese patients diagnosed with unilateral primary acquired nasolacrimal duct obstruction (PANDO) from January 2021 to June 2023. This study was conducted in Eye, Ear, Nose, and Throat Hospital of Fudan University and involved inpatient participants who were scheduled for DCR surgery under general anesthesia. Patients were consecutively enrolled. The patients underwent preoperative computed tomography-dacryocystography (CT-DCG), and contrast-enhanced images were used to locate the positions of the lacrimal sac and the common canaliculus. A dynamic approach was adopted to analyze the multiplanar CT imaging, facilitating a detailed assessment of the morphology of the lacrimal drainage system and potential overlap of the lacrimal sac. Patient ages and measured values are presented as the mean ± standard deviation, which were measured three times by the same observer and averaged for statistical analysis.
UNASSIGNED: The prevalence of ANC in this study was 90.9% (100/110). Dynamic examination revealed that only 42.7% (47/110) of ANCs appeared as discrete cells, while the majority were connected to nearby sinus openings. Spatial analysis showed that in 57 out of 110 cases, ANCs were situated below the common canaliculus and not posterior to the lacrimal sac, indicating an overlap rate of 51.8%. Notably, our dynamic approach identified five critical cases of overlap below the level of the common canaliculus, which might have been missed by prior studies that used different methodologies.
UNASSIGNED: More than half of the ANCs exhibited overlap with the lacrimal sac, suggesting a significant proportion may necessitate opening during endoscopic DCR procedures. ANCs are often interconnected with adjacent nasal sinuses, necessitating careful consideration in the decision to open the ANCs during surgery. The dynamic evaluation employed in CT-DCG effectively assessed the extent of ANC coverage over the lacrimal sac.

Lacrimal sac tumors are rare with epithelial tumors being the most common type. Melanoma of the lacrimal sac is an exceptional finding. Few cases have been reported so far in the literature. We report the case of a sixth year old male, with no pathological background, who was referred to the hospital for chronic dacryocystitis resistant to treatment. Computed tomography dacryocystography and magnetic resonance imaging were performed, in favor of a large mass of the lacrimal sac and lacrimal canal suggestive of melanoma. Biopsy confirmed the diagnosis. PET-CT was positive and showed abnormal activity in the lung, liver and bones, in favor of metastasis.

Non-Hodgkin\'s lymphoma (NHL) of the lacrimal sac is a rare, yet clinically significant entity within the spectrum of ocular malignancies. While primary lacrimal sac lymphoma is uncommon, it poses unique diagnostic and therapeutic challenges due to its anatomical location and potential for aggressive behavior. Despite advancements being made in the current understanding and treatment of NHL, research that specifically addresses the involvement of the lacrimal sac is currently lacking. Thus, the present review aimed to provide insight into the epidemiology, clinical presentation, diagnostic modalities, histopathological features, treatment strategies and prognosis of lacrimal sac NHL. Through a methodical analysis of previous literature, the present review highlights the diverse spectrum of NHL subtypes that affect the lacrimal sac, including diffuse large B-cell lymphoma, extranodal marginal zone lymphoma, mantle cell lymphoma and follicular lymphoma. Moreover, the present review discusses the role of advanced imaging techniques in accurate staging and treatment planning, including computed tomography (CT), magnetic resonance imaging and positron emission tomography-CT. The present review also discusses evolving treatment approaches, such as surgical intervention, chemotherapy, radiotherapy, immunotherapy, combinations of the aforementioned treatments and targeted therapy. In addition, the present review highlights the significance of multidisciplinary collaboration in attaining optimal outcomes for individuals with lacrimal sac NHL. The present review aimed to provide a basis for \'further investigations into novel treatment modalities and prognostic markers that may aid in guiding personalized management strategies, ultimately improving outcomes for patients with NHL.

Langerhans cell histiocytosis (LCH) is a myeloid neoplasm characterized by clonal neoplastic proliferation of Langerhans-type dendritic cells associated with an inflammatory infiltrate predominantly composed of lymphocytes and eosinophils. In this article, we present an unusual case of LCH with significant swelling in the left lacrimal sac region in a 3-year-old child, clinically mimicking acute dacryocystitis. Microscopically, it showed intense inflammatory infiltrate and histiocytes with irregular nuclei. The tumor cells were positive for S-100 protein, CD1a, and CD207 (langerin). Molecular study was positive for the V600E/E2/D mutation (EXON 15). This case emphasizes the importance of careful clinical, radiographic, and microscopic evaluation, as some neoplasms may mimic common benign lesions.

UNASSIGNED: To evaluate the clinical usefulness of digital radiography dacryocystography in patients with primary acquired nasolacrimal duct obstruction prior to endoscopic dacryocystorhinostomy.
UNASSIGNED: All dacryocystography images from 129 patients with primary acquired nasolacrimal duct obstruction were analyzed. Each group was assessed for postoperative epiphora severity using Munk\'s score via telephone follow-up three years post-surgery. Receiver operating characteristic (ROC) curve was plotted to obtain a suitable cutoff value of the transverse diameter of the lacrimal sac (LS), used to categorize LS size into small (≤4.350 mm) and large (>4.350 mm).
UNASSIGNED: Analysis of the transverse diameter of the LS among 129 patients showed a negative correlation between it and Munk\'s score (r = -0.282, p = 0.001). There was a statistical difference between the surgical outcomes and the sizes of the LS (p = 0.041). The ROC curve analysis showed that the transverse diameter of the LS at 4.350 mm was the ideal cutoff value for the outcome of endoscopic dacryocystorhinostomy, with a sensitivity of 42.2 %, and specificity of 92.3 %. After adjusting for the age and sex, the small LS was associated with an increased risk of postoperative failed outcome (adjusted odds ratio [95 % CI]: 8.628 [1.074, 69.335]).
UNASSIGNED: The small LS was independently associated with the failed surgical outcome. Furthermore, the preoperative measurement of the LS transverse diameter serves as one of the reliable predictors for postoperative epiphora severity.

Amyloidosis involving the lacrimal sac is extremely rare. In this study, we demonstrated a rare case of localized light chain amyloidosis in the lacrimal sac region. The lacrimal sac lesion presented as infiltrative with bony erosion. Given the slow growth of the lesion and the absence of a blood flow signal inside, we concluded that the lesion was less likely to be malignant. Complete removal of the lacrimal sac lesion combined with simultaneous lacrimal passage reconstruction was performed. The diagnosis of light chain amyloidosis was confirmed by histology. The surgical results were favorable, and no recurrence was observed over one-year follow-up. Our case report enriches the understanding of amyloid deposition in the ocular adnexa.

OBJECTIVE: To study the structural and dynamic alterations in the lacrimal sac vasculature of patients with congenital, primary, and secondary acquired nasolacrimal duct obstructions (CNLDO, PANDO, SANDO) and patients with acute dacryocystitis (AD) and failed dacryocystorhinostomy (DCR).
METHODS: A prospective study was performed on 65 consecutive lacrimal sacs following their complete exposure during endoscopic dacryocystorhinostomy. High magnification chromo endoscopy and changes in effective spectral response was achieved using the Storz professional image enhancement system (SPIES®). Structural characteristics studied include vascular arrangement, superficial and deep vessels, vessel calibers on cut section, abnormal branching, localized and generalized dilatations and pathologies like varices. Flow characteristics in different caliber vessels and their alterations were assessed in Spectra A mode of SPIES®.
RESULTS: Distinct vascular alterations were noted in several lacrimal disorders. Vascular dilatations differed between the fundus and the body segments of the lacrimal sac, except in cases of traumatic SANDO and prior failed DCRs. 23% (7/30) of PANDO sacs showed peri sac varices and severe tortuosity. The flow in the dilated vessels was either very slow or showed intermittent backflow. Moderate dilatation of peri sac venous plexus with distinct surface linear vessels was noted in CNLDO. The cut surface of the sac wall and luminal surface differentially demonstrated several vascular patterns like speckled, scattered, branched loops, and skip areas in various diseased states.
CONCLUSIONS: The present study found distinct alterations of lacrimal sac vasculature in several lacrimal drainage disorders and provides impetus to the vascular theory for pathogenesis of PANDO.

OBJECTIVE: The purpose of this study is to describe a simplified, less invasive dacryocystotomy technique that allows for complete inspection of the canine lacrimal sac and to retrospectively evaluate this surgical technique in a larger series of dogs. The anatomical background of the canine nasolacrimal system is described as a basis for the surgical technique.
METHODS: Records of dogs from 2003 to 2023 which were diagnosed with dacryocystitis due to presumed foreign body and underwent surgical exploration and removal of foreign bodies within the lacrimal sac using this technique were reviewed. Postoperative treatment and outcome were evaluated.
RESULTS: Records of 48 dogs were included. A foreign body was discovered during the surgery or upon retrieval of the catheter in 85% of cases (41/48). An indwelling catheter was placed in 83% of cases (40/48) for a median of 21 days. At the last recheck, the nasolacrimal duct was patent in 87% of the cases (41/47). The median follow-up time was 34 days (3-1255 days). The most commonly affected breeds were Golden retrievers (11) and dachshunds (8). The following complications occurred: two dogs removed or partly removed the catheter themselves (day 7, day 14), and one dog showed marked irritation at the catheter site which had to be removed by day 10.
CONCLUSIONS: The transconjunctival dacryocystotomy technique is simple and less invasive than other described techniques with a successful long-term outcome in the majority of cases.