Purpose
To report the features of the rare and under-recognized condition of canaliculops (or canaliculocele) of the eyelid, which is a dilation of the canaliculus, and to evaluate treatment with marsupialization.
Design
Retrospective interventional case series.
Methods
The records of 2 patients with canaliculops from the Massachusetts Eye and Ear Infirmary were reviewed. Data collected included clinical history, surgical technique, histopathologic analysis, and comparative immunohistochemical analysis of a range of cytokeratins in normal conjunctival epithelium, normal canalicular epithelium, and canaliculops epithelium.
Results
Two women, 53 and 66 years of age, experienced chronic, noninflammatory, painless medial eyelid and eyelid margin fluctuant swelling after earlier trauma or eyelid surgery. The external mass was accompanied by a whitish opalescent or bluish discoloration of a palpebral surface bulge. Biopsy revealed multilaminar (up to 12 cells thick), nonkeratinizing, tightly packed small squamous epithelial cells that surmounted a highly regimented basal layer with a picket fence arrangement. No goblet cells or subepithelial inflammation were present. Immunohistochemistry revealed only superficial CK7 immunostaining and positive patchy suprabasilar CK17 staining in the canaliculops epithelium, contrasting with their full-thickness positivity and negativity, respectively, in normal conjunctival epithelium. Marsupialization achieved resolution of the condition in each patient.
Conclusions
An improved awareness of the normal canalicular epithelial structure and its immunohistochemical features can definitively separate canaliculops from conjunctival cysts. Previous treatment of canaliculops has involved complete excisions. Canaliculops may, however, be effectively treated with less invasive marsupialization while obtaining an adequate biopsy specimen for histopathologic diagnosis.
Dilation of the lacrimal canaliculus with accumulation of fluid within the lumen is an uncommon event. Distention of the canaliculus (as opposed to pericanalicular inflammatory swelling) is rarely caused by infectious canaliculitis, which is typically accompanied by overt signs of inflammation, suppuration, and the presence of canaliculiths (for example, the “sulfur granules” of actinomyces). Perhaps more frequent is secondary canaliculitis associated with punctal or canalicular plug infection, resulting in pus, mucus, and/or stone formation. Noninflammatory, apparently noninfectious dilation of the canaliculus is extremely rare and idiopathic. An expansion of the canalicular lumen with the accumulation of fluid but not keratin has been described only 3 times previously. One case was probably in error and was more likely a dacryocystocele. The canalicular enlargement has been termed either a canaliculocele or canaliculops. We describe 2 cases of chronic canaliculops in the setting of previous trauma and puncto-canalicular damage. While it took 22 years from the initially acceptable report to the second, our experience is remarkable in that we encountered 2 examples over 3 months. We believe that this condition is likely to be more common but is probably underdiagnosed clinically and frequently misinterpreted histopathologically as a conjunctival cyst.
Methods
This retrospective interventional clinicopathologic study with chart and microscopic slide review was prepared in accordance with the tenets of the Declaration of Helsinki and the Health Insurance Portability and Accountability Act and with the approval of the Institutional Review Board of the Massachusetts Eye and Ear Infirmary, Boston, Massachusetts. The clinical records, operative reports, and preoperative, intraoperative, and postoperative clinical photographs of the 2 cases comprising this study were reviewed. The biopsies were fixed in 10% buffered formalin and analyzed microscopically with the benefit of staining of paraffin-embedded sections with hematoxylin-eosin, periodic acid–Schiff, and Masson trichrome. An incidental portion of normal canaliculus was contained in a medial eyelid excision for another condition and served as a control and the basis of comparison analysis of the ectatic canaliculi. Normal conjunctival epithelium was identified in all 3 specimens and normal epidermis in the control specimen. Their immunohistochemical staining aided in distinguishing differences between conjunctiva and normal and abnormal canalicular epithelia.
Immunohistochemical staining was conducted with monoclonal antibodies reacting against cytokeratins CK7, CK10, CK14, CK17, CK18, CK19, and CK20. All of the immunoperoxidase staining was performed in the Division of Diagnostic Immunohistology of the Department of Pathology at the Massachusetts General Hospital, Boston, Massachusetts. Mouse monoclonal antibodies were employed and were obtained from manufacturers listed in Table 1 . Immunohistochemical staining was performed using the Leica Bond III with appropriate controls to validate antibody quality. The chromogen diaminobenzidine (DAB) was employed for the detection of any immune reaction product and the tissues were counterstained with hematoxylin.
| Probe | Source | Dilution |
|---|---|---|
| Cytokeratin 7 (CK7) | Mouse monoclonal (Dako, Carpinteria, California, USA) | 1:3 |
| Cytokeratin 10 (CK10) | Mouse monoclonal (Dako, Carpinteria, California, USA) | 1:200 |
| Cytokeratin 14 (CK14) | Mouse monoclonal (Leica Biosystems, Newcastle, UK) | 1:100 |
| Cytokeratin 17 (CK17) | Mouse monoclonal (Leica Biosystems, Newcastle, UK) | Prediluted |
| Cytokeratin 18 (CK18) | Mouse monoclonal (Dako, Carpinteria, California, USA) | 1:100 |
| Cytokeratin 19 (CK19) | Mouse monoclonal (Leica Biosystems, Newcastle, UK) | Prediluted |
| Cytokeratin 20 (CK20) | Mouse monoclonal (Leica Biosystems, Newcastle, UK) | Prediluted |
Results
Clinical Findings
Case 1
A 53-year-old African-American woman was referred for evaluation of a chalazion. Swelling of the right upper eyelid began approximately 2 years earlier without resolution and with scant mucoid discharge. She reported no epiphora. Twenty years earlier, during a fight she suffered a right upper eyelid avulsion from a human bite. This was treated surgically without complication. Approximately 15 years ago, she underwent 4-eyelid punctal cautery for dry eyes. Examination revealed an approximately 8 × 8-mm translucent cyst-like structure of the medial right upper eyelid that was centered around the punctal papilla. The punctum was not present, preventing probing and irrigation. The subcutaneous mass was nontender, fluctuant, and transilluminated, and did not express any fluid with compression. Eversion of the eyelid ( Figure 1 , Upper left) allowed the mass to be seen subconjunctivally. Incisional biopsy was performed with a chalazion clamp placed around the lesion ( Figure 1 , Upper right). After eversion of the eyelid, a stab incision was made with an 11 blade through the conjunctival surface. A nonviscous milky liquid emerged from the lumen. A Bowman probe was placed into the hollow cavity and soft stop was encountered at the medial extent of the cystic structure. A window was made through the posterior surface, resulting in marsupialization. The patient healed without reaccumulation of fluid after 9 months of follow-up.
Case 2
A 66-year-old white woman was referred for evaluation of a medial right lower eyelid mass. It was first noted about 2 months earlier and was diagnosed as chalazion, followed by incision and curettage. Several days later, a cystic mass recurred with gradual increase in size. She had a history of punctal cautery of all eyelids followed by punctal plugs of both lower eyelids about 15 years previously. There was no epiphora. Examination revealed 5 × 3.5-mm cystic structure of the right lower eyelid, which was situated beneath the punctum and transilluminated ( Figure 1 , Middle left). The puncta were stenotic. There was no expressible material with firm pressure and probing and irrigation revealed obstruction of the vertical portion of the canaliculi of both lower eyelids. The upper eyelid system was open to irrigation. Incisional biopsy with posterior marsupialization was performed with a chalazion clamp placed around the lesion. A stab incision was made through the conjunctival surface. Clear fluid emerged from the lumen. Passage of a Bowman probe through the lumen resulted in a soft stop at the medial end of the cystic space. Follow-up at 7 months revealed no reaccumulation and identical probing and irrigation findings.
Histopathologic and Immunohistochemical Results
All biopsy specimens evaluated microscopically contained normal conjunctival epithelium, at least a portion of the wall of the canaliculus, and epidermis. The results of immunohistochemical investigations are summarized in Table 2 . A normal canaliculus was fortuitously discovered in a full-thickness lower eyelid resection for another condition and served as a control for comparing results with the canaliculops specimens. The normal canaliculus was composed of nonkeratinizing squamous epithelium without any shed cellular debris in the lumen ( Figure 1 , Middle right). The surrounding connective tissues, including orbicularis striated muscle fibers, were devoid of inflammatory cells. The epithelial lining was distinctive in its composition, with up to 12 cell layers of thickness lacking goblet cells ( Figure 1 , Bottom left). The constituent squamous cells had a moderate amount of eosinophilic cytoplasm and were tightly and compactly arranged with intimate approximation to adjacent cell borders leading to an almost-total obliteration of any identifiable intercellular spaces. The apical epithelium culminated in an adlumenal, flat, vaguely cuticular layer with highly attenuated cytoplasm but apparently viable, elongated, thin nuclei. An arresting characteristic was the highly regimented alignment of side-by-side small basal germinal cells mimicking a picket fence of peripheral palisading ( Figure 1 , Bottom left). The Masson trichrome stain disclosed the circumferential presence of the orbicularis striated muscle fibers, which were more pronounced on the anterior cutaneous aspect of the canaliculus ( Figure 1 , Bottom right); only a few strips of muscle were found beneath the conjunctival epithelium on the posterior aspect ( Figure 1 , Bottom right inset). In comparison, the normal palpebral conjunctival epithelium was more loosely structured, had only 5 or 6 cells of thickness at most, and displayed numerous goblet cells with chronic inflammatory cells in the substantia propria ( Figure 2 , Top left). Immunostaining disclosed that the conjunctival epithelium was CK7, CK14, and CK18 full-thickness positive, and full-thickness negative for CK17 ( Figure 2 , Top right).
| CK7 | CK10 | CK14 | CK17 | CK18 | CK19 | CK20 | |
|---|---|---|---|---|---|---|---|
| Normal epidermis | − | + | + | − | − | − | − |
| Normal palpebral conjunctiva | + | − | + | − | + | + | − |
| Normal canaliculus | − | − | + patchy full thickness | + rare scattered | − | + | − |
| Canaliculops 1 | + superficial | − | + basilar and suprabasilar | + patchy suprabasilar | + superficial | + | − |
| Canaliculops 2 | + superficial | − | + basilar and suprabasilar | + suprabasilar | + superficial | + | − |
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