CASE 17591 Published on 17.01.2022

Tuberculosis of the lacrimal sac: A common disease in an uncommon location

Section

Head & neck imaging

Case Type

Clinical Cases

Authors

Sofia Frade Santos, Alexandra Borges

Instituto Português de Oncologia de Lisboa Francisco Gentil, Radiology Department, Lisboa, Portugal

Patient

60 years, female

Categories
Area of Interest Head and neck, Thorax ; Imaging Technique CT, Digital radiography
Clinical History

A 60-year-old woman presented with recurrent episodes of blepharitis and a painless hard lump in the medial canthus. There was no clinical improvement after treatment with several antibiotics and steroids. Fine-needle aspiration cytology revealed a granulocytic exudate. Ziehl-Neelsen stain was negative but cultures were positive for Mycobacterium tuberculosis.

Imaging Findings

An orbital CT scan showed a 2 cm soft-tissue mass in the inferomedial aspect of the right orbit, in a preseptal location, corresponding to the location of the lacrimal sac (figure 1a-d), accompanied by a diffuse thickening of the lower lid and minor dilation of the nasolacrimal duct (figure 1d), compared to the contralateral side. There was also faint stranding of the adjacent extraconal fat. The mass was isodense to muscle and relatively homogeneous on this non-enhanced CT scan. No changes were seen in the adjacent bone and there was no periosteal reaction. The nose and paranasal sinuses were normally aerated with no blockage of the inferior meatus. No enlarged lymph nodes were depicted.

Chest radiograph (figure 2) showed no relevant findings, particularly there were no signs of active pulmonary tuberculosis.

Discussion

Background

Primary tuberculous dacryocystitis is a rare form of oculo-adnexal TB [1,2].

Tuberculosis of the lacrimal apparatus may be primary or secondary to haematogenous spread, direct spread from the sinonasal or orbital region or still by a hypersensitivity response. Therefore, exclusion of systemic TB, particularly pulmonary, is mandatory [1,3].

Tuberculous dacryocystitis presents as a non-tender or mildly painful medial canthus swelling and epiphora[1]. This clinical presentation is unspecific, shared by other infectious, inflammatory and neoplastic causes of nasolacrimal obstruction[3]. Diagnostic hints include an insidious onset, longstanding symptoms refractory to conventional treatment, previous history of TB or contact with a TB patient and the presence of fistulous/sinus tracts[1].

Diagnosis requires a high degree of suspicion.  Cultures remain the gold-standard for diagnosis but their sensitivity in this extrapulmonary location is compromised by the paucibacillary nature of the disease [1,2]. Acid-fast bacilli staining (Ziehl–Neelsen), Mantoux and/or IGRA (interferon-gamma release assay) test and PCR (polymerase chain reaction) also have variable sensitivities. Histopathology typically shows a chronic granulomatous inflammation with caseating necrosis. In difficult cases, diagnosis can be corroborated by a favourable response to antibacillary agents [2-4].

Treatment of tuberculous dacryocystitis is with a 6-18 months course of anti-tubercular therapy [4-7].

Imaging Perspective

Cross-sectional imaging is mandatory to assess the exact location and extent of the disease and to differentiate the 5 different forms of orbito-adnexal TB: classical periostitis, orbital soft tissue tuberculoma without bone destruction, orbital TB with bone involvement, orbital spread from the paranasal sinuses and TB of the lacrimal apparatus [4, 8-10]. Imaging is crucial to depict disease extent. Intravenous contrast should be given to highlight the inflammatory changes, depict abscess formation and fistulous tracts [9]. Chest radiograph or CT of the chest is mandatory to rule out signs of pulmonary TB [1].

Outcome

Anti-bacillary treatment was initiated, including four antibiotics (isoniazid, rifampicin, pyrazinamide, and ethambutol) for the initial phase followed by isoniazid plus rifampicin for the maintenance phase. There was a good clinical and radiological response to treatment (figure 3).

Take-Home Message

  • Primary TB of the lacrimal sac can be a challenging diagnosis as it is a very rare form of TB;  a high degree of clinical suspicion is required. Associated sites of TB should be sought.
  • Although culture is the gold standard for the diagnosis of tubercular dacryocystitis, when negative it does not rule out the diagnosis.  

Written informed patient consent for publication has been obtained.

Differential Diagnosis List
Tuberculous dacryocystitis
Lacrimal sac mucocele
Nasolacrimal carcinoma
Lymphoma
Infection / inflammation
Foreign body
Final Diagnosis
Tuberculous dacryocystitis
Case information
URL: https://www.eurorad.org/case/17591
DOI: 10.35100/eurorad/case.17591
ISSN: 1563-4086
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