Tubercular Sclerouveitis Masquerading as an Ocular Tumor: A Case Report

Abstract

Purpose: To report the diagnosis of a case of tubercular sclerouveitis, which masqueraded as an ocular tumor.

Design: Case report.

Methods: Retrospective medical chart review including serological, radiological, and histopathological investigative results.

Results: A patient presented with recurrent episodes of sclerouveitis in his right eye. Serological investigations for infective and connective tissue disorders were negative. Radiological investigation was suggestive of a scleral perforation. The eye was enucleated and histopathological examination showed chronic inflammation. Polymerase chain reaction of the ocular tissue was positive for IS1160 for Mycobacterium tuberculosis.

Conclusion: Infective scleritis should be suspected in cases of scleritis that progress despite treatment. Polymerase chain reaction is instrumental in diagnosing challenging cases.

KEYWORDS::

• Infective scleritis
• Masquerade
• Polymerase chain reaction
• Tuberculosis
• Tubercular sclerouveitis

Tuberculosis and its varied manifestations has often been a subject of interest in an endemic country like India. Despite the years of experience and armamentarium of investigations available, it continues to baffle ophthalmologists. We here report such a case of tubercular sclerouveitis, which masqueraded as an ocular tumor.

CASE REPORT

A 43-year old male who had been diagnosed elsewhere with recurrent sclerouveitis in his right eye presented to us with complaints of pain, redness, photophobia, and swelling in the same eye for a period of 2 months. The symptoms had increased in severity over the past 1 month and were associated with a profound loss of vision.

Our patient stated his symptoms started 2 years back. He was then investigated for Mantoux (13 mm), antinuclear antibody, rheumatoid factor, and syphilis (Venereal Disease Research Laboratory), all of which were unremarkable. He was then submitted to topical and systemic corticosteroids in combination with systemic methotrexate. Since the inflammation was persistent he was switched over to oral cyclophosphamide. During the course of treatment he became a steroid responder, and was started on antiglaucoma medications. One month prior to presentation he gave a history of steroid injection in his right eye. However, when the patient reported to us he had been totally off medications for the past 15 days.

On examination the best-corrected visual acuity in his right eye was hand movements for distance with less than N36 for near. Left eye vision was 6/6 for distance and N6 for near. Right eye slit-lamp biomicroscopic examination revealed lid edema and diffuse scleritis. A whitish, subconjunctival deposit was seen in the inferonasal scleral quadrant, probably a periocular steroid. The cornea showed microcystic edema. Anterior chamber reaction was intense with a fibrin membrane over the pupil, few exudates over the iris, trace hypopyon, and posterior synechiae along with the presence of complicated cataract. Fundus could not be examined due to the hazy media. Left eye anterior and posterior segment examination was within normal limits. Intraocular pressure recorded was 21 and 15 mmHg in the right and left eye, respectively.

An USG-Bscan of the right eye showed few low reflective echoes in the vitreous cavity. An irregular mass lesion was noted within the ocular coats anteriorly involving the superonasal, nasal, and the inferonasal quadrants with widening of the subtenon space (Figure 1). A variable reflective membrane arising from the optic nerve head extending over the suspicious mass lesion with a corrugated appearance and poor after movements was noted, which was suggestive of retinal detachment (Figure 2).

FIGURE 1  USG Bscan of right eye showing an irregular mass lesion within the ocular coats.

FIGURE 2  USG Bscan showing retinal detachment in right eye.

Further investigations were ordered to aid our diagnosis: ANCA, tests for HIV, HbsAg, HCV, and QuantiFERON TB gold test, all of which were negative. Anterior chamber tapping was done and the aqueous aspirate was sent for analysis. In due course the patient was started on topical steroids. With the suspicion of a mass lesion in the globe, magnetic resonance imaging of the brain and the orbit was done, which showed a diffuse enhancing lesion in the nasal quadrant of the right globe with scleral perforation and necrosis and an overlying enhancing lesion (Figures 3 and 4). The results of the aqueous aspirate analyzed by polymerase chain reaction was negative for panfungal genome and Mycobacterium tuberculosis (MPB64 and IS6110) and positive for Eubacterium genome.

FIGURE 3  Axial section MRI showing diffuse enhancing lesion nasal to the right globe.

FIGURE 4  MRI surface coil T2 showing scleral perforation and necrosis and an overlying enhancing lesion in the right globe.

He was started on oral ciprofloxacin at a dose of 500 mg per day. Two days later the eye showed further deterioration and the vision dropped to light perception. The probability of a masquerade was considered because imaging revealed an intraocular mass with an extraocular extension. The right eye was unsalvageable and in an effort to save the other eye, as the right eye mass lesion was very close to the optic nerve head, right eye enucleation was decided upon. Intraoperatively, globe dissection proved to be difficult as the globe was adherent to the recti muscles, more so in the medial and inferonasal quadrants.

The enucleated globe was subjected to histopathgological examination. The gross report showed a normal-sized globe, with thickened choroids nasally, clear vitreous, and detached retina, with a whitish mass in the orbit measuring 14 mm anteroposteriorly, 15 mm transversely, and 15 mm vertically (Figure 5). Microscopic examination revealed dense infiltrates in the ciliary body, choroids with lymphocytes, neutrophils, neutrophilic debris, and fibrocytic proliferation extending onto the sclera. The retina was detached and the subretinal fluid showed inflammatory cells. Dense collection of lymphocytes and plasma cells in the choroids along with intraretinal inflammation was seen. Scleral rupture was noted nasally (Figure 6). Gram stain for bacteria, Gomori methanamine stain for fungus, and acid-fast staining for Mycobacterium were all negative. Polymerase chain reaction of the ocular tissue was performed for Mycobacterium tuberculosis, which turned out to be positive for IS1160 but was negative for MPB64 (Figure 7).

FIGURE 5  Gross specimen of the enucleated eye showing thickened choroids with a whitish mass adherent to the globe nasally.

FIGURE 6  Histopathological specimen suggestive of chronic inflammation.

FIGURE 7  PCR positive for IS6110 of Mycobacterium tuberculosis.

The patient was referred to a pulmonologist to investigate for systemic tuberculosis, which turned out to be noncontributory. The patient was then started on systemic antitubercular therapy and is on a regular follow-up with us.

DISCUSSION

Ocular tuberculosis represents an extrapulmonary dissemination of Mycobacterium tuberculosis primarily from the lung and is relatively less common than pulmonary disease. Establishing a definitive diagnosis is possible in a vast majority of patients with pulmonary tuberculosis based on clinical evidence of exposure to individuals with active systemic tuberculosis, chest radiograph findings, positive TST results, and culture of sputum results or other approaches.^1–3 In patients with ocular tuberculosis, however, chest radiographs can demonstrate negative results, ocular findings often are nonspecific, and patients initially or subsequently may not provide the history of prior exposure to tuberculosis. Unlike pulmonary disease, the diagnosis and treatment of ocular tuberculosis is challenging in the absence of clinically apparent pulmonary disease. The challenge is complicated by difficulties in isolating the organisms from aqueous aspirates, tests that are neither entirely sensitive nor specific, and the variability in clinical presentation.

The diagnosis of ocular tuberculosis is typically made when there is evidence of eye involvement primarily in the form of granulomatous inflammation with demonstration of acid-fast bacilli⁴ under microscope or by culture. In our patient, however, neither the acid-fast bacilli nor Langerhans giant cells could be demonstrated histopathologically. Wrobleski et al. in their recent report have stressed the fact that tuberculous organisms are often difficult to find, require prolonged searches, are associated with giant or epitheloid cells and necrosis, and are generally fewer in number. Caseation necrosis is also rare.⁵

More recently polymerase chain reaction (PCR) analysis has been used in detecting bacterial genomic DNA.⁵ Because biopsy of inflamed ocular tissue is required for histopathologic support of the tuberculosis diagnosis and because of the risks and difficulties in isolating the Mycobacterium from an anterior chamber tap, there is a paucity of such pathologic material to address pathogenesis and the clinicopathologic correlations. In our patient, even though the histopathology was not very conclusive, the nested polymerase chain reaction of the enucleated globe was positive for IS6110, suggesting a tubercular etiology.

Ocular tuberculosis masquerading as ocular tumors has been reported previously, and these referrals revealed prehistopathologic diagnosis of retinoblastoma in 2 patients, squamous cell carcinoma in 1 patient, and juvenile xanthogranuloma in another.⁶ In our case, too, there was a high grade of clinical suspicion regarding the possibility of a masquerade.

Tubercular panophthalmitis is a rare entity; only handful of cases have been reported so far.^7–11 Our patient had been suffering from recurrent sclerouveitis, most probably due to a tubercular etiology. Periocular steroids in a case of scleritis have always been a subject of controversy, even though many reports have found convincing results.¹² The periocular injection administered in our patient in an already compromised sclera could have triggered a massive inflammatory response causing scleral necrosis and thinning and perforation, leading to panophthalmitis, which ultimately led to enucleation.

Tuberculosis has reemerged as the most common cause of mortality from any single infectious disease, with extrapulmonary disease now constituting a greater proportion of all patients with TB, especially in immunocompromised individuals and the elderly.¹³ Because of the lack of diagnostic criteria, it is often difficult to in initiate ATT. The increasing use of PCR for detection of Mycobacterium tuberculosis from the intraocular fluids has contributed to the expanding spectrum with more recently recognized manifestations of disease.¹³ As in our case, polymerase chain reaction proved to be instrumental in establishing the diagnosis.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.