Woman presents with amelanotic deep mass in left eye
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A 79-year-old woman presented for a routine follow-up appointment as a glaucoma suspect in February 2022 at Lahey Medical Center. She reported long-standing difficulty with distance vision in both eyes but had no acute visual complaints.
She was followed as a glaucoma suspect based on cup-to-disc ratio asymmetry and had a history of anatomic narrow angles in both eyes status post laser peripheral iridotomies in 2007 as well as cataracts. She was last seen in 2019 and lost to follow-up since then due to the COVID-19 pandemic.
Source: Omar Abu-Qamar, MD, MMSc, and Kendra Klein-Mascia, MD
Her medical history included hyperlipidemia, osteoporosis, hearing loss and a right middle cerebral artery aneurysm measuring 3 mm × 5 mm, for which neurosurgery recommended intervention but she declined. Her medications included atorvastatin, alendronate, and vitamins D and B12. She was a lifelong nonsmoker and denied alcohol or illicit drug use. She was born in India where she worked as a nurse before immigrating to the U.S. in the 1970s.
Examination
Best corrected visual acuity was 20/40 in the right eye and 20/60 in the left eye. The pupils were equal, round and briskly reactive to light without a relative afferent pupillary defect. IOP, extraocular motility and visual fields by confrontation were all within normal limits. Anterior segment exam was notable for 3+ nuclear sclerotic cataracts and patent peripheral iridotomies in both eyes. In the posterior segment, the cup-to-disc ratio was greater in the right eye. There was a raised amelanotic deep mass in the inferior macula of the left eye (Figure 1). The lesion extended from the subfoveal area superiorly to the inferior arcade inferiorly. Of note, this lesion was not present on her last dilated fundus exam in 2019.
Further imaging
OCT of the left eye centered on the lesion showed trace subretinal fluid, thickening of the photoreceptor outer segments and attenuation of the outer retinal bands. The thickness of the lesion was approximately equivalent to the thickness of the overlying retina (Figure 2).
An ultrasound B-scan of the left eye was obtained but failed to detect the lesion given its small thickness. Notably, the choroid appeared homogenous and isoechoic with no lesions causing shadowing or echo signal blockage (Figure 3).
Fluorescein angiography of the left eye showed early punctate hypofluorescence in the area corresponding to the choroidal lesion and slow leakage in the late phase (Figure 4).
What is your diagnosis?
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Amelanotic choroidal mass
The differential diagnosis for this incidental exam finding of a solitary amelanotic choroidal mass in a 79-year-old woman is wide and includes neoplastic lesions including amelanotic choroidal nevus, amelanotic choroidal melanoma, choroidal metastasis, choroidal lymphoma, choroidal osteoma and choroidal hemangioma (the circumscribed subtype). It also includes granulomatous lesions such as sarcoidosis and tuberculosis.
A more thorough history taking and review of systems were largely unrevealing. Specifically, the patient denied personal or family history of malignancy, B symptoms (fever, night sweats, unintentional weight loss, unexplained fatigue), cough or hemoptysis. She endorsed receiving the BCG vaccine in India, and although she worked as a nurse before immigrating to the U.S., she denied known TB exposure. This necessitated a thorough neoplastic and infectious workup in conjunction with the patient’s primary care physician. While diagnostic testing for malignancy including mammogram, colonoscopy, and chest and abdominal CT scans were negative for malignancy, a PET scan showed calcified, metabolically active mediastinal lymph nodes and hilar lymphadenopathy (Figure 5). Furthermore, her blood workup was positive for QuantiFERON-TB Gold test. Complete blood count, complete metabolic panel, angiotensin-converting enzyme and lysozyme levels were all within normal limits. Therefore, the patient was diagnosed with presumed ocular mycobacteria tuberculosis.
Discussion
When approaching an amelanotic choroidal mass, neoplastic lesions are of specific concern. While distinguishing benign from malignant lesions may not be clear clinically, clinical features and ancillary studies, especially ultrasonography, can help distinguish the diagnosis. Choroidal metastases appear clinically as multiple bilateral lesions with subretinal fluid and are hyperechoic on ultrasound. Amelanotic melanoma presents clinically as a mushroom-shaped lesion with orange pigment and subretinal fluid, and on ultrasound, it demonstrates low reflectivity. This is in contrast to amelanotic nevus, which is typically flat or slightly elevated, associated with drusen but not subretinal fluid, and shows high-medium reflectivity on ultrasound. Choroidal osteoma presents as a whitish-yellow lesion with distinct and scalloped borders. It shows high reflectivity on ultrasound with orbital shadowing due to calcification.
The workup for this patient was significant for metabolically active hilar lymphadenopathy and positive QuantiFERON-TB Gold, and after excluding other diagnoses and considering her background, the patient was diagnosed with ocular TB. As in this case, the diagnosis of ocular TB is often presumptive and one of exclusion because the identification of mycobacteria in ocular tissue or aqueous humor is not always possible. Additionally, ocular TB is a great masquerader with a wide spectrum of signs and symptoms on presentation, which adds to the challenging nature of making such a diagnosis. A useful way to classify ocular TB is the mode of ocular involvement, which includes direct or primary ocular TB infection in which the eye is the entry point of the mycobacterium and often has a predilection for the eyelids (lupus vulgaris), conjunctiva, cornea and sclera; hematogenous spread, which is the most common mode typically from a pulmonary focus and preferentially targets any part of the uvea manifesting as uveitis, choroidal tubercles and serpiginous-like lesions, among others; and finally, hypersensitivity reaction to TB antigen, which manifests as phlyctenular keratoconjunctivitis and Eales’ disease. Once the diagnosis is made (or presumed), ocular TB is treated in the same fashion as pulmonary TB with four-drug RIPE therapy (ie, rifampin, isoniazid, pyrazinamide and ethambutol) for up to 2 months followed by two-drug therapy (rifampin and isoniazid) for up to 4 months.
Our patient was referred to an infectious disease specialist for further management. They agreed that the workup was concerning for TB reactivation, but they recommended against empiric treatment without microbiological or histopathological evidence given risks associated with anti-TB therapy. The patient was then seen in the pulmonary clinic, but she declined endobronchial ultrasound-guided biopsy of the hilar lymph nodes, and an induced sputum smear was not successful. During this period of evaluation, the patient continued to follow at the retina clinic, and interestingly, the lesion demonstrated spontaneous resolution over time (Figure 6). The patient is being monitored for now.
- References:
- Basic and Clinical Science Course. Uveitis and ocular inflammation, section 9. American Academy of Ophthalmology.
- Elkington P, et al. Trends Mol Med. 2022;doi:10.1016/j.molmed.2021.11.004.
- Mir TA, et al. Assessment of amelanotic choroidal mass. In: Medina, CA, et al, eds. Manual of Retinal Diseases: A Guide to Diagnosis and Management. Springer; 2016:185-190.
- Ophthalmologic findings related to tuberculosis. https://eyewiki.aao.org/Ophthalmologic_Findings_Related_to_Tuberculosis. Updated Oct. 4, 2022.
- For more information:
- Edited by Yi Ling Dai, MD, and Teresa P. Horan, MD, of New England Eye Center, Tufts University School of Medicine. They can be reached at ydai@tuftsmedicalcenter.org and thoran@tuftsmedicalcenter.org.