Amelanotic choroidal melanoma presenting as tubercular granuloma

Sashwanthi Mohan; Dilip Mishra; Vishal Raval

doi:10.4103/jocr.jocr_2_22

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CASE REPORT

Year : 2022 | Volume : 2 | Issue : 1 | Page : 47-50

Amelanotic choroidal melanoma presenting as tubercular granuloma

Sashwanthi Mohan¹, Dilip Mishra², Vishal Raval³
¹ Sankara Nethralaya, Retina and Vitreous Services, Chennai, Tamil Nadu, India
² Department of Ophthalmic Pathology Laboratory, L V Prasad Eye Institute, Kar Campus, Hyderabad, Telangana, India
³ Center of SMT.Kanuri Santhamma for Vitreo-Retinal Diseases, L V Prasad Eye Institute; SMT. Kanuri Santhamma Centre for Vitreo-Retinal Diseases, The Operation Eyesight Universal Institute for Eye Cancer, L V Prasad Eye Institute, Hyderabad, Telangana, India

Date of Submission	11-Feb-2022
Date of Decision	22-Mar-2022
Date of Acceptance	23-Mar-2022
Date of Web Publication	05-Oct-2022

Correspondence Address:
Dr. Vishal Raval
The Operation Eyesight Universal Institute for Eye Cancer, L V Prasad Eye Institute, Hyderabad - 500 034, Telangana
India

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jocr.jocr_2_22

Abstract

A 52-year-old woman presented to our outpatient department with chief complaints of progressive diminution of vision in the left eye for 1 year. She did receive antitubercular treatment for 1 year in view of presumed choroidal lesion of tubercular origin. However, the lesion continued to increase in size and hence the patient came for second opinion. Multimodal imaging such as ultrasonography (A and B scan) along with indocyanine green angiography was suspicious for malignant choroidal melanoma. A diagnostic fine-needle aspiration biopsy confirmed the clinical diagnosis of amelanotic variant of choroidal melanoma. The patient subsequently underwent treatment with plaque brachytherapy. At 3-month follow-up, the tumor regressed with reduction in height as well as surrounding retinal pigment epithelial atrophy.

Keywords: Amelanotic choroidal melanoma, brachytherapy, choroidal imaging, choroidal lesion, diagnostic biopsy

How to cite this article:
Mohan S, Mishra D, Raval V. Amelanotic choroidal melanoma presenting as tubercular granuloma. J Ophthalmol Clin Res 2022;2:47-50

How to cite this URL:
Mohan S, Mishra D, Raval V. Amelanotic choroidal melanoma presenting as tubercular granuloma. J Ophthalmol Clin Res [serial online] 2022 [cited 2023 Nov 29];2:47-50. Available from: http://www.jocr.in/text.asp?2022/2/1/47/357890

Introduction

Amelanotic choroidal lesion includes a variety of benign and malignant conditions; thereby seeming to be a diagnostic dilemma to clinicians. We present a case report of amelanotic choroidal melanoma masquerading as infectious etiology. We aim to describe the differential diagnoses of amelanotic choroidal lesions, multimodal imaging features, and role of diagnostic biopsy to confirm the diagnosis.

Case Report

A 52-year-old female presented with complaints of painless gradual diminution of vision in left eye for the past 1 year. She had consulted elsewhere a year ago and was diagnosed to have presumed choroidal lesion of tubercular origin in view of positive Mantoux test (10 mm). She received a course of antitubercular treatment (four-drug regimen) and oral corticosteroids (1 mg/kg) along with immunosuppressant (mycophenolate mofetil 1 g twice a day) in the last 6 months. She had also received three intravitreal anti-vascular endothelial growth factor injections of Ziv-aflibercept. Considering there was no improvement, the patient came to our institute for a second opinion. At presentation, the best-corrected visual acuity was 20/20, N6 in the right eye, and 20/250, N36 in the left eye. Anterior segment of both eyes was within normal limits. Intraocular pressure in both eyes was 15 mm of Hg. Right eye fundus examination was unremarkable. Fundus examination of the left eye showed an elevated hypopigmented choroidal lesion measuring 5.5 mm × 4.5 mm × 3.4 mm in the superotemporal quadrant area with surrounding subretinal fluid [Figure 1]a. There was absence of surface orange pigment, drusens, or retinal pigment epithelial atrophy. Considering the poor response to oral antitubercular treatment and corticosteroids, a strong suspicion for amelanotic variant of choroidal melanoma was contemplated.

Figure 1: A 52-year-old woman presented to our clinic for left eye suspicious choroidal lesion. (a) The color fundus photograph of the left eye showed an amelanotic choroidal lesion measuring 5.5 mm × 4.5 mm × 3.4 mm in the superotemporal arcade area with surrounding subretinal fluid. (b) Ultrasonography B-scan of the left eye demonstrated a smooth dome-shaped homogenous choroidal lesion with high surface and low internal reflectivity on A-scan. (c) Optical coherence tomography showed an elevated choroidal lesion with compression of overlying choriocapillaris with the presence of shaggy photoreceptor layer and subretinal fluid. (d and e) Indocyanine green angiography showed hypofluorescence of the lesion in both early and late phases. (f) The color fundus photograph at 3-month follow-up showed tumor atrophic changes with resolution of subretinal fluid. (g) Ultrasonography B-scan showed reduction in tumor thickness when compared from first visit

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Ultrasonography (B scan) showed a smooth, dome-shaped homogenous, elevated choroidal lesion with surrounding exudative retinal detachment involving the posterior pole. The corresponding A-scan demonstrated increase surface reflectivity with low internal reflectivity [Figure 1]b. Optical coherence tomography (OCT) through the lesion showed an elevated choroidal lesion with compression of the overlying choriocapillaris and irregular outer retinal layers [Figure 1]c. There was the presence of exudative fluid over the lesion and in the foveal area. Indocyanine green angiography (ICG) demonstrated hypofluorescence of the lesion in the early as well as the late phase of the angiography [Figure 1]d and [Figure 1]e. Blood investigations performed to rule out systemic tuberculosis, and other inflammatory diseases were negative. In view of poor response to treatment and characteristic multimodal imaging features, a strong clinical suspicion of amelanotic choroidal melanoma was kept in mind. The patient was counseled for a diagnostic fine-needle aspiration biopsy which was undertaken using a transvitreal approach. Two ports 23-gauge valve trocars were used with noncontact retina viewing system. A long 24-gauge needle connected to a 2-ml syringe was gently inserted into tumor apex avoiding major retinal blood vessels with gentle suction applied to obtain the biopsy specimen. After removing the needle, 0.5 ml of saline was injected to increase intraocular pressure and prevent biopsy-related vitreous hemorrhage.

Histopathological examination of the cellular aspirate showed loose cluster of spindle cells with vesicular nuclei and conspicuous nucleoli [Figure 2]a. Immunostaining with two special melanocytic markers showed strong expression for Melan-A and HMB-45 thereby confirming the final diagnosis of medium size, amelanotic choroidal melanoma [Figure 2]b and [Figure 1]c. The patient was referred to medical oncologist to screen for any distant metastasis. The whole-body positron emission tomography and computed tomography scan was negative for any metastasis lesion.

Figure 2: (a) Photomicrograph of diagnostic biopsy showed moderate cellularity with loose clusters of spindle cells with vesicular nuclei and conspicuous nucleoli, admixed with few polygonal and pigmented cells (H and E stain, ×40). (b and c) Analysis by immunohistochemistry using special staining for melanocytic markers showed strong expression for Melan-A and HMB-45 in the lesional cells (×40)

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After thorough counseling and explaining the patient about the nature of the lesion, the tumor was subsequently treated with a 16-mm round ruthenium-106 radioactive plaque delivering a tumor apex (4.5-mm height) radiation dose of 10,000 cGy over treatment time of 76.42 h. Postoperative day 1, a streak of vitreous hemorrhage was seen over the biopsy site. At 3-month follow-up, the BCVA in the left eye remained stable. The tumor showed signs of regression with surrounding RPE atrophic changes and resolution of subretinal fluid [Figure 1]f. The corresponding B-scan showed reduction in height of lesion (3.4 mm to 2.8 mm) [Figure 1]g. The patient was asked to follow up after 3 months.

Discussion

Our patient represented a case of amelanotic choroidal melanoma which masqueraded at initial presentation as tubercular origin choroidal granuloma. However, due to lack of response to antitubercular treatment and corticosteroids, combined with the characteristic multimodal imaging features a diagnosis of amelanotic variant of choroidal melanoma was suspected, which was confirmed by diagnostic fine-needle aspiration biopsy.

Choroidal melanomas are usually pigmented, and amelanotic melanomas are rare making the diagnosis of amelanotic melanomas difficult as they come under the umbrella of a vast number of amelanotic choroidal lesions. Amelanotic choroidal lesions can be both malignant and benign. Differential diagnoses include amelanotic melanoma, choroidal nevus, metastasis, hemangioma, granuloma, osteoma, lymphoma, sclerochoroidal calcification, peripheral exudative hemorrhagic chorioretinopathy, and sclerochoroidal calcification.^[1] Considering, the majority of these lesions have simulating clinical presentation, it is often difficult to differentiate based upon clinical examination. The majority of choroidal melanomas are pigmented, but they can also present as nonpigmented or a combination of pigmented and nonpigmented.^[2]

Berkowitz et al. described a patient with amelanotic choroidal melanoma which was initially misdiagnosed as choroidal granuloma in view of underlying systemic diagnosis of sarcoidosis. Due to the prior history of sarcoidosis, the patient was initially started on oral corticosteroids. However, over the next 1 month, there was increase in subretinal fluid suggesting lack of response to treatment. The patient underwent chorioretinal biopsy with partial resection of the tumor down to bare sclera and cytopathology revealed atypical spindle cells suggestive of melanoma. The preexisting history of sarcoidosis made the diagnosis of amelanotic melanoma difficult but the nonresponse to treatment alerted the clinician to change the diagnosis which was confirmed by biopsy findings.^[1]

Amelanotic melanomas are unilateral, solitary lesions with subretinal fluid, large basal diameter, and characteristic ultrasound appearance. Choroidal tuberculoma is also usually unilateral, solitary, or multiple amelanotic lesions in the posterior pole of the retina. They can occur with or without active tuberculosis.^[3] Clinically, both these lesions are indistinguishable and hence a delay in the diagnosis of choroidal melanoma. Multimodal imaging with OCT, ultrasound B scan, ICG angiography, as well as systemic investigations can help to arrive to the diagnosis in confusing cases. Invasive tests such as ICG angiography in patients with partial-thickness tubercular granulomas demonstrate the mass effect. These are seen as regular-shaped, hypofluorescent lesions in the initial frames that become isofluorescent in the late frames. Similarly, full-thickness granulomas are regular-shaped hypofluorescent lesions that remain hypofluorescent even in the late frames.^[4] ICG angiography findings in case of choroidal granuloma can simulate uveal melanomas and choroidal metastasis by demonstrating hypofluorescence in the early phase that persists through the middle and late phases of angiography. However, there is no vascular supply as observed in cases with large uveal melanomas or rarely metastasis.^[5] Ultrasonography of choroidal melanoma demonstrates a characteristic smooth, dome-shaped, and homogenous lesion with low internal reflectivity. On comparison, tuberculomas will show diffuse, mild elevation in the posterior pole, with moderate-to-high internal reflectivity, and dramatic regression on treatment with corticosteroids which is not a feature of melanomas.^[6],[7]> An initial systemic uveitis workup is warranted in all the cases, particularly in an endemic country such as India, where infectious choroidal granuloma secondary to tubercular or sarcoid origin is the presenting feature. Uveitis work includes Mantoux test, QuantiFERON-TB Gold, serum angiotensin-converting enzyme, lysozyme, erythrocyte sedimentation rate, C-reactive protein, tests for syphilis, and computed tomography of the chest. If infection is ruled out, a trial of corticosteroids showing reduction in size of the mass and resolution of subretinal fluid can point to the diagnosis of inflammatory origin granuloma. Fine-needle aspiration biopsy is rarely indicated when the clinical diagnosis is not clear and there is no response to treatment.^[8],[9]> In our case, diagnostic biopsy was performed as the patient insisted on histopathological confirmation of the disease before contemplating for radiation treatment.

Conclusion

It is important to have a high index of suspicion for amelanotic choroidal tumors, particularly in Asian countries, where infectious origin choroidal granulomas can masquerade and delay the final diagnosis. Clinical findings in combination with ancillary multimodal imaging as well as poor response to treatment should help raise suspicion for underlying malignant lesions.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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