A 63-year-old white male was referred for evaluation of a lesion and distorted vision in the left eye by his local optometrist. The patient had been detecting wavy lines for some time but was unsure of the duration. He had no significant ocular history. He is currently being treated for arthritis, chronic atrial fibrillation (Afib), hypercholesterolemia, and a skin melanoma that was removed 34 years ago.

His examination revealed 20/20 distant and near visual acuities in each eye, intraocular pressure (IOP) of 13 and 14 in the right (OD) and left (OS) eyes, respectively. His confrontation visual field, pupillary responses, and anterior adnexa were normal. The slit lamp exam revealed mild nuclear sclerosis in both eyes.

Fundus examination was normal in the right eye (Figure 1A). However, in the left eye, a flat partially pigmented “football”-shaped lesion was observed in the temporal macular region (Figure 1B). 

 

The lesion was further investigated through multimodal imaging, including optical coherence tomography (OCT), fundus autofluorescence (FAF), and multispectral imaging (MSI). While the right eye had normal findings (Figure 2), the left eye revealed the following:

Multispectral and FAF imaging of the left eye allowed for a better evaluation of the lesion and its pigmentary changes, and it also facilitated the measurement of the approximately 1.5 mm2 lesion (Figure 3). FAF revealed pigmentary changes trailing the lesion further temporally.

OCT scan of the lesion and its surroundings (Figure 4) showed the lesion at the level of the retinal pigment epithelium (RPE) with partial loss of the RPE and an absence of the outer retinal layers, including the ellipsoid zone (EZ) and the outer nuclear layer (ONL). There was subsidence of the outer plexiform (OPL) and inner nuclear (INL) layers in the area. There was no evidence of a choroidal neovascular membrane (CNVM), subretinal fluid (SRF), or subretinal hemorrhage (SRH).

 

The physical appearance, the presence of pigmentation trailing the lesion as noted on the FAF, and the OCT features make this most likely a case of torpedo maculopathy (TM). The patient was reassured about the benign nature of the lesion. He was educated about the importance of monitoring his vision monocularly and the significance of periodic examinations and surveillance of the lesion. On his most recent follow-up, which occurred 5 years after the initial presentation, his visual acuity remained 20/20, and the lesion remained stable. The patient is being followed by his primary optometrists annually, with our clinic seeing him every 6 months, which is a reasonable follow-up schedule for observing the lesion.

Discussion

Torpedo maculopathy (TM) is a rare congenital lesion referred to by other names, such as solitary hypopigmented nevus of the RPE, paramacular albinotic syndrome, and congenital hypomelanotic freckle. It was first mentioned by Rosen in 1992.1 There are several suggested pathophysiological mechanisms for these lesions, including a developmental defect of the temporal bulge of the RPE during gestation2 or an abnormal development of the choroidal or ciliary vasculature, as more recently shown by multimodal imaging.3

Clinical Findings

Patients presenting with flat, solitary, torpedo-shaped lesions usually have normal vision. There may be the presence of a paracentral scotoma and mild metamorphopsia; however, most of these lesions are discovered as incidental findings.4 These lesions have been subtyped based on their OCT findings into three types, depending on the presence or absence of choroidal cavitation or excavation.5,6 The patient presented here has Type 3, defined by excavation of the inner retinal layers and retinal thinning without a subretinal cleft.5,7 On examination and often in FAF, a small hyperpigmented tail is noted that trails the lesion, as seen in this case.8

The differential diagnosis of TM includes traumatic and nontraumatic chorioretinal scars, congenital hypertrophy of the RPE (CHRPE), hypertrophic lesions associated with Gardner syndrome, simple or combined hamartomas, and neoplastic lesions such as melanoma.9

Associated findings with TM include neurosensory detachment10, central serous chorioretinopathy (CSCR)11. Choroidal neovascular membranes (CNVM) are also associated with TM, and these can be effectively treated with vascular endothelial growth factor inhibitors (anti-VEGF)12. The potential presence of CNVM makes it important that patients presenting with TM receive long-term follow-up12.

Conclusion

Although it is not clear why a patient with a seemingly congenital lesion, in the absence of any secondary complications such as serous detachment or CNVM, suddenly becomes symptomatic, the patient was vigilant and sought proper attention. He was initially seen by an optometrist who subsequently referred him to our clinic for further assessment. Another challenge is presented by the absence of any reference or history regarding the presence of this lesion. Patients may either not seek eyecare often, change practitioners by choice, or face circumstances such as insurance changes. These barriers make it difficult to establish a chronology associated with many ocular or medical conditions.

 

References 

  1. Roseman RL, Gass JD. Solitary hypopigmented nevus of the retinal pigment epithelium in the macula. Arch Ophthalmol. 1992 Oct;110(10):1358-9. doi: 10.1001/archopht.1992.01080220020005. 
  2. Shields CL, Guzman JM, Shapiro MJ, Fogel LE, Shields JA. Torpedo maculopathy at the site of the fetal “bulge”. Arch Ophthalmol. 2010 Apr;128(4):499-501. doi: 10.1001/archophthalmol.2010.29. PMID: 20385950.
  3. Papastefanou VP, Vázquez-Alfageme C, Keane PA, Sagoo MS. MULTIMODALITY IMAGING OF TORPEDO MACULOPATHY WITH SWEPT-SOURCE, EN FACE OPTICAL COHERENCE TOMOGRAPHY AND OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY. Retin Cases Brief Rep. 2018 Spring;12(2):153-157. doi: 10.1097/ICB.0000000000000456. PMID: 27763944.
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  7. Thomas AS, Flaxel CJ, Pennesi ME. Spectral-domain optical coherence tomography and fundus autofluorescence evaluation of torpedo maculopathy. J Pediatr Ophthalmol Strabismus. 2015 Mar 13;52 Online:e8-10. doi: 10.3928/01913913-20150303-01. PMID: 25751084.
  8. Raval V, Rao S, Sudana P, Das T. Torpedo Maculopathy. J Ophthalmic Vis Res. 2020 Feb 2;15(1):113-115. doi: 10.18502/jovr.v15i1.5960. PMID: 32095216; PMCID: PMC7001012.
  9. Golchet PR, Jampol LM, Mathura JR Jr, Daily MJ. Torpedo maculopathy. Br J Ophthalmol. 2010 Mar;94(3):302-6. doi: 10.1136/bjo.2009.162669. Epub 2009 Oct 12. PMID: 19822914.
  10. de Manuel-Triantafilo S, Gili P, Bañuelos Bañuelos J. Torpedo maculopathy: Two case reports and a literature review. Arch Soc Esp Oftalmol. 2016 Aug;91(8):400-3. English, Spanish. doi: 10.1016/j.oftal.2016.01.028. Epub 2016 Feb 28. PMID: 26936143.
  11. Panigrahi PK, Minj A, Satapathy J. Torpedo maculopathy with multifocal central serous chorioretinopathy: A rare case report. Indian J Ophthalmol. 2018 Feb;66(2):330-331. doi: 10.4103/ijo.IJO_812_17. PMID: 29380797; PMCID: PMC5819134.
  12. Shirley K, O’Neill M, Gamble R, Ramsey A, McLoone E. Torpedo maculopathy: disease spectrum and associated choroidal neovascularisation in a paediatric population. Eye (Lond). 2018 Aug;32(8):1315-1320. doi: 10.1038/s41433-018-0074-7. Epub 2018 Mar 20. PMID: 29556011; PMCID: PMC6085330.