Medical Mystery of the Week

      Because of the COVID19 pandemic, you are practicing telemedicine. You interview a 60-year-old asymptomatic man who is concerned about the appearance of his left eye (see pictures below).
      What is your diagnosis, what lab test(s) would you order to confirm you suspicions, and what treatment, if any, do you recommend? 

                                    Eye at rest                                                     Eye with orbital pressure

Because of its excellence, the editor has chosen to post the response of Sarah Anne King, a student at ETSU College of Medicine.
   "Differential Diagnosis:  Conjunctival dermolipoma; lymphoma; epidermoid cyst; subconjunctival fat  prolapse.
   Diagnosis^1,3: Subconjunctival fat prolapse.  Subconjunctival fat prolapse, a benign lesion, results from fat herniating through a weakened Tenon's capsule, a fascial sheath that separates the orbital fat from the globe. The posterior portion of Tenon's capsule separates intraconal fat from the globe and degenerative processes, such as aging, or disruptive processes, such as trauma or surgery, increase the potential for herniation. Although rare, it has been found to be more common in obese, elderly males in the superotemporal quadrant of the eye. 
   This lesion can also be called intraconal fat prolapse or subconjunctival herniation of orbital fat.
   Tests²: As with all eye pathology, it is vital to assess visual acuity and EOMI during the physical exam. Loss of either could potentially be a medical emergency and should be referred to an ophthalmologist immediately. Direct opthalmoscopy and assessment  of visual fields and pupillary integrity should be performed. If not an ophthalmic medical emergency, imaging modalities, such as CT and MRI of the orbits, can help diagnose subconjunctival fat prolapse, which is particularly important in differentiating from potential malignancy.
   Treatment⁴: Subconjunctival fat prolapse has a good prognosis and is usually corrected with transconjunctival excision, a well-known safe and effective surgical procedure. With a rate of recurrence estimated to be approximately 9%, patients can be reassured this lesion is correctable with a low risk of recurrence".
   References:
1. Glover AT, Grove AS Jr. Subconjunctival orbital fat prolapse. Ophthalmic Plast Reconstr Surg. 1987;3(2):83-86. doi:10.1097/00002341-198703020-00005.
2. Kim E, Kim HJ, Kim YD, Woo KI, Lee H, Kim ST. Subconjunctival fat prolapse and dermolipoma of the orbit: differentiation on CT and MRI imaging. AJNR Am J Neuroradiol. 2011;32(3):465-467. doi:10.3174/ajnr.A2313.
3. McNab AA. Subconjunctival fat prolapse. Aust N Z J Ophthalmol. 1999;27(1):33-36. doi:10.1046/j.1440-1606.1999.00159.x.
4. Siban M, Weijtens O, van den Bosch W, Paridaens D. Efficiency of transconjunctival excision of orbital fat prolapse: a long-term follow-up study. Acta Ophthalmol. 2014;92(3):291-293.doi:10.1111/aos.12032.