Beyond the scalpel

A ten-year-old boy presented with periocular swelling and redness in both eyes since 20 days. There was no history of trauma or fever. His best-corrected visual acuity was 20/20 in the right eye and 20/600 in the left eye. Color vision was reduced in the left eye. External examination revealed bilateral temporal fossa prominence with tenderness and bilateral proptosis with extraocular motility limitation in all gazes. On palpation, bilateral firm superior orbital mass was noted [Fig. 1a]. Slit lamp examination showed bilateral temporal subconjunctival hemorrhage (SCH) with cork-screw conjunctival vessels [Fig. 1b and c]. Fundus examination revealed left eye disc edema [Fig. 1d and e].Figure 1: (a) Clinical photograph showing both eye proptosis with superior orbital mass and temporal prominence. (b) and (c) Slit lamp examination showing both eyes temporal subconjunctival hemorrhage with cork-screw conjunctival vessels. (d) and (e) Fundus photograph of both eyes showing left eye disc edema. (f) and (g) CT orbit coronal cut showing both eyes superior ill-defined, homogenous, isodense lesion, axial cut showing right eye mass extending posteriorly involving the lateral rectus and involvement of the orbital apex in both eyesWhat Is Your Next Step? Incision biopsy of orbit Peripheral blood smear Bone marrow biopsy Incision biopsy of orbit with bone marrow biopsy Findings Computed tomography (CT) orbit showed bilateral superior orbital homogenous masses with involvement of the lacrimal gland on both sides [Fig. 1f and g]. In the right eye, the lesion extended posteriorly, involving the orbital apex, whereas in the left eye, there was soft tissue density at the apex. Peripheral blood smear revealed microcytic hypochromic anemia, thrombocytopenia, and blast cells confirming the diagnosis of acute myeloid leukemia (AML). The child was then referred to a pediatric oncologist and initiated on daunorubicin and cytarabine-based chemotherapy regimen. At 3 years follow-up, the child is in remission with no proptosis and good vision. Diagnosis Bilateral Orbital Myeloid Sarcoma (OMS) Correct Answer: B Discussion Bilateral proptosis in children is uncommon and usually caused by idiopathic nonspecific orbital inflammation, metastatic neuroblastoma, lymphoma, or leukemia.[1] OMS are rare localized tumors of myeloid precursor cells. It may occur concomitantly or progress to AML. It is caused by direct leukemic infiltration or indirect involvement owing to hematological abnormalities. Orbital and optic nerve signs in this case were likely direct whereas conjunctival signs were due to hyperviscosity.[2] Ophthalmic involvement in AML is associated with poor prognosis.[3] OMS should be a major differential in a child with bilateral proptosis, a cork-screw conjunctival vessel with SCH, and a homogenous lesion on imaging. Financial support and sponsorship: Operation Eyesight Universal Institute for Eye Cancer and Hyderabad Eye Research Foundation. The funders have no role in the preparation of the manuscript. Conflicts of interest: There are no conflicts of interest.