Ocular manifestation in myeloid/NK cell precursor acute leukemia: a case report. Diagnosed by flow cytometry and PCR from aqueous humor

Abstract

Background: Myeloid/NK cell precursor acute leukemia (MNKL) is a rare type of leukemia, and ocular complications have not previously been reported. We now report a patient with MNKL who developed intraocular infiltrates during follow-up.

Methods and results: A 13-year-old boy diagnosed with MNKL developed left eye pain 3 months after starting treatment. Examination of the left eye revealed a visual acuity of counting fingers at 20 cm, ciliary hyperemia, small corneal keratic precipitates, hypopyon, grade 4 vitreous opacities, and an obscured fundus. The differential diagnosis was between an opportunistic infection associated with immunodeficiency and an intraocular leukemic cell infiltrate. Therefore, a sample of aqueous humor was aspirated. Multiplex PCR/broad-range PCR of the aqueous humor was below detection limits for viruses, bacteria, and fungi. Flow cytometry (FCM) detected NK-related CD56-positive cells, thus leading to a diagnosis of ocular infiltrates due to MNKL. With treatment of the ocular infiltrates by consolidation systemic chemotherapy including intrathecal methotrexate (MTX), there was clearing of the vitreous opacities; and optic disc swelling, retinal hemorrhages, exudates, and protuberant lesions were now seen. With the addition of local radiation therapy to the eye, there was a dramatic treatment response, with regression of the optic disc findings and retinal lesions, and an improved visual acuity of 1.5.

Conclusion: We encountered the first case of MNKL in which ocular infiltrates developed during follow-up. Multiplex PCR and FCM of the aqueous humor were useful in rapidly distinguishing leukemic cell infiltrates from an opportunistic infection. This case highlights the usefulness of intrathecal MTX and local radiotherapy in treating ocular infiltrates in patients with MNKL.

Figure 1

(A) Slit lamp examination at initial evaluation. There was ciliary injection and a hypopyon in the left eye (white arrow). (B) Funduscopy at initial evaluation. The fundus was obscured due to grade 4 vitreous opacities.

Figure 2

Flow cytometry of the aqueous humor. CD56-positive natural killer (NK) cells were detected in the aqueous humor. (A) Gating of infiltrating cells in the aqueous humor. (B) Confirmation of CD56-positive cell infiltrates (upper left panel).

Figure 3

Cranial computed tomography (CT) and magnetic resonance imaging (MRI) findings. No infiltrates of the orbit or optic nerve were present.

Figure 4

(A) Fundus after systemic chemotherapy with intrathecal methotrexate (MTX). Corrected visual acuity was 0.6. Examination of the fundus, which could now be visualized, showed retinal hemorrhages, exudates, protuberant lesions in the retinal periphery (white arrow), and swelling of the optic disc. (B) After radiation therapy (1.5 Gy × 17). Corrected visual acuity was 1.0. At 4 months after starting treatment, the optic disc swelling improved, the protuberant lesions in the retina disappeared, and only a few retinal exudates remained (white arrow).