CHAPTER 5Abnormalities of the Iris, Ciliary Body, and Angle StructuresIn this chapter, lesions of the iris, ciliary body, and anterior chamber angle that are important in ocular cytology are illustrated. There are only a few lesions of the ciliary body, iris, and angle that are frequently ecountered in cytologic specimens. Infectious processes of the anterior chamber, iris, and ciliary body are presented in Chapter 8. Leukemias may involve the iris and shed cells into the aqueous, but are presented with other malignant neoplasms in Chapter 9. Choroidal melanomas are illustrated here.
HEMOGLOBIN SHERULOSIS AND GHOST ERYTHROCYTES
Red blood cells that have hemolyzed and hemoglobin aggregates can be identified on cytologic examination from vitrectomy and aqueous specimens [
1]. Ghost erythrocytes are red blood cells in which the bulk of the hemoglobin has been extruded, leaving behind small fragments of hemoglobin festooned along the cell membrane remnants. Ghost erythrocytes are important to identify because they may enter the anterior chamber angle, obstruct the trabecular meshwork, and produce ghost-cell glaucoma [
2]. Ghost-cell glaucoma has been reported after vitreous hemorrhage associated with cataract extraction or diabetic retinopathy [
3].
Ghost cells appear on cytologic preparations as small ovoid to circular rings with central clear areas corresponding to the absence of hemoglobin. The hemoglobin is clumped at the periphery of the cell-forming Heinz bodies (Figure 5-1). Hemoglobin spherules are spheres of hemoglobin varying markedly in size, some of which are smaller than normal erythrocytes and others three to five times the diameter of red blood cell (Figure 5-2). Like ghost cells, hemoglobin spherules may obstruct the trabecular meshwork and produce glaucoma. If ghost cells or hemoglobin aggregates are diagnosed by cytologic examination of an aqueous, vitrectomy may be indicated in aphakic patients to relieve glaucoma [
4].
PARS PLANITIS
Pars planitis is a condition in which cells and membranous veils are observed in the vitreous overlying the pars plana. This finding is termed “snowbanking.” [
5] The cause of the disease is unknown. It is usually bilateral and occurs in young individuals. The collection of vitreous cells may obscure visions. Occasionally, vitrectomy may be done if an infectious agent is sought or if the opacity is chronic and severely limits vision. Histologically, lymphocytes and macrophages are seen adjacent to hyper-plastic non-pigmented ciliary epithelium. In the chronic condition, membranes may form over the pars plana composed of collagen and scare spindle cells (Figure 5-3). Perivascular sheathing of lymphocytes may also be seen (Figure 5-4). Cytologic preparations show lymphocytes and macrophages enmeshed in fibroglial membranous fragment (Figure 5-5). There finding are not specific, and the diagnosis requires careful clinical correlation.
References:
1.
Grossniklaus HE, Frank KE, Farhi DC, Jacobs G, Green WR. Hemoglobin spherulosis in the vitreous cavity. Arch Ophthalmol 1988;106:961-962.2.
Campbell DG, Simmons RJ, Grant WM. Ghost cells as a cause of glaucoma. Am J Ophthalmol 1976;81:441-450.3. Campbell DG, Essigmann EM. Hemolytic ghost cell glaucoma. Arch Ophthalmol 1979;97:2141-2146. 4.
Brucker AJ, Michels RG, Green WR. Pars plana vitrectomy in the management of blood induced glaucoma with vitreous hemorrhage. Ann Ophthalmol 1978;10:1427-1437.5.
Pederson JE, Kenyon KR, Green WR, et al. Pathology of pars planitis. Am J Ophthalmol 1978;86:762-774.
