Ocular Cytopathology

An atlas that features the cytologic findings of the normal features and diseases of the eye.

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Tuesday, October 04, 2005


Schwannoma (Neurilemmoma)

Schwannomas are tumors of peripheral nerves that presumably arise from Schwann cells. They occur between the ages of 20 and 50 years and are associated with neurofibromatosis. [61]Clinically, patients frequently exhibit proptosis, lid swelling, diplopia, and indentation of the posterior sclera (Figure 10-39). [62] CT scan reveals that neurilemomas have round smooth borders and expand cortical bone (Figure 10-40). Fine needle aspiration of schwannoma is usually not diagnostic because scant material is obtained. However, myxoid areas associated with spindle cells and bent nuclei are suggestive of a neural lesion (Figure 10-41). Schwannomas are encapsulated and have a firm consistency (Figure 10-42). The tightly packed spindle cells form characteristic Antoni A and B areas that are difficult to discern in fine needle aspiration specimens (Figure 10-43). The cohesive architecture of the schwannoma accounts for the inadequate specimens previously reported. [8]


Meningiomas in the orbit presumably arise from the arachnoid tissue of the optic nerve and the meninges adjacent to the sphenoid and nearby intracranial structures. Clinical presentation is determined by location. Optic canal meningiomas compress the optic nerve and lead to early and profound visual deficits. [63] Radiologic findings may show well-defined soft-tissue lesions with hyperostosis when bone is involved. The optic nerve may show fusiform swelling, diffuse thickening, or globular enlargement. [64] Fine needle aspiration has been reported to effectively diagnose orbital meningiomas in 10 cases. [3, 8, 65, 66, 67, 68] Aspiration biopsy is appropriate for unresectable meningiomas if a tissue diagnosis is required for radiation therapy. Aspiration under CT guidance is helpful to place the needle in orbital apex and posterior meningiomas (Figures 10-44 and 10-45). Smears show oval and round cells organized in tight clusters and occasional whorls. The nuclei may have intranuclear inclusion (Figure 10-46). Rarely psammoma bodies are seen.


61. Izumi AK, et al. Von Recklinghausen's disease associated with multiple neurolemomas. Arch Dermatol. 1971 Aug;104(2):172-6.
62. Rootman J, Robertson WD. Tumors In: Rootman J, ed. Diseases of the orbit. Philadelphia: J.B. Lippincott, 1988:293-305.
63. Wilson WB. Meningiomas of the anterior visual system. Surv Ophthalmol. 1981 Nov-Dec;26(3):109-27.
64. Rootman J, Robertson WD. Tumors In: Rootman J, ed. Diseases of the orbit. Philadelphia: J.B. Lippincott, 1988:293-305.
65. Meyer E., et al. Fine-needle aspiration of orbital lesions. Ann Ophthalmol. 1983 Jul;15(7):635-8
66. Czerniak B., et al. Diagnosis of orbital tumors by aspiration biopsy guided by computerized tomography. Cancer, 1984 Dec 1;54(11):2385-9.
67. Zajdela A, et al. Cytologic diagnosis of orbital and periorbital palpable tumors using fine-needle sampling without aspiration. Diagn Cytopathol. 1986 Jan-Mar;2(1):17-20.
68. Cristallini EG, Fine needle aspiration biopsy of orbital meningioma. Report of a case. Acta Cytol. 1990 Mar-Apr;34(2):236-8.


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