SMALL-CELL TUMORS
Fine needle aspiration is an excellent way to categorize small-cell tumors. However, further specification requires more extensive immunocytochemical or electron microscopic evaluation.
RhabdomyosarcomaOrbital rhabdomyosarcoma is the most common primary malignant orbital neoplasm in children. [
4, 5] It often presents as a rapidly expanding lesion in the orbit and occurs most commonly at about age 6 or 7 (Figure 10-1). [6,
7] Fine needle aspiration smears show a small-cell tumor with scant cytoplasm (Figure 10-2). Rhabdomyosarcoma of the orbit has been reported to be specifically diagnosed in at least six previous cases with fine needle aspiration biopsy. [
3,
4, 5, 6,
7,
8,
9,
10] In two other cases, a cytologic diagnosis of malignancy could be made, but not further specified. [
9] To maximize the diagnostic potential of orbital aspiration cytology, other techniques, such as immunocytochemistry for desmin, actin, and myosin, or electron microscopic demonstration of myofibrils, are often required (Figure 10-3). [
10] If a specific diagnosis can be made, fine needle aspiration has the advantages of being rapid and avoiding open biopsy. Radiation and chemotherapy are successful in 90% of cases. [
11]
Reactive Lymphoid HyperplasiaIf one excludes basal-cell carcinomas, lymphoid lesions are the most common tumors in series of orbital fine needle aspiration. [
8,
9]
Benign reactive lymphoid hyperplasia is a pathologic diagnosis given to orbital and periorbital lymphoid infiltrates that demonstrate germinal centers with tangible body macrophages and a heterogenous population of cells, including small lymphocytes, reactive lymphocytes (immunoblasts), and plasma cells. This diagnosis is made by identification of the heterogenous lymphoid elements. Architecture (diffuse or nodular) cannot be discerned in fine needle aspirates (Figure 10-4). Five percent to 25% of patients with the histologic appearance of a reactive process will eventually develop systemic lymphoma. [
12] Lesions intermediate between benign reactive lymphoid hyperplasia and lymphoma have been called atypical lymphoid hyperplasia. These lesions have irregular follicles, more atypical lymphocytes, and perhaps a slightly worse prognosis. [
13] However, reactive lesions by morphologic and immunophenotypic criteria may harbor clones of proliferating B cells. [
14,
15] These clones are identified on Southern blots as nongermline bands that have the same size DNA fragments when cleaved by restriction endonucleases and hybridized to radioactively labeled probes from specific sites on the immunoglobulin gene. [
16,
17,
18,
19,
20] It is becoming evident that orbital lymphoid lesions are a spectrum of B-cell neoplasias. [
21] Because no specific morphologic, immunophenotypic, or molecular criteria have yet been well correlated with eventual outcome, it is not clear what investigative procedures are required in order to manage patients with lymphoid lesions. If treatment is to be based on clinical criteria, then fine needle aspiration biopsy with or without phenotyptic markers will suffice. However, if the type of treatment is predicated on gene rearrangement studies, then at this time open biopsy with removal of adequate tissue is necessary.
References:
4.
Frayer WC, Enterline HT. Arch Ophthalmol 1959;62:203-210.5. Kirk RC, Zimmerman LE, Rhabdomyosarcoma of the orbit. ARch Ophthalmol 1969;81:559-564.
6. Yanoff M, Fine BS. Ocular pathology. Philadelphia: J.B. Lippincott, 1989:532-534.
7.
Knowles DM, Jakobiec FA, Potter G, Jones IS. Surc Ophthalmol 1976;21:219-261.8.
Kennerdell JS, Slamovits TL, Dekker A, Johnson BL. Am J Ophthalmol 1985;99:547-551.9.
Zajdela A, Vielh P, Schlienger P, Haye C. Am J Clin Pathol, 1990;93:100-104.
10.
de Jong ASH, can Kessel-van Vark M, van Heerde P. Acta Cytol 1987;31:573-577.11.
Wharam M, Beltangady M, Hays D, Heyn R, Ragab A, et al. Ophthalmology 1987;94:251-254.12.
Jakobiec FA, McLean I, Font R. Ophthalmology 1979;86:948-966.13.
Knowles DM II, Jakobiec FA. Cancer 1980;46:576-589.
