DEC 09, 2011
By Matthew W. Wilson, MD, FACS
Ocular Pathology/Oncology
The authors describe in this retrospective case series published in November in the American Journal of Ophthalmology their pathologic evaluation of iris and iridociliary tumor biopsy samples obtained with an aspiration cutter technique. They found that although specialized pathologic techniques were necessary to maximize material available for diagnosis, all 56 biopsies yielded cellular material and 41 percent yielded diagnostic tissue in cell-block preparation. Diagnostic yield was 98.2 percent, which is lower than that of wide incisional or excisional biopsy.
The authors conducted aspiration-assisted biopsies in 55 patients (55 eyes) with iris and iridociliary tumors. They obtained undiluted specimens from each biopsy and made ctyospin and cell-block preparations for each specimen.
Specimen cellularity was adequate for cytopathologic diagnosis in 55 biopsies (98.2 percent). Twenty-three specimens (41 percent) had diagnostic material in the cell block allowing for further bleaching and immunohistochemical staining when necessary. Wide incisional or excisional biopsy confirmation was available in 13 biopsies (23.2 percent), with cytopathologic diagnoses consistent with histopathologic diagnosis in 12 of these cases.
The authors say that bleached preparations and immunohistochemical stains obtained on paraffin-embedded tissue were particularly valuable in distinguishing darkly pigmented melanomas from melanocytomas and pigmented ciliary body epithelial tumors. Immunohistochemical stains on cytospin and cell-block preparations were useful in establishing the diagnosis of adenocarcinoma of ciliary body epithelium, lymphoma and metastatic carcinoma.
Despite the advantages of obtaining a relatively large specimen for pathologic evaluation, aspiration cutter-assisted biopsies still resulted in one nondiagnostic specimen and one misdiagnosis. Review of the original cytologic and retrospective immunohistochemical stains on cytospin and cell-block preparations in these cases led to amended diagnoses. The authors conclude that both of these cases highlight the importance of careful cytologic evaluation and the benefit of immunohistochemical stains in establishing the correct diagnosis.
They say that the accuracy of cytopathologic diagnosis was aided greatly by the availability of clinical data. For example, clinical observation of locally aggressive behavior of ciliary body epithelial neoplasm led to a cytopathologic diagnosis of low-grade adenocarcinoma as opposed to adenoma. Similarly, familiarity with patients' oncologic history led to a confirmation of metastatic disease in one case, a diagnosis of invasive ocular surface epithelial neoplasm in one case and the diagnosis of degenerative iris lesions in three cases.