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The effects on morphology and diagnostic interpretation of delayed processing of refrigerated effusion samples have not been well documented. The potential for cellular degeneration has led many laboratories to reflexively fix samples rather than submit fresh/refrigerated samples for cytologic examination. We sought to determine if effusion specimens are suitable for morphologic, immunocytochemical, and DNA-based molecular studies after prolonged periods of refrigerated storage time. Ten fresh effusion specimens were refrigerated at 4 degrees C; aliquots were processed at specific points in time (days 0, 3, 5, 7, 10, 14). Specimens evaluated included four pleural (3 benign, 1 breast adenocarcinoma) and six peritoneal (2 ovarian adenocarcinomas, 1 malignant melanoma, 2 mesotheliomas, 1 atypical mesothelial) effusions. The morphology of the cytologic preparations from the 10 effusions was preserved and interpretable after 14 days of storage at 4 degrees C. The immunocytochemical profile of the samples (AE1/AE3, EMA, calretinin, and LCA) was consistent from day 0 to day 14. Amplifiable DNA was present in all samples tested on day 14. We conclude that cytopathologic interpretation of effusion samples remains reliable with refrigeration at 4 degrees C even if processing is delayed.

Nephroblastoma (Wilms' tumor) is the most common childhood renal tumor and usually presents with a histology and cytology consisting of blastemal, epithelial, and stromal cells. Effusions are not uncommon and may suggest an unfavorable prognosis when containing anaplastic tumor cells. In the present case, we report the cytological appearance of a Wilms' tumor metastatic to the pleura. The effusion consisted primarily of tumor cells demonstrating epithelial differentiation. The tumor cells mostly presented as three-dimensional aggregates in an inflammatory background. Many cystic and tubular structures were identified. The tumor cells demonstrated strong CD56 and WT1 immunoreactivity. The histology of a subsequent surgical specimen reflected the features seen in cytology., ((c) 2006 Wiley-Liss, Inc.)

Use of the polymerase chain reaction (PCR) for the detection of B- and T-cell clonality, Epstein-Barr virus (EBV) and Human Herpes Virus 8 (HHV 8) infection is gaining increasing importance as a diagnostic modality. These tests are usually performed on fresh specimens. There are instances when fresh material is not available and there is a clinical utility for the performance of PCR on archival material via slide scrape lysates (SSL). However, the suitability of archival material may be questioned. Records were searched for all archival cytology cases submitted for SSL molecular diagnostics tests since 1998. Results for each case were analyzed for PCR amplification status and individual test results. A randomly chosen control group of equivalent cytologic samples submitted fresh was evaluated for comparison of amplification status. In all, 241 PCR runs were performed on SSL of archival material from 112 cytologic samples (89 cerebrospinal fluids (CSFs), 13 fine-needle aspirates (FNAs), 10 effusions). Out of these samples, 95 (85%) had amplifiable DNA, as assessed by a positive reaction for glyceraldehyde phosphate dehydrogenase (GAPDH). For the control group, 320 PCR runs were performed on 112 fresh cytologic samples (89 CSFs, 13 FNAs, 10 effusions). In total, 102 samples (91%) had amplifiable DNA. There was no statistical difference in the amplification yield between the two groups (P = 0.2177). A morphologic review of 16 of the 17 SSL archival cytologic cases that did not show amplification revealed 11/16 to be of sparse cellularity. Molecular diagnostic tests are performed routinely on fresh cytologic samples with excellent results. At times critical decisions on patient care may need to be made when fresh tissue is not available for molecular diagnostic tests. SSL of archival cytologic material can be used with excellent results for molecular diagnostic tests when fresh material is not available or when the cytologic diagnosis needs further clarification.

Discrepant results in effusion immunocytochemistry are often the result of specimen processing. Smears, cytospins, cell blocks, and monolayer preparations have all been used in various published studies; thus, there is no consistency in the immunostaining process for cytology to compare with the surgical pathology "gold standard" results. We sought to evaluate optimal specimen preparation for the immunostaining of effusion samples. Fourteen reactive and 15 malignant effusion samples (various epithelial/mesothelial neoplasms) were each prepared in three forms: air-dried cytospins (postfixed in ethanol), formalin-fixed, paraffin-embedded cell blocks, and liquid-based thin-layer (ThinPrep, CYTYC, Boxborough, MA) processing. All slides were immunostained with antibodies commonly used in effusion cytology: HBME-1, calretinin, E-cadherin, BerEP4, B72.3, LeuM1, and CA19-9. Cytospin and ThinPrep samples performed in a similar manner: high background staining was encountered in 66% of cases, most evident in three-dimensional clusters of cells. In addition, membrane staining patterns were difficult to interpret. Cell blocks provided the best milieu for morphologic interpretation, with less background staining (only 17% of cases) and results that most closely approximated those reported in the surgical pathology literature. The cost per test for cell block immunocytochemistry was also the most economical for our laboratory.