Usefulness Of Touch Preparation Cytology In Postmortem Diagnosis: A Study From The University Hospital Of The West Indies

摘要

Touch preparation or imprint cytology has been shown to be of value in the diagnosis of surgical pathology specimens and a few studies have also suggested a role in postmortem examination. The use of the technique in postmortem diagnosis has not been previously reported from a developing country. We prospectively examined 40 autopsy cases (M:F ratio 1.2:1, mean age 50.7 +/- 22.3 years) at the University Hospital of the West Indies with touch preparation cytology in addition to routine histology. A total of 120 specimens were obtained from a wide range of organs with the cytologic diagnosis being malignant in most cases (75 %); the overall concordance between cytologic and histologic diagnoses was 92.2%. Touch preparation cytology proved to be an accurate, simple, fast and relatively inexpensive method of postmortem diagnosis, and is likely to be of particular value in areas where cost-containment is critical. Introduction In a landmark paper published in 1927, Dudgeon and Patrick first described the use of imprint smears of fresh tissues in the rapid microscopical diagnosis of tumours 1. Subsequently, various publications have addressed the application of imprint or touch preparation cytology in the diagnosis of surgical specimens including intraoperative diagnosis 2,3,4,5,6,7. The application of the technique in postmortem examinations has received far less attention, although the few publications on the subject have noted its potential value including much cheaper preparation costs relative to routine histologic sections 8,9,10.The use of touch preparation cytology in postmortem diagnosis has not been previously reported from a developing country, and in an era in which cost-containment has become a critical factor in the operation of medical facilities in regions such as ours, we sought to investigate the diagnostic accuracy and usefulness of touch preparation smears in postmortem examinations at the University Hospital of the West Indies (UHWI). Material and Methods In a prospective study performed at the UHWI between May 1999 and November 2001, 40 autopsy cases (15 medicolegal/coroner’s and 25 hospitalon-coroner’s cases) were subjected to cytologic evaluation in addition to routine histology. The study investigators were notified by pathology residents when autopsies were being performed on patients with mass lesions or suspected tumours amenable to touch preparation cytology smears. Relevant clinical and gross autopsy findings were recorded using a pre-designed abstraction form. A total of 120 specimens were obtained from various sites as shown in Table 1. The slides were prepared either by making direct imprints of the cut surface of the selected tissue, or by scraping the cut surface with an edge of a glass slide prior to imprinting, the latter technique being used for firm to hard tissues including bone marrow to facilitate cell removal 9. The slides were then placed immediately in 95% ethyl alcohol and stained by the routine Papanicolaou method. In some cases immediate assessment of the smears was also performed using a rapid Papanicolaou method 11, with the rapid diagnosis facilitating the immediate sampling of additional organs.Tissue sections were also taken for histologic evaluation in most cases; bone marrow sections were not taken. The tissue sections were fixed in 10% buffered formalin, routinely processed, embedded in paraffin, and stained with hematoxylin-eosin. Immunohistochemical studies were performed for cases diagnosed microscopically as malignant lymphoma using a modified avidin-biotin peroxidase complex (ABC) method with a panel of standard lymphoma antibodies.Cytologic diagnoses were classified as benign, indeterminate, suspicious for malignancy and malignant. Due to the nature of the sampling i.e. smears of the surfaces of whole masses/organs, there were no inadequate samples. The overall concordance between cytologic and histologic diagnoses was determined. Results The 40 patients included in the