Prospective Study

Cell blocks derived from fine-needle aspirates of tumors as an alternative to surgical biopsies in cats and dogs

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Abstract

Cytology and histopathology are commonly used in the diagnosis of suspected neoplasia in companion animals. A prospective study was performed to evaluate the added diagnostic value of the cell block (CB) technique applied to fine-needle aspirate biopsy (FNAB) samples from dogs and cats with suspected neoplastic masses, compared with conventional cytology and histopathology. The study included 41 masses excised from 39 animals (35 dogs, 4 cats). Fine-needle aspirate biopsy samples were collected ex vivo for cytology and CB preparation before routine histopathologic examination, which served as the reference standard. Cytology samples were completely or partially diagnostic in 29/41 cases (70.7%), whereas CB analysis was completely or partially diagnostic in 34/41 (82.9%). The CB aided the diagnosis in 15/20 cases that were non-diagnostic or only partially diagnostic based on cytology samples. When the sample was sufficiently cellular (34/41), CB diagnoses were consistent with histopathology in 94.1% (32/34) of cases. Combining cytology and CB increased the overall diagnostic yield to 90.2% (37/41). In this study, the CB technique substantially enhanced the diagnostic yield of FNAB, and combined with cytology, may reduce the need for more invasive surgical biopsies in selected cases.