Читать книгу Modern Techniques in Cytopathology - Группа авторов - Страница 23

Cell blocks offer several advantages. By capturing small tissue fragments, the histologic architecture of a targeted lesion may be preserved. For instance, features such as intracellular bridging in squamous cell carcinoma or fibrovascular cores in papillary lesions are best appreciated on a cell block. Cell blocks also provide better examination of minute tissue fragments, which may be too thick to see on a smear or LBC preparation. A cell block can enhance the diagnostic yield of an FNA or cytology sample, especially when the cell block is made with residual or unused specimen remaining in a vial after making smears or LBC preparation slides [2–4]. A cell block can generate numerous recut slides for ancillary studies including cytochemical stains, immunohistochemical (IHC) stains and molecular testing by fluorescent in situ hybridization, polymerase chain reaction, and next-generation sequencing. Cell blocks are also a source of preparing additional recut slides for submission to another institution, enrollment into clinical trials, and future academic studies that do not compromise the original smears or LBC slides. Ordering ancillary studies from cell blocks, in contrast to using smears, integrates more easily into the existing workflow of the histology laboratory.

Although cell blocks offer many advantages, they are best used to complement rather than entirely replace other cytology preparations such as smears or LBC slides. A well-prepared smear or LBC sample can reveal cytologic detail that may not be well demonstrated in a cell block. For instance, Papanicolaou-stained cytology slides may highlight subtle nuclear features of a lepidic predominant lung adenocarcinoma, or cytoplasmic “orangeophilia” specific for squamous differentiation. Also, the lymphoglandular bodies seen in lymphoma cases or the tigroid background in seminoma or Ewing sarcoma best shown on Diff-Quik-stained cytology smears will not be appreciated in the cell block slides.