Australian Society of CytologyCase of the Month
February 2003 - Answer and Discussion
Papillary carcinoma
) |
| Histology |
Discussion
Although not perfect, fine needle aspiration has proved to be the single most reliable pre-operative test in the management of patients with nodular thyroid disease. With regard to papillary carcinoma, fine needle aspiration of the thyroid is frequently diagnostic and papillary carcinoma is, in fact, generally held to be the least difficult thyroid malignancy to diagnose. Classical cytopathology features of papillary carcinoma include a cellular aspirate, papillary fronds, flat monolayered sheets of cells, dense blue/grey "metaplastic" cytoplasm, psammoma bodies, intranuclear inclusions, nuclear grooves, histiocytes and "chewing gum" colloid.
Cytologic findings have been described for several variants of papillary carcinoma. Cystic degeneration is not uncommon and is found in up to 44% of papillary carcinomas, typically altering the cytological findings. The aspirate tends to yield a background of cystic debris, macrophages and evidence of old haemorrhage, often with a paucity of epithelial material. The epithelial material that is present may show nuclear degeneration and cytoplasmic vacuolation making assessment difficult. Sparse papillary clusters of atypical cells showing evidence of nuclear overlap, plus or minus other diagnostic nuclear features may be the only clue. It is important to maintain a high degree of diagnostic suspicion in this setting and to be sure there has been adequate sampling, not only of cyst contents, but any residual solid areas. Should the "cyst" fail to resolve or re-accumulate, further investigation should be undertaken.
Further Reading:
- Rosai J, Carcangiu ML, DeLellis RA. Atlas of tumour pathology: Tumours of the thyroid gland. 3rd series. Fascicle 5. AFIP 1992; 65-122.
- Holleman F, Hoekstra JB, Ruitenberg HM. Evaluation of fine needle aspiration cytology in the diagnosis of thyroid nodules. Cytopath 1995; 6: 168-175.
