CT CT Fine Needle Aspiration Cytology 1 — Questions and Answers
Question 1: Which cytomorphologic feature is most important for assessing adequacy of a thyroid fine needle aspiration (FNA) specimen according to the Bethesda System for Reporting Thyroid Cytopathology?
- Presence of colloid
- At least 6 groups of well-preserved follicular cells with ≥10 cells per group (Correct answer)
- Absence of blood
- Presence of Hürthle cells
Correct answer: At least 6 groups of well-preserved follicular cells with ≥10 cells per group
A satisfactory thyroid FNA requires at least 6 groups of well-preserved follicular cells with a minimum of 10 cells per group, though exceptions apply for clearly malignant specimens.
Question 2: On FNA of a thyroid nodule, cells arranged in a 'honeycomb' sheet pattern with round nuclei and granular chromatin surrounded by abundant colloid are most consistent with which diagnosis?
- Papillary thyroid carcinoma
- Benign follicular nodule/adenomatoid goiter (Correct answer)
- Medullary thyroid carcinoma
- Anaplastic carcinoma
Correct answer: Benign follicular nodule/adenomatoid goiter
Benign follicular nodules show sheets of uniform follicular cells in a honeycomb arrangement with background colloid, flat nuclei, and absent nuclear grooves.
Question 3: Which combination of nuclear features is pathognomonic for papillary thyroid carcinoma (PTC) on FNA cytology?
- Nuclear molding and coarse chromatin
- Nuclear grooves, intranuclear pseudoinclusions, and powdery chromatin (Correct answer)
- Prominent nucleoli and vesicular nuclei
- Hyperchromatism with high N:C ratio
Correct answer: Nuclear grooves, intranuclear pseudoinclusions, and powdery chromatin
PTC is characterized by the triad of nuclear grooves (coffee bean nuclei), intranuclear cytoplasmic pseudoinclusions, and ground-glass/powdery chromatin (Orphan Annie nuclei).
Question 4: In breast FNA cytology, which finding is associated with a fibroadenoma rather than carcinoma?
- Single atypical cells with large irregular nuclei
- Tightly cohesive staghorn clusters ('antler' pattern) with bare nuclei in background (Correct answer)
- Three-dimensional clusters with loss of cohesion
- Necrotic debris in background
Correct answer: Tightly cohesive staghorn clusters ('antler' pattern) with bare nuclei in background
Fibroadenomas classically yield cohesive staghorn/antler-like epithelial clusters, stromal fragments, and bare bipolar nuclei in the background without single atypical cells.
Question 5: FNA of a neck mass in a 30-year-old yields fluid with cholesterol crystals, anucleate squamous cells, and amorphous debris. What is the most likely diagnosis?
- Thyroglossal duct cyst
- Branchial cleft cyst (Correct answer)
- Lymphoma
- Metastatic squamous cell carcinoma
Correct answer: Branchial cleft cyst
Branchial cleft cysts classically yield turbid fluid containing anucleate squamous cells, cholesterol crystals, and keratinous debris without malignant cells.
Question 6: Which stain is routinely used to perform a rapid on-site adequacy assessment during FNA procedures to guide immediate specimen triage?
- Papanicolaou stain
- Hematoxylin and eosin
- Diff-Quik (modified Romanowsky) stain (Correct answer)
- Mucicarmine stain
Correct answer: Diff-Quik (modified Romanowsky) stain
Diff-Quik is an air-dried rapid stain that allows on-site adequacy evaluation within minutes, enabling immediate assessment of cellularity and preliminary diagnosis.
CT CT Fine Needle Aspiration Cytology 1
Which cytomorphologic feature is most important for assessing adequacy of a thyroid fine needle aspiration (FNA) specimen according to the Bethesda System for Reporting Thyroid Cytopathology?