Faculty Bibliography

Extracardiac rhabdomyoma is an uncommon benign striated muscle tumor with a predilection for the head and neck region. However, it is extremely rare for extracardiac rhabdomyoma to present as a thyroid nodule. We report a case of rhabdomyoma diagnosed by thyroid fine-needle aspiration (FNA) in a patient with Birt-Hogg-Dubé (BHD) syndrome. A 60-year-old man with BHD syndrome presented for recurrent pneumothorax. Chest CT incidentally identified a thyroid nodule. Subsequent sonography confirmed a 4.44 × 2.28 × 2.82 cm solid, hypoechoic nodule with smooth margins in the right upper pole. Ultrasound-guided FNA revealed many clusters and scattered isolated large polygonal cells with abundant granular cytoplasm and small peripherally located nuclei. Vague striations in the cytoplasm were focally identified. No follicular cells or colloid was present. Immunocytochemistry on one direct smear slide demonstrated diffuse positivity for desmin, supporting muscular differentiation. Subsequent surgery identified an adult rhabdomyoma originating from the inferior constrictor muscle of the neck and anteriorly displacing the thyroid. Because the mass was intimately associated with the thyroid gland, it was initially mistaken for a thyroid nodule on ultrasound. Diagnosis of rhabdomyoma on FNA is challenging, especially when rhabdomyoma mimics a thyroid nodule on imaging. The differential diagnosis includes Hurthle cell neoplasm, granular cell tumor, colloid nodule, and normal striated skeletal muscle. Adequate radiologic data and familiarity with the cytologic features of rhabdomyoma are critical for an accurate diagnosis.

BACKGROUND:Differentiating parathyroid from thyroid lesions can be difficult on fine-needle aspiration (FNA) due to overlapping cytomorphologic features. While the traditional parathyroid hormone (PTH) assays can help in the distinction, these tests may be cumbersome, particularly when the lesion is unexpected clinically and a needle wash is not collected at the time of FNA. Therefore, we chose to investigate the application of immunohistochemical staining (IHC) with GATA 3 and thyroid transcription factor-1 (TTF-1) on air-dried cytology smears to distinguish parathyroid and thyroid lesions. METHODS:Air-dried touch preparation (TP) slides were prepared from consecutively selected parathyroid and thyroid specimens. Thirteen FNA cases with the clinical concern for parathyroid lesions were also included in the study. IHC was performed on unstained and ultrafast Papanicolaou (UFP) stained air-dried slides. RESULTS:On TP slides, GATA 3 expression was observed in all cases of parathyroid origin but no immunoreactivity was present in thyroid lesions. TTF-1 expression was observed in all cases of thyroid origin but not in parathyroid lesions. GATA 3 and TTF-1 expression of 13 FNA cases were consistent with the clinical impression or concurrent PTH tests. CONCLUSIONS:IHC with GATA 3 and TTF-1 on air-dried cytology smears is a simple and effective way to differentiate parathyroid vs thyroid lesions on FNA. Air-dried unstained and UFP-stained slides perform equally well with IHC, but UFP-stained slides provide the added benefit of morphologic evaluation and assessment of smear cellularity prior to IHC.

Papillary thyroid carcinoma (PTC) is generally associated with an excellent long-term outcome. Distant metastasis is rare with only 5-7% of patients developing distant disease. Metastasis of PTC to the pancreas is an exceedingly rare occurrence. To date, few cases have been reported. We present the case of an 81-year-old man with past medical history of PTC status post total thyroidectomy with local recurrence treated with radioactive iodine and selective neck dissection. Ten years after his initial diagnosis, PET-CT scan revealed a new hypermetabolic 1.1 cm × 0.9 cm left lower lobe lung nodule and hypermetabolism in the proximal body of the pancreas. Follow-up MRI cholangiogram showed a 1.0 × 0.8 cm T1 hypointense lesion in the proximal body of the pancreas. Endoscopic ultrasound-guided fine-needle aspiration biopsy of the pancreatic mass showed neoplastic epithelial cells arranged in papillary clusters with fibrovascular cores and syncytial sheets with high nuclear to cytoplasmic ratio, visible nucleoli, nuclear pallor, focal nuclear grooves, and rare intranuclear pseudoinclusions. Immunohistochemical stains performed on the smears showed positive nuclear expression of TTF-1 and PAX-8. The findings were consistent with metastatic PTC. Surgical resection of the lung nodule confirmed metastatic PTC. Pancreatic metastases usually occur after long time intervals with reports of up to 8 years in PTC. This makes the diagnosis more challenging, and metastatic disease should always be in the differential diagnosis in cases presenting with a pancreatic mass, especially in patients with a prior malignancy.

OBJECTIVE:Because of the indolent nature of Noninvasive Follicular Thyroid Neoplasm with Papillary-Like Nuclear Features (NIFTP) and potential requisite for conservative treatment, it is crucial to identify features of this entity pre-operatively. Our group recently published our findings that there are several cytomorphologic features that may be used as clues to distinguish NIFTP, PTC and follicular adenoma (FA) on fine-needle aspiration (FNA). Therefore, we aimed to determine the interobserver reproducibility of these findings. METHODS:Pre-surgical FNA slides from NIFTP (n=30), classic PTC (n=30) and FA (n=30) collected from 1/2013-8/2016 were reviewed by 7 cytopathologists blindly. Presence of selected cytomorphologic features was recorded and compared to determine percent agreement and inter-rater reliability among study cytopathologists using Gwet's AC1 statistics. RESULTS:For all the cytomorphologic features, the overall percent agreement amongst the pathologists ranged between 65.1% and 86.8% (Gwet's AC1 0.30 to 0.80). There was substantial or almost perfect agreement (Gwet's AC1 >0.60) in seven cytomorphologic features in the classic PTC group, in six features in the NIFTP group, and in five features in the FA group. There were no features with poor agreement (Gwet's AC1<0.0). CONCLUSIONS:The current study supports the reproducibility of our previous findings. The high level of agreement amongst pathologists for these groups, and particularly the NIFTP group, supports the notion that when viewed in combination as a cytologic profile, these cytomorphologic features may assist the cytopathologist in raising the possibility of NIFTP pre-operatively. This can potentially aid clinicians in deciding whether more conservative treatment may be appropriate.

BACKGROUND: The success of cell block preparation is crucial for ancillary diagnostic tests in cytology. However, achieving an optimal cell block can be challenging. The current study describes a self-clotting-based technique for fine-needle aspiration (FNA) cell block preparations and evaluates its usefulness in comparison with the conventional needle wash technique. METHODS: The clinical data, FNA procedure, and cellularity of cell blocks of the self-clotting group (37 cases) and the conventional needle wash group (33 cases) were compared. The cellularity was evaluated using a scoring system (0 indicated acellular, 1 indicated 1-50 cells, and 2 indicated >50 cells). RESULTS: Approximately 76% of cases in the self-clotting group received a score of 2 versus 36% in the conventional needle wash group. Approximately 14% received a score of 1 in the self-clotting group compared with 9% in the conventional needle wash group, whereas 11% in the self-clotting group received a score of 0 versus 55% in the conventional needle wash group. The differences between the 2 methods were statistically significant. CONCLUSIONS: The results of the current study demonstrate that the self-clotting method is superior to the conventional needle wash method for FNA samples. Cancer Cytopathol 2017. (c) 2017 American Cancer Society.