Needle Tract Implantation of Follicular Neoplasm After Fine-Needle Aspiration Biopsy: Report of a Case

Abstract

We herein report a 28-year-old woman with a follicular neoplasm showing subcutaneous needle tract implantation. One month after fine-needle aspiration biopsy (FNAB) for a tumor measuring 2.5 cm, the patient became aware of a subcutaneous nodule measuring about 1 cm at the needle insertion site. FNAB smear of this nodule showed poorly cohesive clusters of follicular cells with nuclear crowding, overlapping and resetting with some microfollicular architecture. Total thyroidectomy and resection of the subcutaneous nodule were performed. Although there was no capsular or vascular invasion of the nodule, the lesion was diagnosed as follicular carcinoma because of the subcutaneous seeding. Ki-67 labeling indices of the thyroid nodule and implanted tumor were higher than 5%. Furthermore, although galectin-3 was completely negative in the thyroid nodule, it was heterogeneously positive in the implanted tumor. It is therefore suggested that high cell proliferating activity as a characteristic of the original nodule and the subsequently obtained invasive characteristic of the implanted tumor contributed to this event. To date, there has not been any recurrence of the implanted lesion. Because implanted follicular carcinoma can be surgically removed, this complication should not impair the usefulness of FNAB.

Distant and Lymph Node Metastases of Thyroid Nodules with No Pathological Evidence of Malignancy: A Limitation of Pathological Examination

“…This event was observed in 0.17% of patients who were pathologically diagnosed as benign nodular goiter with no signs of carcinoma or follicular adenoma lesions. We previously reported a case of follicular neoplasm showing the growth of subcutaneous nodule by FNAB seeding [7]. Although it was diagnosed as follicular carcinoma based on FNAB seeding, there were no malignant findings in the thyroid on pathological examination of the total thyroidectomy specimen, thus the lesion would be diagnosed as nodular goiter unless such a finding is present.…”

Needle tract seeding: An avoidable complication

“…37,41,42 Generally, needle tract seeding appears earlier in poorly differentiated tumors and tumors of higher grade. 8 Sometimes, it may be difficult to distinguish between tumor recurrence and implantation metastasis as both may produce tumor markers.…”

Basic techniques in endoscopic ultrasound-guided fine needle aspiration for solid lesions: Adverse events and avoiding them

“…Limited data suggest that tumor seeding correlates with important clinical outcomes including tumor stage, prognosis, resectability, resection margin status, recurrence and survival. [5253545556575859606162] Others report a lack of correlation between tumor seeding and clinical outcomes. [63646566]…”