BACKGROUND: The complications of fine-needle aspiration cytology (FNAC) are rare but can be challenging for performing physicians to diagnose and manage. This type of procedure is perceived as routine and devoid of substantial risks, but uncommon complications can occur and need to be addressed with careful workup.

CASE REPORT: A FNAC procedure for a young female patient with multiple thyroid nodules was requested by her general practitioner. After the FNAC thyroid procedure, a carotid wall hematoma was suspected and could not be excluded with ultrasound (US) alone. Thus, the patient underwent a computed tomography angiogram (CTA) that excluded blood extravasation from the carotid, confirming the suspicion of perivascular blood accumulation. As a precaution, the patient was hospitalized, with US follow-up; she was dismissed the day after her hospital admission with a diagnosis of a benign thyroid nodule in multinodular goiter according to SIAPEC-IAP classification.

CONCLUSIONS: This case highlights how a routine-perceived procedure such as FNAC could present a challenge to the performing physicians, pathologist, and radiologist, raising the suspicion of a severe complication that needs to be addressed with a readily available emergency service that may be accessible only within a central hospital-level organization. This case reinforces the point that more careful adherence to clinic-radiological guidelines is needed to avoid potentially inappropriate and harmful procedures. A review of the literature concerning guidelines for FNAC procedure, diagnostic classifications, and reported complications is provided as part of this case report.

Keywords: Biopsy, Fine-Needle, Carotid Artery Injuries, Cytological Techniques, Thyroid Gland, Ultrasonography, Goiter, Guideline Adherence, Hematoma, Thyroid Nodule