Fine Needle Aspiration Cytology of Postoperative Spindle Cell Nodule in Neck after Thyroidectomy: A Case Report

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/ by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Although postoperative spindle cell nodules have occasionally been found in the lower genitourinary tract, 1-3 their presence in post thyroidectomy sites has been reported in only one case. 4 In addition, diagnosis by fine needle aspiration (FNA) has not been established. Here, we report on characteristic cytologic findings for a post-operative spindle cell nodule arising in the post-thyroidectomy site. A 53-year-old female patient visited the hospital for evaluation of an asymptomatic right lateral neck mass. She had undergone a right thyroid lobectomy for treatment of a papillary mi-crocarcinoma 22 months prior. The tumor measured 0.7×0.6 cm in size with a clear resection margin. After the operation, she was followed regularly, and there were no events. A hypoechoic mass with multiple calcifications was observed on thyroid ultrasonography, and ultrasonography guided-FNA was performed. The smear of the FNA cytology showed fragments of fibrocollagenous connective tissue and scattered spindle cells (Fig. 1A). Some histiocyte-like cells were aggregated forming vague granulomas (Fig. 1B, C). Loosely scattered young fibroblast-like cells with plump nuclei were observed (Fig. 1D). The cytologic diagnoses were suggestive of nodular fasciitis or a granulomatous reaction to a foreign body. The patient had undergone a complete thyroidectomy and neck mass excision. Severe adhesions were observed in the post-operative thyroid bed, and the residual thyroid left lobe was normal in appearance on gross examination. Grossly, the neck mass measured 4.3×3.5×2.6 cm, with a round, firm, and whitish surface. The cut surface was a homogenous yellow-tan color and was focally hemorrhagic (Fig. 2A). There were no pathologic findings in the thyroid left lobe. Microscopically, the mass was found to be composed of bland-looking spindle cells (Fig. 2B), with an indistinct cell border, eosinophilic cytoplasm, and oval nuclei. The nucleoli were inconspicuous (Fig. 2C). Mitotic counts were 6 per 10 high power field without atypism (Fig. 2C, inset). Adhesions on adjacent structures were observed, but did not show an infiltrative pattern. The spindle cells were fully reactive in vimentin (prediluted, DISCUSSION Postoperative spindle cell nodules in the thyroidectomy bed are extremely rare. 4 According to the literature, the reported sites of postoperative spindle cell nodule included the genito-urinary tract, oral cavity, breast, and skin. Except for cases arising …