Translate case to... METASTATIC PAPILLARY THYROID CARCINOMA DIAGNOSED BY FINE NEEDLE ASPIRATION OF A BRANCHIAL CLEFT CYST.

A 32-year-old, pregnant woman presented a laterocervical mass of 10 months’ evolution. The patient had undergone various FNA procedures, which yielded a dense, brownish material. A diagnosis of metastatic pappillary carcinoma of probably thyroid origen was made.
Surgery was carried out and the cervical mass was identified as a branchial cyst with metastatis papillary carcinoma. Total thyroidectomy showed that the 6-mm nodule corresponded to PAPILLARY THYROID CARCINOMA (PTC).

Comments: FNA cytology of cyst showed pigmented macrophages and a granular background together with cohesive cluster. Tumor cells with ground glass appearance, overlapping nuclei, nuclear grooves, intranuclear inclusions, psammoma bodies and some multinucleated cells were seen. Immunocytochemical stain for thyroid transcription factor 1 (TTF1) was positive. The diagnosis was metastatic PTC.
Histological examination of the cervical mass was identified as a branchial cleft cyst with metastatic PTC in the wall. TTF1 and thyroglobulin stains were positive in the tumor. No ectopic thyroid tissue was found.
The piece of thyroidectomy had a nodule of 6 mm corresponded to PTC.

The literature contains reports of cystic cervical lesions of a varying nature diagnosed by FNA as PTC. This is not the case of branchial cysts. In 6 published cases in which FNA was performed, only one was reported as malignant; in the remaining cases, a dense brownish material with cholesterol crystals was obtained. To achieve a correct preoperative study in cases of branchial cyst with metastatic PTC, it could be of great help to perform ultrasound-guided FNA sampling of the cyst wall, above all in cases with brownish material obtained in previous FNA.

Comments: FNA cytology of cyst showed pigmented macrophages and a granular background together with cohesive cluster. Tumor cells with ground glass appearance, overlapping nuclei, nuclear grooves, intranuclear inclusions, psammoma bodies and some multinucleated cells were seen. Immunocytochemical stain for thyroid transcription factor 1 (TTF1) was positive. The diagnosis was metastatic PTC.
Histological examination of the cervical mass was identified as a branchial cleft cyst with metastatic PTC in the wall. TTF1 and thyroglobulin stains were positive in the tumor. No ectopic thyroid tissue was found.
The piece of thyroidectomy had a nodule of 6 mm corresponded to PTC.

The literature contains reports of cystic cervical lesions of a varying nature diagnosed by FNA as PTC. This is not the case of branchial cysts. In 6 published cases in which FNA was performed, only one was reported as malignant; in the remaining cases, a dense brownish material with cholesterol crystals was obtained. To achieve a correct preoperative study in cases of branchial cyst with metastatic PTC, it could be of great help to perform ultrasound-guided FNA sampling of the cyst wall, above all in cases with brownish material obtained in previous FNA.