Branchial cleft‐like cysts in Hashimoto's thyroiditis: A case report and literature review

Abstract

We report an extremely rare case of branchial cleft-like cysts in Hashimoto's thyroiditis. The patient was a 77-year-old man with a growing mass in the anterior neck. Ultrasonography and computed tomography revealed a cystic lesion with septum in the left thyroid and multiple small cystic lesions in the right thyroid. Lymph node swelling of the cervical region, supraclavicular fossa and submandibular region was also observed. Left thyroidectomy and lymph node dissection were performed. Histologically, cysts were lined by stratified squamous epithelium and dense lymphoid tissue having conspicuous follicle formation surrounded the epithelial lining. Solid cell nest (SCN)-like aggregations were seen in the thyroid parenchyma adjacent to the cyst walls and a small number of thyroid follicles were observed in the fibrous wall. Immunohistochemically, it is suggested that both the cyst lining and SCN-like aggregations are originally from thyroid follicles. Although, the exact histogenesis of branchial cleft-like cysts remains unclear, there are probably two different processes for its development, one is of branchial cleft origin and the other is mere squamous metaplasia, while in our case the latter is suggested. Herein, we report our new case and update information about branchial cleft-like cysts that appears in the literature.

Thyroid FNA biopsies comprised of abundant, mature squamous cells can be reported as benign: A cytologic study of 18 patients with clinical correlation

“…One is follicular cells that have undergone squamous metaplasia, which typically is noted within the setting of inflammation and especially in a background of Hashimoto thyroiditis. Other intrathyroidal sources of benign squamous cells include developmental rests, most commonly thyroglossal duct, thymic, and lymphoepithelial/ultimobranchial body remnants . To our knowledge, epidermoid and dermoid cysts rarely have been reported in the thyroid as well .…”

“…Other intrathyroidal sources of benign squamous cells include developmental rests, most commonly thyroglossal duct, 6,8,9 thymic, 10 and lymphoepithelial/ultimobranchial body remnants. [5][6][7][11][12][13][14][15] To our knowledge, epidermoid and dermoid cysts rarely have been reported in the thyroid as well. [16][17][18] Patients with any of these entities may present with discrete thyroid nodules and undergo thyroid FNA.…”

Derivation of thyroid lymphoepithelial cysts from follicular cells

“…The lesions may originate from squamous metaplasia and cystic degeneration of solid cell nests and the enlargement may be related to the immunological mechanisms associated with autoimmune thyroiditis [13]. The lesion has been described as "branchial cleft-like cyst" [9,11,14,20]. An alternative theory, based upon derivation from follicular cells, has also been proposed.…”

“…An alternative theory, based upon derivation from follicular cells, has also been proposed. Miyazaki et al attributed the origin of LECs to squamous metaplasia of a cystic lesion which developed as a result of degeneration in a nodular goiter, or squamous metaplasia of the follicular cells associated with Hashimoto's disease [14].…”

“…It is suggested that the underlying pathologic process is squamous metaplasia and cystic degeneration of solid cell nests. The second hypothesis is that the pathogenesis of thyroid LECs derives from squamous metaplasia of follicular cells associated with Hashimoto's disease [14]. Here, we performed pathological and immunohistochemical examination of 21 thyroid LECs and compared these to squamous metaplasia of the thyroid, solid cell nests, and lateral cervical cysts.…”