Collision Tumor of the Thyroid Gland: Primary Squamous Cell and Papillary Thyroid Carcinoma

Abstract

Introduction. Collision tumor of the thyroid gland is defined when independent and histologically distinct tumors coexist within the gland. The presence of both papillary and squamous cell carcinoma in the thyroid gland is unusual. Suggested etiologies include embryonic remanents of squamous epithelium, chronic inflammation, or thyroid malignancies promoting squamous metaplasia. Case Presentation. An elderly patient presented with a rapid enlargement of a long-standing right thyroid nodule. The tumor was locally invasive and unresectable. Pathology revealed the diagnosis of papillary and squamous cell carcinoma of the thyroid gland. Possible primary sites for squamous cell carcinoma in upper aerodigestive tract were excluded. The patient outcome was fatal although palliative chemoradiotherapy. Discussion. Collision tumor of papillary and squamous cell carcinoma of the thyroid gland is a rare entity that may imply bad prognosis, as to the presence of the squamous portion. The best treatment includes resection of the tumor; unfortunately it is not possible in most cases.

Collision tumors of the thyroid: A case report and review of the literature

“…In this report, we present the rare case of a collision tumor consisting of a native papillary thyroid malignancy abutting a squamous cell carcinoma (SCC). To our knowledge, this is the second such case reported in the literature . We also review the literature and present known collision and mixed tumors of the thyroid, outlining their constituents and natural history.…”

Collision carcinoma of squamous cell carcinoma and small cell neuroendocrine carcinoma of the larynx: A case report and review of the literature

“…Most head and neck collision carcinomas occur in the thyroid, with only a few being seen in the larynx[4]. Based on our definition of collision carcinoma, we found a total of 12 cases in the English-language literature from 2000 to 2018 (key words: collision carcinoma, head and neck; or collision tumor, head and neck)[1,2,5,16-24]. Of these recent cases, seven were male and five were female.…”

“…In eight (66.6%) cases[1,2,16,18-20,22,23], only one carcinoma was detected during the preoperative biopsy. Two cases[5,24] did not undergo a preoperative biopsy or had a failed biopsy. In only two (16.7%) of the 12 cases, the two components were successfully detected during the preoperative biopsy[17,21].…”

Collision tumour; Papillary thyroid cancer colliding with squamous oesophageal cancer

“…Primary squamous cancers of the thyroid gland are very aggressive tumors and typically present with a high incidence of pressure symptoms such as dysphagia and dyspnea 4 . They are extremely rare and account for less than 1% of all thyroid neoplasms 5 .…”