Two Ectopic Hamartomatous Thymomas of Suprasternal Region of the Neck in A Single Patient: A Case Report

Abstract

ABSTRACT Ectopic hamartomatous thymoma is a rare, generally benign neoplasm that mainly arises in the lower neck region and is yet to be completely understood. Herein, we describe a case with two separate and sequential growing neoplasms for the first time, distinguished from other reported solitary cases. A 58-year-old Chinese male presented with a 6-month history of two nontender, self-palpated masses in the suprasternal region of his neck. Physical examination revealed two masses with diameters of 5 cm and 2 cm. Ultrasound examination 2 years ago revealed a hyperechoic mass with a fat-derived possibility. These two neoplasms were clinically diagnosed as lipomas without other radiological examinations and were completely excised. Microscopically, they were well circumscribed and characterized by admixture with spindle cells, epithelial nests, and adipocytes in variable amounts, without atypia or mitotic activity. Immunohistochemical staining revealed that both neoplasms showed a biphasic pattern, with an epithelial nature with strong and diffuse positive expression of cytokeratin (CK) and myoepithelial differentiation with CK5/6 and p63 positivity in the spindle cells. There was no evidence of recurrence after a 28-month follow-up period. In this report, we present a unique case of ectopic hamartomatous thymoma to show the existence of multiple tumors in this rare disease. We hope to raise the awareness of the possibility of this disease when the tumor rises in typical lower neck regions, especially when mixed soft tissue or fat components are shown by imaging examination.