Background: Ectopic hamartomatous thymoma is a rare, benign tumor occurring exclusively in the supraclavicular and suprasternal regions. To the best of our knowledge, there are no English-language reports on its cytologic findings.
Case: A fine needle aspiration specimen from a mass in the suprasternal region in a 63-year-old male revealed epithelial cell nests, spindle cells, a cluster of mature adipocytes and a small number of lymphocytes.
Conclusion: Although ectopic hamartomatous thymoma is very rare, fine needle aspiration cytology may contribute to the correct diagnosis in conjunction with the characteristic clinical findings.