Lymphangioma of the posterior mediastinum in an adult: diagnosis via cytopathologist-assisted fine-needle aspiration biopsy with cell block.

Lymphangiomas are uncommon in the posterior mediastinum. We report a case of a lymphangioma in this location that was diagnosed by computed tomographic-guided fine-needle aspiration biopsy. The cell block of the lesion closely simulated a normal structure immediately adjacent to the target and could have been misdiagnosed as "normal tissue." On-site evaluation of the aspirate by a cytopathologist promoted pathologist-radiologist communication that helped prevent the potential error and facilitated making the correct diagnosis in the case.