Thymoma, Lymphocyte-Rich, Mimicking T-ALL

Lessons From the Friday Unknowns

The patient presented with newly identified large right lung mass and an unremarkable complete blood count.

Touch imprints of the biopsy specimen show numerous intermediate lymphoid cells with oval nuclei, fine chromatin, small nucleoli and scant cytoplasm, in a background small mature lymphocytes.

Histologic sections show small fragments of tissue composed of numerous small lymphoid cells with fine chromatin and occasional large cells with pale chromatin.