72 year old woman with a mediastinal mass and lymphadenopathy in the neck.  The bone marrow was not involved.

Mediastinal Mass and Lymphadenopathy

Figure 1-Low Power magnification of lymph node (40x magnification).


Figure 2-High power magnification (400x).

Figure 3-Tdt (400x magnification)

Figure 4-CD7 (400x magnification)


Figure 5-CD79a (400x magnification)


Figure 6-CD20 (400x magnification)


Figure 7-CD3 (400x magnification)

Figure 8-Myeloperoxidase (400x magnification)


Figure 9-Pax-5 (400x magnification)

Flow cytometry on a second lymph node biopsy performed at the treating hospital
revealed expression of CD5, CD7, CD10, CD33 and TdT.

What is your diagnosis?