The lymphoblasts have high nucleus:cytoplasm ratio, numerous mitoses, finely stippled chromatin and inconspicuous nucleoli. The nuclear contours may be round or convoluted. An atypical or large cell variant of lymphoblastic lymphoma has been described (approx. 10% of cases). In the absence of treatment, it pursues a rapid clinical course with rapid dissemination, development of acute lymphoblastic leukemia, and early death.