Diagnosis: Follicular lymphoma grading
• The lymphoma in the photomicrograph shows a distinct nodular growth pattern with expansion of follicle centers. The follicle centers show loss of polarization and tingible body macrophages. These findings are consistent with follicular lymphoma (FL).
• Degree of cellular atypia (A), number of apoptotic bodies (B), and number of mitoses (C) play no role in grading of FL.
• Centroblastic cells, not cetrocytic cells (E), are counted in multiple high power fields and the grade is determined based on the average count (grades 1 to 2 have 15 or more centroblasts per HPF; grade 3 has more than 15 centroblasts per HPF).
