Follicular Lymphoma

Morphological features:

• Small, mature, atypical lymphoid cells (almost the same size as surrounding RBCs)
• Lymphocytosis may be minimal or marked
• Size ranges from smaller than CLL to larger with less condensed cytoplasm
• Characteristically have deep, narrow clefts; edges may be parallel
• Scanty, basophillic cytoplasm
• Smudge cells are not a feature, in contrast to CLL

Other features to look out for:

• Anaemia, especially spherocytes to suggest concurrent AIHA
• Thrombocytopaenia

Patterns of infiltration on trephine biopsy:

• Paratrabecullar (first slide)
• Nodular (second slide, also has some paratrabecullar infiltrate)
• Diffuse (last two slides)

Differential diagnosis:

• Chronic lymphocytic leukaemia
• Mantle cell lymphoma

Investigations:

• Immunophenotyping: CD5-/10+