Hodgkin's lymphoma is a primary malignant tumor of the lymph nodes, rarely affecting the extranodal lymphoid tissue. The diagnosis criteria are : tumor component (Reed-Sternberg cell - typical and variants) and a reactive component (normal mature lymphocytes, eosinophils, plasma cells, neutrophils, fibrosis and capillaries).
Histological classification of Hodgkin's lymphoma (according to lymph node architecture, ratio between tumor and non-tumor components, morphology of Reed-Sternberg cell and compositon of reactive infiltrate) :
- (Non-classical) Nodular lymphocyte predominant Hodgkin's lymphoma (5 %)
- Classical Hodgkin's lymphoma
- Nodular sclerosing (60 - 80 %)
- Lymphocyte-rich (5 %)
- Mixed cellularity (15 - 30 %)
- Lymphocyte depleted (< 1 %)
Variants of Reed-Sternberg cell (RSC) :
- Hodgkin's cell (atypical mononuclear Reed-Sternberg cell (RSC)
- Lacunar Reed-Sternberg cell (RSC)
- Pleomorphic Reed-Sternberg cell (RSC)
- Limfo-histiocytic ("pop-corn") variant
- "Mummy" Reed-Sternberg cell (RSC)
Hodgkin's lymphoma (H&E, ob.x20)
Typical Reed-Sternberg cell : size between 20 - 50 microns; abundant, amphofilic, finely granular/homogenous cytoplasm; two mirror-image nuclei ("owl eyes") each with an eosinophilic nucleolus and a thick nuclear membrane (chromatin is distributed on the inner surface of the nuclear membrane, generating a halo image around the nucleolus).
Sternberg-Reed cell (II)
Hodgkin's lymphoma. Variants of Reed-Sternberg cell (H&E, ob.x20) :
- Hodgkin's cell (atypical mononuclear Reed-Sternberg cell is a variant of Reed-Sternberg cell, which has the same characteristics, but is mononucleated
- Lacunar Reed-Sternberg cell is large, with a single hyperlobated nucleus, multiple, small nucleoli and eosinophilic cytoplasm which is retracted around the nucleus, creating an empty space ("lacunae")
- Pleomorphic Reed-Sternberg cell has multiple irregular nuclei
- "Pop-corn" Reed-Sternberg cell (lympho-histiocytic variant) is a small cell, with a very lobulated nucleus, small nucleoli.
- "Mummy" Reed-Sternberg cell has a compact nucleus, no nucleolus and basophilic cytoplasm