Color Atlas of Hematology - Practical Microscopic and Clinical ...

182Cytology of Organ Biopsies and ExudatesNon-Hodgkin LymphomaSince the CBC is the first step in any lymph node diagnosis, lymph node biopsyis unnecessary in many cases of non-Hodgkin lymphoma (p. 70), becausethe most common form of this group of diseases, chronic lymphadenosis,can always be diagnosed on the basis of the leukemic findings of theCBC.However, when enlarged lymph nodes are found in one or more regionswithout symptoms of reactive disease, and the blood analysis fails to showsigns of leukemia, lymph node biopsy is indicated.The relatively monotonous lymph node cytology in non-Hodgkin lymphomasand tumor metastases mean that histological differentiation isrequired.In contrast to Hodgkin disease, with its conspicuous giant cell forms(p. 177), non-Hodgkin lymphomas display a monotonous picture withoutany signs of a reactive process (p. 70). Clinically, it is enough to distinguishbetween small cell forms (which have a relatively good prognosis) andlarge cell forms (which have a poorer prognosis) to begin with. For a moredetailed classification, see page 70 f.Histological analysis may be omitted only when its final results wouldnot be expected to add to the intermediate cytological findings in terms ofconsequences for treatment.Metastases of Solid Tumors in Lymph Nodes orSubcutaneous TissueWhen hard nodules are found that are circumscribed in location, biopsyshows aggregates of polymorphous cells with mostly undifferentiated nucleiand a coarse reticular structure of the chromatin (perhaps with welldefinednucleoli or nuclear vacuoles), and the lymphatic cells cannot beclassified, there is urgent suspicion of metastasis from a malignant solidtumor, i.e. from a carcinoma in a variety of possible locations or a softtissue sarcoma.As a rule, the next step is the search for a possible primary tumor. If this isfound, lymph node resection becomes unnecessary.If no primary tumor is found, lymph node histology is indicated. The histologicalfindings can provide certain clues about the etiology and also helpsin the difficult differential diagnosis versus blastic non-Hodgkin lymphoma.