Histopathology of haematolymphoid

Haematolymphoid pathology is one of the most diverse and challenging area of diagnostic pathology by virtue of the immense diversity and complexity of immune system itself. Precise categorization of haematolymphoid neoplasms also invariably require immunophenotyping by ‘immunohistochemistry (IHC)’ or/and ‘flow cytometry’ in addition to molecular genetic testing by FISH or PCR. Common biopsy sites include ‘lymph node’ from all regions, extra-nodal sites in particular from GIT, though no site is exempt as well as ‘bone trephine’. In this chapter both non-neoplastic and neoplastic lesions are covered, though major focus is on salient microscopic features both at architectural and cellular level along with judicious use of IHC and other ancillary testing of haematolymphoid neoplasms to differentiate these from close mimicries on one hand and from atypical reactive patterns on the other.