Changes

Cytology is a necessary tool in the work-up of a lymphoma case. It provides both a '''diagnosis''' and a '''prognosis''' when combined with the '''entire clinical picture'''. Lymphoma produces a cell  

Cytology is a necessary tool in the work-up of a lymphoma case. It provides both a '''diagnosis''' and a '''prognosis''' when combined with the '''entire clinical picture'''. Lymphoma produces a cell  

population which is both distinct and recognisable, allowing identification and classification of the type of lymphoma by cytology. '''Fine needle aspiration''' is a '''quick''', '''cheap''',  

population which is both distinct and recognisable, allowing identification and classification of the type of lymphoma by cytology. '''Fine needle aspiration''' is a '''quick''', '''cheap''',  

'''non-invasive''' and '''effective''' method for collecting cells for cytology, and should always be considered a '''first-line test'''. Ideally cytology should always be supported by histology.  

'''non-invasive''' and '''effective''' method for collecting cells for cytology, and should always be considered a '''first-line test'''. Ideally cytology should always be supported by histology for immunophenotyping to distinguish B and T cell forms. Hyperplastic or reactive lymph nodes can be difficult to interpret and a second opinion from a qualified cytologist should always be taken when available prior to commencing treatment.  

Cytology can also be used to examine pleural fluid samples if there is a suspicion of neoplasia.

Cytology can also be used to examine pleural fluid samples if there is a suspicion of neoplasia.

* '''Coarse chromatin'''

* '''Coarse chromatin'''

These features can be assessed to determine the '''grade''' of tumour and therefore the likely '''treatment response''' and '''progression of disease'''. Small well-differentiated lymphocytes normally suggest a low-grade lymphoma, and large, poorly differentiated lymphoid cells suggest a higher grade of lymphoma.

These features can be assessed to determine the '''grade''' of tumour and therefore the likely '''treatment response''' and '''progression of disease''' though the prognostic ability of cytology remains poor. Small well-differentiated lymphocytes normally suggest a low-grade lymphoma, and large, poorly differentiated lymphoid cells suggest a higher grade of lymphoma and with that a poorer prognosis.

'''Dogs'''

'''Dogs'''

:Canine lymphoma is normally '''multicentric''', therefore the ideal method for collecting a sample for cytological examination is '''fine needle aspiration of the lymph nodes'''. Ideally samples should come from '''multiple nodes''' to give a representative sample. '''Popliteal''' and '''prescapular lymph nodes''' are easily accessible and therefore ideal for sampling. Submandibular lymph nodes should be avoided where possible as they are commonly enlarged and reactive as a result of dental disease. It should be noted that canine lymphoma can occur in any organ containing lymphoid tissue.

:Canine lymphoma is most commonly'''multicentric''', therefore the ideal method for collecting a sample for cytological examination is '''fine needle aspiration of the lymph nodes'''. Ideally samples should come from '''multiple nodes''' to give a representative sample. '''Popliteal''' and '''prescapular lymph nodes''' are easily accessible and therefore ideal for sampling. Submandibular lymph nodes should be avoided where possible as they are commonly enlarged and reactive as a result of dental disease. It should be noted that canine lymphoma can occur in any organ containing lymphoid tissue.

'''Cats'''

'''Cats'''

:Feline lymphoma is more '''variable''' in its presentation, with the three types  ('''mediastinal''', '''alimentary''' and '''multicentric''') common in general practice. The sample taken for cytological examination should be appropriate for the type of lymphoma:

:Feline lymphoma is more '''variable''' in its presentation, with extra-nodal forms being the commonest in general practice in the UK. The sample taken for cytological examination should be appropriate for the type of lymphoma:

::'''Ultrasound guided aspirates''', '''partial thickness endoscopic grab biopsies''' or '''full thickness biopsies''' via '''exploratory laparotomy''' for intenstinal lymphoma

::'''Ultrasound guided aspirates''', '''partial thickness endoscopic grab biopsies''' or '''full thickness biopsies''' via '''exploratory laparotomy''' for intestinal lymphoma

::'''Pleural fluid aspirate''' with or without supporting '''ultrasounded-guided aspirate or core biopsy''' of the mass (which will differentiate it from thymoma) with mediastinal lymphoma

::'''Pleural fluid aspirate''' with or without supporting '''ultrasound-guided aspirate or core biopsy''' of a mediastinal mass (which will in most cases differentiate it from thymoma though for some flow cytometry is necessary to make this distinction)  

::'''Peripheral lymph node aspirates''' for multicentric lymphoma

::'''Peripheral lymph node aspirates''' for multicentric lymphoma

:Lymphoma can occur in any tissue containing lymphoid tissue, for example the '''eye''', '''kidney''', '''CNS''', '''liver''', '''upper respiratory tract''', '''lungs''' and '''skin'''. Cytology is an essential tool for diagnosis in these cases, as the lymphoma can present with variable clinical signs and diagnosis can only be confirmed using cytology. As mentioned above, the cytological diagnosis should be supported by histopathology if possible, particularly if the cytological sample is equivocal.

:Lymphoma can occur in any tissue containing lymphoid tissue, for example the '''eye''', '''kidney''', '''CNS''', '''liver''', '''upper respiratory tract''', '''lungs''' and '''skin'''. Cytology is an essential tool for diagnosis in these cases, as the lymphoma can present with variable clinical signs and diagnosis can only be confirmed using cytology. As mentioned above, the cytological diagnosis should be supported by histopathology if possible, particularly if the cytological result is equivocal.

:'''NB'''. Lymphoma should not be confused with [[Lymph Node Abnormalities#Reactive Lymph Nodes|

:'''NB'''. Lymphoma should not be confused with [[Lymph Node Abnormalities#Reactive Lymph Nodes|

reactive lymphoid hyperplasia]] in the healthy cat. Generalised lymphadenopathy may present like multicentric lymphoma but is infact a natural immune response in the healthy cat. The same should be considered in other types of lymphoma, for example hepatic lymphoma looks cytologically identical to lymphocytic periportal hepatitis, and it is necessary to incorporate the entire clinical picture when making a diagnosis. Histopathological sampling is ideal for confirming the diagnosis.

reactive lymphoid hyperplasia]] in the healthy cat. Generalised lymphadenopathy may present like multicentric lymphoma but is in fact a natural immune response in the healthy cat. The same should be considered in other types of lymphoma, for example hepatic lymphoma looks cytologically very similar to lymphocytic periportal hepatitis, and it is necessary to incorporate the entire clinical picture when making a diagnosis. Histopathological sampling is ideal for confirming the diagnosis.

'''Horse'''

'''Horse'''