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==Introduction==

==Introduction==

Canine cutaneous histiocytoma is a '''common, usually benign tumour of dogs'''. It is thought to be derived from epidermal '''Langerhans cells'''.

Canine cutaneous histiocytoma is a '''common, usually benign tumour of dogs'''. It is thought to be derived from epidermal '''Langerhans cells'''.

These tumours are seen mostly in '''younger dogs''', and the incidence drops drastically after 3 years of age. There are no apparent breed or sex predilections.  

These tumours are seen mostly in '''younger dogs''', and the incidence drops drastically after 3 years of age. There are no apparent breed or sex predilections.  

==Clinical signs==

==Clinical Signs==

Histiocytomas generally arise on the '''head, ears and limbs''' of dogs, and appear as rapidly-growing, '''erythematous, dome-shaped nodules less than 2.5cm in diameter'''. They are usually solitary, though multiple lesions can appear in a short period of time.

Histiocytomas generally arise on the '''head, ears and limbs''' of dogs, and appear as rapidly-growing, '''erythematous, dome-shaped nodules less than 2.5cm in diameter'''. They are usually solitary, though multiple lesions can appear in a short period of time.

'''Alopecia and ulceration''' are common.

'''Alopecia and ulceration''' are common.

'''Lymphadenopathy''' can occur due to migration of histiocytoma cells to the draining lymph nodes.

'''[[Lymphadenopathy]]''' can occur due to migration of histiocytoma cells to the draining lymph nodes.

==Diagnosis==

==Diagnosis==

A cytology sample should be taken by '''fine needle aspiration'''.

A cytology sample should be taken by '''fine needle aspiration'''. A cytological diagnosis is not always easy to make for these tumours, and they can be confused with granulomatous inflammation, [[Mast Cell Tumour|mast cell tumors]], plasmacytomas, and [[Lymphosarcoma|cutaneous lymphosarcomas]].  

 

A cytological diagnosis is not always easy to make for these tumours, and they can be confused with granulomatous inflammation, mast cell tumors, plasmacytomas, and cutaneous lymphosarcomas.  

On '''cytology''': the cells appear round, with moderate anisocytosis and anisokaryosis. Nucleoli may vary from inconspicuous to prominent.

On '''cytology''': the cells appear round, with moderate anisocytosis and anisokaryosis. Nucleoli may vary from inconspicuous to prominent.

'''Surgical excision''' can also be an option if the mass does not regress or it causes bleeding or discomfort to the animal.

'''Surgical excision''' can also be an option if the mass does not regress or it causes bleeding or discomfort to the animal.

==References==

==References==

Gross, T. (2005) '''Skin diseases of the dog and cat''' ''Wiley-Blackwell''

Gross, T. (2005) '''Skin diseases of the dog and cat''' ''Wiley-Blackwell''

[[Category:To Do - Review]]

 

 

 

[[Category:Neoplasia]]

[[Category:Dermatological Diseases - Dog]]

[[Category:Expert Review - Small Animal]]