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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.

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]]