Tricholemmomas are neoplasms of older dogs (5 - 13 years) with characteristic upregulation of CD34 expression with some functionally similar conditions to the terminal hair follicles in the anagen phase. The cause of this neoplastic transformation is unknown, although in humans has an hereditary origin.
The Afghan Hound breed appears predisposed and these tumors appear commonly on the head and neck as firm, ovoid and lobulated masses without involvement of deeper subcutaneous tissue.
Diagnosis is based on histological examination of biopsied material, with histological features involving positive PAS staining of keratinocytes due to their glycogen content. These tumors are often surrounded by thickened basement membranes.
Treatment is usually curative with wide-margin excision.
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- Misago N et al (2011) CD34 expression in human hair follicles and tricholemmoma: a comprehensive study. J Cutan Pathol 38(8):609-615
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