Its sweat gland- or sebaceous-lines of differentiation have been also reported.

The cells in desmoplastic trichoepithelioma are suggested to be in close association with the basal cells in the outer root sheath.

Diagnosis of this lesion is important because it may be mistaken for microcystic adnexal carcinoma clinically and histologically.

This condition should not be diagnosed on shave, curettage or punch biopsies.

Deep biopsy is necessary to identify subcutaneous involvement.

Clinical presentation:  Presents as a solitary, small indurated often depressed plaque on the face.

Differential Diagnosis:

1. Syringoma - Usually periorbital and multiple lesions ; Narrow strands of tumour cells ; Horn cysts, foreign body granulomas or calcifications are rare.

2. Morpheic Basal Cell Carcinoma - Form clefts between the nests and the stroma ; Coexisting nodular basal cell carcinoma; Mitoses and apoptotic bodies are common;Foreign body granulomas and ruptured keratinous cysts are rare.

i) Differential expression of PHLDA1 (TDAG51) in basal cell carcinoma and trichoepithelioma.

ii) PHLDA1 (TDAG51) is a follicular stem cell marker and differentiates between morphoeic basal cell carcinoma and desmoplastic trichoepithelioma.

iii) Desmoplastic trichoepithelioma versus morphoeic basal cell carcinoma: a critical reappraisal of histomorphological and immunohistochemical criteria for differentiation.

3. Microcystic adnexal carcinoma  

4. Metastatic breast carcinoma