Trichoblastoma: is a clinical or dermoscopic diagnosis possible?

BACKGROUND: Trichoblastoma is a rare benign skin tumour that must be differentiated from basal cell carcinoma for its benign course and favourable outcome. OBJECTIVES: To describe clinical and dermoscopic features of solitary primitive trichoblastoma and to compare them with trichoblastic basal cell carcinoma (tBCC). METHODS: Digital dermoscopic images of 19 trichoblastoma and 19 tBCC were compared and reviewed by a dermatologist experienced in dermoscopy. RESULTS: The most striking dermoscopic difference between trichoblastoma and tBCC was the presence of blue-grey globules and blue-grey ovoid nests that were found to be more frequent but not exclusive of tBCC. Arborizing vessels were found both in trichoblastoma and tBCC, with a lower frequency in the latter. CONCLUSION: Histology remains the gold standard to differentiate trichoblastoma from tBCC.