In Vivo Reflectance Confocal Microscopy of Adnexal Tumors: Evaluation of Trichoepithelioma, Sebaceoma, and Fibrofolliculoma

Sebaceoma on the nose mimicking basal cell carcinoma: Pitfalls of dermoscopy and reflectance confocal microscopy

Sebaceoma is a rare benign sebaceous tumor that usually occurs on the face and scalp. We report a case of a 3-mm solitary pink papule on the nose in an elderly woman. Dermoscopic examination showed yellow-pinkish background with a central yellow homogeneous structure, peripheral branching vessels (crown vessels), and scattered gray or reddish-brown irregular areas. Reflectance confocal microscopy (RCM) revealed tumor islands with massive dendritic cells and scattered bright fine granules in the dermis, a suspicious palisading arrangement at the periphery, and there seemed to be peritumoral dark spaces. The combined dermoscopic and RCM examination were highly suspicious for the diagnosis of basal cell carcinoma (BCC), so the lesion was excised completely, but was eventually diagnosed as sebaceoma by histopathology. This case suggests that there are some overlaps in both dermoscopic and RCM features between sebaceoma and BCC. The application of dermoscopy and RCM to the diagnosis of sebaceoma is challenging, further studies are needed in this field.

Significance of Dermoscopy in Association with Clinical Features in Differentiation of Basal Cell Carcinoma and Benign Trichoblastic Tumours

Background: Although basal cell carcinoma (BCC) can, in the majority of cases, be diagnosed based on clinical and dermoscopic assessment, a potential overlap with benign adnexal skin tumours seems to exist, including trichoblastic tumours (TT). Methods: Retrospective analysis of clinical and dermoscopic features of benign TT and BCC cases was performed to develop a diagnostic algorithm with a potential utility in clinical practice. Results: In the study, 502 histopathologically confirmed BCC cases were compared with 61 TT (including 44 TB (72.13%), 10 TE (16.39%) and 7 DTE (11.48%]). Patients in the BCC group were statistically older (mean age was 71.4 vs. 64.4 years, respectively; p = 0.009). BCC presented generally as larger tumours (mean tumour size 11.0 vs. 8.2 mm for the TT group; p = 0.001) and was more frequently associated with clinically visible ulceration (59.4% vs. 19.7%, respectively; p < 0.001). Comparison of lesion morphology, clinically visible pigmentation, and anatomical location did not show significant differences between the analysed groups. Dermoscopically visible ulceration was significantly more common in the BCC group compared to the TT group (52.2% vs. 14.8%; p < 0.0001). Pigmented structures, specifically brown dots and brown globules, were significantly more prevalent in the TT group (32.8% vs. 11.4%; p = 0.0001 and 29.5% vs. 8.2%; p <0.0001). Similarly, TT more commonly than BCC showed the presence of cloudy/starry milia-like cysts (26.2% vs. 11.6%; p = 0.0031) and yellow globules (16.4% vs. 7.2%; p = 0.033). Conclusions: Despite differences in frequency of clinical and dermoscopic features between BCC and TT in the studied group, differential diagnosis based on these variables is not reliable. Histopathological examination remains a diagnostic gold standard in differentiation of BCC and TT.