Dermoscopy of apocrine hidrocystomas: a morphological study.

BACKGROUND: The dermoscopic morphology of apocrine hidrocystomas remains to be elucidated. OBJECTIVE: To evaluate the morphological findings of apocrine hidrocystomas under dermoscopic observation. METHODS: Dermoscopic examination of 22 cases of apocrine hidrocystomas was performed to evaluate specific dermoscopic criteria and patterns. RESULTS: The most frequently occurring dermoscopic features were found to be: (i) A translucent to opaque, homogeneous area which occupies the whole lesion in all apocrine hidrocystomas (100%). The colour of this homogeneous area was skin-colored in 31.8% of our cases; yellow, in 31.8% and blue, in 22.7% of apocrine hidrocystomas. (ii) Vascular structures were identified in 81.8% of our cases; arborizing vessels, in 68.2% and linear-irregular vessels in 9.1% of our cases; and (iii) Whitish structures were identified in 22.7% of the lesions. The results of our study reveal that the presence of a homogeneous area that occupies the whole lesion and arborizing vessels is the most common dermoscopic pattern in apocrine hidrocystomas (68.2%). CONCLUSION: Apocrine hidrocystomas, above all in its pigmented variant, may represent a dermoscopic pitfall, being difficult to differentiate clinically and dermoscopically from basal cell carcinomas.

Dermoscopic pattern of intermediate stage in seborrhoeic keratosis regressing to lichenoid keratosis: report of 24 cases.

BACKGROUND: Lichenoid keratosis (LK) is a well-described entity which has been proposed to represent an immunological or regressive response to pre-existing epidermal lesions such as solar lentigines or seborrhoeic keratoses. OBJECTIVES: To evaluate the dermoscopic criteria of a series of cases of LK with remaining areas of seborrhoeic keratosis which were both dermoscopically and histologically diagnosed. METHODS: Pigmented lesions with dermoscopic areas of seborrhoeic keratosis and LK in the same tumour were consecutively diagnosed and prospectively included in the study. All pigmented lesions were examined and registered using DermLite Foto equipment (3Gen, LLC, Dana Point, CA, U.S.A.), at 10-fold magnification, at the Dermatology Department of Hospital de Sant Pau i Santa Tecla (Tarragona, Spain), between 1 January 2003 and 31 December 2005. RESULTS: In total, 24 cases of lesions with dermoscopic areas of seborrhoeic keratosis and LK were collected. In four lesions (17%), the clinical differential diagnosis without dermoscopy included malignant melanoma and in seven lesions (29%), basal cell carcinoma. The diagnosis of LK was clinically considered without dermoscopy in only six cases (25%). A granular pattern was observed to be distributed throughout the LK areas of the lesions. This pattern consisted of the presence of brownish-grey, bluish-grey or whitish-grey coarse granules that formed, in 11 cases (46%), globules and/or short lines. In one lesion, located on the face, these short lines produced annular or rhomboid structures as seen in lentigo maligna melanoma. CONCLUSIONS: Dermoscopy is a useful tool which assists in the correct clinical recognition of LK, which may also potentially illuminate the pathogenesis of these tumours, showing the intermediate stage of regressing epidermal lesions in an LK.