Dermoscopy Clues in Pigmented Bowen's Disease

Abstract

Pigmented tumors have similar clinical features that overlap and hamper diagnosis. Dermoscopy increases the diagnostic accuracy of doubtful melanocytic lesions and has been used as a noninvasive tool in the detection of pigmented lesions (PLs) like melanoma, basal cell carcinoma, and pigmented Bowen's disease (pBD). Our objective was to show the dermoscopic features of 2 cases of pBD and compare with the findings reported in the literature. Two dermoscopic images of biopsy proven pBD were retrospectively analyzed for dermoscopic patterns. Both cases showed brown regular globules, structureless brown and blue pigmentation, glomerular vessels, hypopigmented regression-like areas, and keratosis. These findings were similar to the cases reported previously. The dermoscopic diagnosis of pBD is based on the absence of criteria for a melanocytic lesion in the presence of glomerular vessels, regular brown globules and keratosis. Although pBD is rare, it should be included in the differential diagnosis of PLs, especially melanoma.

Figure 1

Case 1. Pigmented lesion on the anterior aspect of the forearm.

Figure 2

Case 1. H&E shows pBD with parakeratosis and marked acanthosis consisting in atypical keratinocytes on all levels of the epidermis, dilated capillary vessels, and grouped melanophages only in the papillary dermis.

Figure 3

Case 2. Pigmented lesion on the left buttock and intergluteal fold.

Figure 4

Case 2. H&E shows pBD with marked hyperkeratosis, parakeratosis and acanthosis consisting of atypical keratinocytes on all levels of the epidermis. Dilated capillary vessels and grouped melanophages can be seen in the papillary dermis.

Figure 5

Dermoscopy in Case 1 shows central structureless brown and blue-gray pigmentation with keratosis, irregular peripheral pigmented streaks and brown regular globules in a linear arrangement. On the lower two thirds, light brown regular globules in linear and clustered arrangement, patches of clustered glomerular vessels, and a structureless hypopigmented central area.

Figure 6

Case 1. Closeup view of upper third of the lesion with peripheral streaks, central brown and blue-gray pigmentation with keratosis and brown globules in a linear arrangement.

Figure 7

Case 1. Closeup view of lower third of the lesion with patches of pigment globules and glomerular vessels in clustered and linear arrangement.

Figure 8

Dermoscopy in Case 2 shows structureless brown and blue-gray peripheral pigmentation with keratosis, patches of brown regular globules in clustered a linear arrangement, clusters of glomerular vessels in a linear arrangement, keratin globules (“cotton candy” keratosis) scattered throughout the lesion, as well as a linear keratinous rim.

Figure 9

Case 2. Closeup view of clusters of regular pigment globules and glomerular vessels in a linear arrangement. Central area shows brown and blue-gray structureless areas and keratosis.

Figure 10

Case 2. Closeup view of “cotton candy” keratosis, keratinous rim and peripheral brown globules in linear arrangement.

Figure 11

Case 1. Fontana Masson stain highlights pigment in corneocytes, dendritic melanocytes, dermal melanophages, and scarcely in keratinocytes.

Figure 12

Case 1. Fontana Masson highlights pigment in dendritic melanocytes (a) correlating with pigmented peripheral streaks (b). The scarce pigment in keratinocytes correlates with a structureless brown pattern and the melanophages with the blue-gray areas and clusters of brown globules (bottom b).

Figure 13

Case 2. Fontana Masson stain highlights melanin pigment in dendritic melanocytes and dermal melanophages, but not in keratinocytes.

Figure 14

Case 2. H&E. Melanophages arranged in groups in the papillary dermis that correlate with brown globules and dilated capillary vessels correlate with glomerular vessels.

Figure 15

Case 2. H&E. Closeup of dilated capillary vessels in the papillary dermis enclosed by the marked acanthosis that correlates with glomerular vessels.

Figure 16

Case 2. Marked hyperkeratosis and parakeratosis correlates with “cotton candy” pattern keratosis.