Dermoscopy of crusted lesion: diagnostic challenge and choice of technique for the analysis^☆☆

Dear Editor,

A 52-year-old male patient, phototype IV, with significant photodamage complained of a painful chest lesion, with a progressive increase in the 6 previous months. During the physical examination, he had an erythematous plaque measuring 4 × 8 cm, with yellowish crusts and violaceous borders on the left anterosuperior thorax region (Fig. 1). Dermoscopy was inconclusive due to the presence of nonspecific yellowish crusts on the lesion (Fig. 2).

Figure 1
Desquamative plaque on the anterosuperior thorax.

Figure 2
Dermoscopy before removal of crusts.

After applying wet compresses with saline solution, the crusts were carefully removed. To avoid contact with the lesion surface, polarized light dermoscopy was performed, which demonstrated the presence of glomerular vessels, suggestive of Bowen's disease (BD) (Fig. 3).¹ In view of this picture, an excisional biopsy was performed. Histopathological examination confirmed the diagnosis of BD.

Figure 3
Dermoscopy after removal of crusts, displaying glomerular vessels.

Dermoscopy is important in the diagnosis of pigmented and non-pigmented lesions.¹ In non-pigmented lesions, the vascular pattern can lead to the diagnosis, but in the reported case, it was not possible to achieve the diagnosis due to the presence of crusts. The presence of yellowish crusts at dermoscopy has been previously described in 78.8% of 146 evaluated BD lesions, but it is not specific, and the presence of crusts alone is not a sufficient criterion for this diagnosis.^2,3 In crusted lesions, the removal of the crusts may allow the observation of other dermoscopic structures that can help achieve the diagnosis. The removal of crusts should be performed with caution to avoid damage to the epithelium because this maneuver can allow the observation of other dermoscopic structures that make the diagnosis possible.

• ☆☆
  Study conducted at the Department of Dermatology, Universidade Federal de São Paulo, São Paulo, SP, Brazil.
• Financial support
  None declared.

References

• ¹
  Braun RP, Rabinovitz HS, Oliviero M, Kopf AW, Saurat J-H. Dermoscopy of pigmented skin lesions. J Am Acad Dermatol. 2005;52:109-21.
• ²
  Yang Y, Lin J, Fang S, Han S, Song Z. What’s new in dermoscopy of Bowen’s disease: two new dermoscopic signs and its differential diagnosis. Int J Dermatol. 2017;56:1022-5.
• ³
  Shakya NM, LeAnder RW, Hinton KA, Stricklin SM, Rader RK, Hagerty J, et al. Discrimination of squamous cell carcinoma in situ from seborrheic keratosis by color analysis techniques requires information from scale, scale-crust and surrounding areas in dermoscopy images. Comput Biol Med. 2012;42:1165-9.

Publication Dates

• Publication in this collection
  26 July 2021
• Date of issue
  May-Jun 2021

History

• Received
  20 Nov 2019
• Accepted
  30 June 2020