Dermoscopy, reflectance confocal microscopy, and high‐frequency ultrasound for the noninvasive diagnosis of morphea‐form basal cell carcinoma

Dear Editor,

A 59‐year‐old female presented with a 5‐year history of a solitary skin‐colored nodule on the upper lip (Figure 1A). The lesion gradually enlarged without any discomfort. No skin inflammation or trauma was observed at the same location. She was in good health and stated no prior medical history. Dermoscopy manifested arborizing vessels with whitish structures presented on the pink background (Figure 1B). Reflectance confocal microscopy (RCM) showed numbers of bright tumor islands with peripheral palisading, cleft‐like dark spaces, and dilated canalicular vessels in the dermis (Figure 1C). High‐frequency ultrasound (HFUS) revealed an irregular hypoechoic dermal and hypodermal structure (Figure 1D). Histopathology revealed strands and nests of basaloid cells surrounding dense and sclerotic fibrous stroma in the dermis and subcutaneous tissue (Figure 1E). A diagnosis of morphea‐form basal cell carcinoma (BCC) was made. The patient was successfully treated with surgery, and follow‐up for 2 years showed no recurrence.

FIGURE 1.

(A) A single skin‐colored nodule on the upper lip. (B) Dermoscopy: arborizing vessels with whitish structures on the pink background (×50 magnification). (C) RCM: bright tumor islands with peripheral palisading, cleft‐like dark spaces, and dilated canalicular vessels in the dermis (0.5 × 0.5 μm magnification). (D) Ultrasound: an irregular hypoechoic dermal and hypodermal structure (20 MHz) (E) Strands and nests of basaloid cells surrounding dense and sclerotic fibrous stroma in the dermis and subcutaneous tissue (HE ×100)

BCC is the most common cutaneous malignant neoplasm worldwide, and its incidence continues to increase. It is preferentially localized on photo‐exposed areas, particularly the face and the scalp. The most common subtype of BCC is nodular BCC, followed by superficial BCC. The more invasive and aggressive subtypes, such as metatypic, plexiform, and morphea‐form BCC, are rare and more challenging to diagnose on clinical grounds alone. As noninvasive and convenient imaging technologies, dermoscopy, RCM and HFUS are sensitive and specific tools for diagnosing BCC and can provide multimodal information for the management.

By visualizing cutaneous structures that are invisible to the naked eye, dermoscopy increases the accuracy of dermatologic examinations. The sensitivity and specificity of BCC diagnosis were significantly improved after adding dermoscopy to the naked‐eye examination. ¹ The sensitivity and specificity of dermoscopy for BCC diagnosis were 91.2% and 95%, respectively. ¹ Furthermore, the dermoscopic feature may aid in differentiating between BCC histopathologic subtypes. ² The main dermoscopic feature of morphea‐form BCC was pink‐white areas and/or fine arborizing vessels. ³ However, dermoscopy can only observe the epidermal and superficial dermal structures. For deeper structural detection, RCM and HFUS are more advantageous.

RCM can supply image information closed to histologic resolution. Previous studies assessing RCM for BCC diagnosis reported varying sensitivity and specificity values ranging from 85%–97% and 89%–99%, respectively. ⁴ Meanwhile, RCM and dermoscopy were helpful for preoperative defining lesional boundary and BCC histopathologic subtypes. ⁵ , ⁶ , ⁷ On RCM, cords connected to the epidermis were seen in superficial BCC; big tumor islands, peritumoral collagen bundles and increased vascularization were relative to nodular BCC; and hyporefractile silhouettes associated with aggressive BCC. ⁶ HFUS can provide reliable information about BCC, such as histopathological subtype differentiation, margin delineation, and tumor size assessment. ⁸ , ⁹ The recurrence risk of BCC can be assessed preliminary by quantifying the ultrasonographic examinations. ⁸ The presence of seven or more hyperechogenic spots within the lesion has been associated with histological subtypes with a high risk of recurrence. ¹⁰

A variety of imaging techniques with their own advantages can supply multimodal preoperative information for the management options that purpose to meet the needs of clinicians, except for improving the diagnostic accuracy of BCC.

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