An 87-year-old woman presented for a 12-month follow-up examination after radiation therapy for management of a 20 × 25-mm lentigo maligna on her left cheek (Fig 1, A).
Dermoscopy demonstrated asymmetric structureless light-brown pigmentation with scattered brown dots, angulated pigmented lines, focal fine-pigmented semicircles, and areas of a dense vascular network (Fig 1, B).
Lesion assessment with handheld reflectance confocal microscopy (Vivascope 3000, Caliber ID, Rochester, NY) demonstrated diffuse epidermal disarray with intermittent areas of pagetoid dendritic cells with small dendrites, along with a singular focus of folliculotropic pagetoid dendritic cells with large dendrites, at the dermoepidermal junction (Fig 2, A).
A precise biopsy was performed after reflectance confocal microscopy identification of a singular focus of perifollicular dendritic cells. A 3-mm biopsy punch was used to perforate a round window in hypoallergenic adhesive paper tape (Micropore, 3M, St. Paul, MN), which was then adhered over the area of concern within the lesion (Fig 3, A and B). Further assessment with the handheld reflectance confocal microscopy tool was performed through the perforation, with subsequent repositioning of the tape until the area of perifollicular dendritic cells was identified within the window (Fig 2, B). The tape was left in situ and a 3-mm punch biopsy was performed through the perforation.
Histopathology initially demonstrated basal keratinocyte pigmentation and a mild increase of junctional melanocytes, and lacked any significant radiation-induced fibrosis after initial bread-loaf sectioning. Diagnostic features of melanoma were not identified. The presence of folliculotropic dendritic cells at the margins of the biopsy site as noted on reflectance confocal microscopy was subsequently communicated to the histopathologist. Further biopsy sectioning showed confluent lentiginous proliferation of atypical melanocytes at the dermoepidermal junction and involved a hair follicle, consistent with lentigo maligna on hematoxylin-eosin staining, within 0.5 mm of the specimen edge (Fig 4, A and B). Additional Sox10 staining was not possible, given the absence of tissue after final sectioning to identify the tiny focus of residual lentigo maligna.
The application and benefit of reflectance confocal microscopy as an aid for diagnosis in the management of lentigo maligna have been well established.1 Because lentigo maligna commonly presents as large lesions on the head and neck, use of the handheld Vivascope 3000 is often required to perform complete lesional assessment, along with margin delineation to identify subclinical spread.2,3 Although the Vivascope 3000 allows rapid en face evaluation of larger lesions, in situ correlation of identified areas of concern with the handheld device remains a challenge. Techniques previously reported to address this difficulty include the use of a 10-mm adhesive paper ring placed around lesions of concern, or, for larger lesions, demarcation with medical tape.4,5 Adhesive tape fibers produce a characteristic patterning when viewed with reflectance confocal microscopy, which allows easy delineation from background skin (Fig 2, B).
By using the technique detailed above, we build on previously reported applications of adhesive tape to guide reflectance confocal microscopy and, to our knowledge, are the first to describe this precise reflectance confocal microscopy biopsy technique. With this technique, biopsies can be made with greater certainty that concerning features of malignancy on reflectance confocal microscopy are appropriately targeted within millimeters, and it allows precise confocal imaging information to be relayed to histopathologists to help guide their assessment. This case highlights the challenges lentigo maligna presents for clinicopathologic correlation and demonstrates how the use of the described refined reflectance confocal microscopy–guided biopsy technique can aid in obtaining accurate diagnosis to improve patient outcomes.