TABLE 3.
SEBORRHEIC KERATOSIS, SOLAR LENTIGO AND LICHEN PLANUS-LIKE KERATOSIS: RCM TERMS, FREQUENCY OF LITERATURE USE, SUGGESTED GROUPING BASED ON SIMILARITY IN DEFINITIONS AND HISTOPTAHOLOGICAL CORRELATES
| RCM Terms | Frequency of use of an individual RCM term | Definition | Histopathological correlates |
|---|---|---|---|
| SUPRABASAL EPIDERMIS TERMS (N=9; 39.1%) | |||
| Milia-like cysts31 | 1 | Homogeneous and bright areas without sharply demarcated borders surrounded by a dark halo within the epidermis | Intraepidermal keratin cysts |
| Corneal pseudo cysts10,39,41 | 3 | ||
| Subtotal (weight*) | 4 (12.1%) | ||
| Keratin-filled invaginations10,41 | 2 | Round to longitudinal invaginations of the lesion surface, harboring structureless amorphous material of variable brightness on RCM | Keratin-filled papillomatous epidermis |
| Surface holes and fissures39 | 1 | ||
| Subtotal (weight*) | 3 (9.1%) | ||
| Cerebriform appearance38 | 1 | Round to linear structures, darker than the surrounding epidermis, resembling the surface of a brain (gyri and sulci) | Papillomatous epidermis |
| Subtotal (weight*) | 1 (3.03%) | ||
| Typical honeycomb pattern39 | 1 | Honeycomb pattern with regular thickness of lines and sizes of holes | Regular epidermis |
| Regular honeycomb pattern10,41,42 | 3 | ||
| Subtotal (weight*) | 4 (12.1%) | ||
| Epidermal projections10,41 | 2 | Projections of the epidermal surface of the lesion | Projections of rete ridges |
| Subtotal (weight*) | 2 (6.1%) | ||
| Small bright homogeneous cells31** | 1 | Small bright homogeneous cells present on basal layers, corresponding to pigmented keratinocytes | Pigmented keratinocytes in the basal layer |
| Subtotal (weight*) | 1 (3.03%) | ||
| Total for Suprabasal Epidermis (weight) | 15 (45.4%) | ||
| BASAL LAYER/DEJ/SUPERFICIAL DERMIS TERMS (N=14; 60.8%) | |||
| Polycyclic shapes of dermal papillae38 | 1 | At the DEJ level, densely packed round to polymorphous dermal papillae, usually with pigmented keratinocytes. | Elongated and bridging rete ridges with pigmented keratinocytes |
| Densely packed round to polymorphous dermal papillae10 | 1 | ||
| Packed dermal papillae41 | 1 | ||
| Polycyclic papillary contours40 | 1 | ||
| Subtotal (weight*) | 4 (12.1%) | ||
| Edged papillae42 | 1 | Dark round to oval structures surrounded by a rim of bright monomorphic cells | Pigmented keratinocytes at the DEJ |
| Subtotal (weight*) | 1 (3.03%) | ||
| Cords*** and bulbous projections10,41 | 2 | Elongated bright tubular structures (cords***) with bulbous projections at the DEJ | Elongated and bridging rete ridges with pigmented keratinocytes |
| Cord-like*** rete ridges42 | 1 | ||
| Elongated cords39*** | 1 | ||
| Anastomosing epithelial cords31*** | 1 | ||
| Bulbous projections39 | 1 | ||
| Subtotal (weight*) | 7 (21.2%) | ||
| Mixed vascular pattern10,41 | 2 | A prominent vascular pattern with dilated round and linear blood vessels (running perpendicular and parallel, respectively) | Neovascularization |
| Subtotal (weight*) | 2 (6.1%) | ||
| Plump bright cells10,31,39† | 3 | Irregularly shaped bright cells with ill-defined borders and no visible nucleus, corresponding to melanophages | Melanophages in the dermis |
| Melanophages10† | 1 | ||
| Subtotal (weight*) | 4 (12.1%) | ||
| Bright stellate spots39†† | 1 | Small bright round structures (<20 um) without visible nucleus corresponding to leukocytes | Inflammatory cells: lymphocytes and neutrophils |
| Subtotal (weight*) | 1 (3.03%) | ||
| Total for basal layer/DEJ/superficial dermis | 18 (54.5%) | ||
| TOTAL TERMS FOR SL/SK/LPLK (N=23; 100%) | 33 (100%) | ||
Superscripted numbers refer to the publication.
Weight calculates the relative frequency of use for each subgroup of terms; the denominator is the total times SL/SK/LPLK terms were used in the literature (n=30).
Despite not defined for this group of lesions, we recommend using the standard term “cobblestone pattern” to avoid confusion.
We do not recommend using the term ‘cords’ to avoid confusion with ‘cord-like’ structures of Basal cell carcinoma.
These criteria have been associated mostly to lichen planus-like keratosis.
The term “Inflammatory infiltrate” was not used in the literature in reference to SL/SK/LPLK; for consistency with the literature, we recommend using “bright stellate spots”.