TABLE 1.
BASAL CELL CARCINOMA: 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=13; 22.4%) | |||
| Actinic changes in honeycomb7,8,19* | 3 | Keratinocytic atypia with varying size of nuclei, pleomorphism, architectural disarray, parakeratotic nuclei | Keratinocytic atypia within the epidermis |
| Architectural disorder of overlying epidermis18 | 1 | ||
| Mild keratinocyte atypia21 | 1 | ||
| Atypical honeycomb pattern6 | 0 | ||
| Subtotal (weight**) | 5 (4.7%) | ||
| Elongated nuclei in the epidermis7,8,19 | 3 | Elongated monomorphic basaloid nuclei both in the epidermis aligned in the same axis and underlying tumor nests | No known histopathologic correlate. Probably the en face view of the uppermost part of a tumor nest or cord with palisading |
| Streaming of the epidermis21–26 | 6 | ||
| Polarization19, 27 | 2 | ||
| Polarized in the honeycomb6 | 1 | ||
| Polarization of nuclei of the epidermis7,8,19 | 3 | ||
| Subtotal (weight) | 15 (14.2%) | ||
| Prominent nucleoli7 | 1 | Visible nucleoli inside the nucleus of a BCC elongated cell | Prominent nucleoli in the nucleus of keratinocytes |
| Subtotal (weight) | 1 (0.9%) | ||
| Epidermal shadow6,27 | 2 | Large featureless area with blurred border disrupting the normal epidermis and corresponding to the horizontal clefting | Not known, probably an optical effect of the en face view of a tumor nest |
| Subtotal (weight) | 2 (1.9%) | ||
| Ulceration23,26 | 2 | Disruption in the bright skin surface and in the underlying layers of the epidermis, seen as a dark area with or without bright amorphous or fibrillar debris12 | Ulceration of the epidermis |
| Subtotal (weight) | 2 (1.9%) | ||
| Onion-like structures23,26 | 2 | Round black spaces centered by brightly refractile material, corresponding to milia-like cysts | Epidermal cysts |
| Subtotal (weight) | 2 (1.9%) | ||
| Total for Suprabasal Epidermis (weight) | 27 (25.7%) | ||
| BASAL LAYER/DEJ/SUPERFICIAL DERMIS TERMS (N=45; 77.6%) | |||
| Pigmented nests of basal cells16 | 1 | Highly packed cells corresponding to islands of basaloid tumor cells with high refractivity | Nests of basaloid cells in the DEJ or superficial dermis. Mostly associated to the nodular subtype |
| Tumor nodules18,19 | 2 | ||
| Nests of basaloid cells21 | 1 | ||
| Tumor island22,25,26 | 3 | ||
| Bright tumor islands24 | 1 | ||
| ∘ Small tumor islands23 | 1 | Tumor islands <300 um diameter | |
| ∘ Big tumor islands23 | 1 | Tumor islands >300 um diameter | |
| Subtotal (weight) | 10 (9.5%) | ||
| Basaloid cells17 | 1 | Cells with elongated nuclei and a palisading in the periphery of the tumor parenchyma | Organization of the basaloid cells at the periphery of the tumor nests |
| Palisading18,22 | 2 | ||
| Peripheral palisading21,23–26 | 5 | ||
| Subtotal (weight) | 8 (7.6%) | ||
| Peritumoral dark space18 | 1 | Cleft-like hyporeflective spaces surrounding tumor nests | Clear spaces between the tumor parenchyma and the surrounding stroma. Most probably correspond to mucin. |
| Cleft-like spaces20 | 1 | ||
| Clefting6,23,27 | 3 | ||
| Clefts44 | 1 | ||
| Peripheral clefting26 | 1 | ||
| Dark peritumoral cleft24,25 | 2 | ||
| Subtotal (weight) | 9 (8.6%) | ||
| Cord-like structures18,26 | 2 | Tightly packed tumor cells forming trabeculae | Nests of basaloid cells connected to the DEJ. Highly associated to the superficial subtype |
| Basaloid cords and nodules6,27 | 2 | ||
| Cord23 | 1 | ||
| Subtotal (weight) | 5 (4.7%) | ||
| Dendritic structures19 | 1 | Bright thin or coarse dendritic-like structures within tumor islands frequently associated to a clearly visible nucleated cell | When within the tumor nest, mostly they correspond to melanocytes (Melan-A stain) and few are Langerhans cell (CD 1a) |
| Dendritic-like features6 | 1 | ||
| Nucleated cell within tumor island6 | 1 | ||
| Bright dendritic structures19,24 | 1 | ||
| Dendritic cells26*** | 1 | ||
| Bright round cells24 | 1 | ||
| Subtotal (weight) | 6 (5.7%) | ||
| Dark silhouettes22–26 | 5 | Low reflectance tumor islands / Longo:23 Hyporeflective areas outlined by bright collagen bundles in the surrounding dermis that correspond to basaloid islands | Nests of basaloid cells in the superficial dermis or deeper, not visible due to the lack of resolution after 150 – 200 μm. Associated to the infiltrative subtype |
| Dark nodules26,27*** | 1 | ||
| Subtotal (weight) | 6 (5.7%) | ||
| Solar elastosis21 | 2 | Peppelman et al:21 bright irregular bundles and lacelike structures | Degeneration of the elastic fibers of the chronically sun-exposed skin |
| Subtotal (weight) | 2 (1.9%) | ||
| Melanophages16,18 | 2 | Irregularly shaped bright cells with ill-defined borders and usually no visible nucleus distributed within and outside tumor islands | Melanin-laded macrophages in the superficial dermis |
| Plump bright cells19,21,22 | 3 | ||
| Subtotal (weight) | 5 (4.7%) | ||
| Collagen bundles17 | 1 | Increased number of fibers bundles orientated parallel, surrounding tumor | Collagen reaction to the tumor in the surrounding stroma |
| Fibrosis surrounding tumor nests21 | 1 | ||
| Stromal reaction26*** | 1 | ||
| Thickened collagen bundles24,25 | 2 | ||
| Subtotal (weight) | 5 (4.7%) | ||
| Increased vascularity7,8,18,19,21–23,26 | 8 | Increased number of dilated (10 – 105 μm) blood vessels with occasional rolling of leukocytes (starting at 35 – 50 μm below epidermal surface); these vessels are often horizontal (parallel) | Dilated blood vessels running parallel to the epidermal surface |
| Enlarged blood vessels17 | 1 | ||
| Prominent vasculature19 | 1 | ||
| Linear telangiectasia-like horizontal vessels6 | 1 | ||
| Linear or convoluted dilated blood vessels25,26 | 2 | ||
| Linear blood vessels24 | 1 | ||
| Subtotal (weight) | 14 (13.3%) | ||
| Fibrillar polarized pattern around tumor6 | 1 | Fibrillary polarized features drawing a reticulation pattern around tumor island | N/A |
| Subtotal (weight) | 1 (0.9%) | ||
| Inflammatory infiltrate | 1 | Bright, highly refractile round or scattered cells representing leukocytes and neutrophils, respectively | Infiltrate of lymphocytes and leukocytes in the tumor parenchyma and stroma |
| Prominent inflammatory infiltrate7, 8, 19 | 3 | ||
| Inflammatory particles26 | 1 | ||
| Inflammation23 | 1 | ||
| Subtotal (weight) | 6 (5.7%) | ||
| Total for basal layer/DEJ/superficial dermis (weight) | 78 (74.2%) | ||
| TOTAL TERMS FOR BCC (N=58; 100%) | 105 (100%) | ||
*
Superscripted numbers denote reference numbers.
**
Weight calculates the relative frequency of use for each subgroup of terms; the denominator is the total times BCC terms were used in the literature (n=78).
***
These terms had no definition in the cited articles and thus grouping under each likely-synonymous term was done by the authors of this paper.