Investigations
1st investigations to order
biopsy for dermatohistopathology
Test
The diagnosis of a cancer is histological; it is advisable to perform either a shave biopsy or punch biopsy.[44][47] Deep reticular dermis should be included in the biopsy to avoid missing an infiltrative histology, which may sometimes be present only at the deeper, advancing margins of a tumour.[44]
Punch biopsy is best used in cosmetically non-challenging areas. An advantage of punch biopsy is that the tools may be available in sizes of up to 12 mm. Accordingly, lesions smaller than this can be removed in a single procedure, facilitating simultaneous diagnosis and treatment.[48]
Reserve shave biopsy for cosmetically challenging areas such as the face.
Result
growth of nest(s) of varying size and shape, either tightly associated with epidermis or follicular opening; neoplasm composed of basophilic (blue) hyperchromatic cells, with high nuclear-cytoplasmic ratio, and so-called peripheral palisading (on the edges of the neoplastic nests, nuclei of malignant cells are arranged in a manner similar to a picket fence); stroma surrounding BCC is hypercellular, fibrous; commonly, there is a separation (retraction) artefact between nests of neoplastic cells and the stroma (so-called stroma-epithelium split); additionally, in conjunction with the stroma, pools of blue dermal mucin (increase in dermal glycosaminoglycans) are identified
Investigations to consider
MRI scan
Test
Consider for patients with high-risk basal cell carcinoma (BCC) if clinical examination is insufficient for determining disease extent and for patients with locally advanced disease.[44]
Imaging studies are also indicated in rare instances where patients present with metastatic BCC.[44]
Choice of imaging modality and targeted area depends on the suspected extent of disease after multidisciplinary discussion.[44][45] MRI may be preferred for suspected perineural invasion or to gauge the extent of local disease.[44]
Result
may show local invasion or metastasis
CT scan
Test
Consider for patients with high-risk basal cell carcinoma (BCC) if clinical examination is insufficient for determining disease extent and for patients with locally advanced disease.[44]
Imaging studies are also indicated in rare instances where patients present with metastatic BCC.[44]
Choice of imaging modality and targeted area depends on the suspected extent of disease after multidisciplinary discussion.[44][45] CT may be preferred for suspected bone involvement or to confirm and gauge the extent of nodal or distant metastasis.[44]
Result
may show local invasion or metastasis
Emerging tests
in vivo multiphoton microscopy
Test
Uses non-invasive, label-free in vivo imaging to reveal several characteristic features of basal cell carcinoma lesions that may help facilitate diagnosis.[49] Reflectance confocal microscopic technologies have become a popular method for non-invasive approaches to aid in the diagnosis of basal cell carcinomas.[45][50][51] Adding artificial intelligence to non-invasive imaging has tremendous potential and is the subject of active investigation.[50] However, further research is needed to isolate pooled diagnostic accuracy.[50]
Result
nests of basaloid cells showing palisading in the peripheral cell layer at the dermoepidermal junction and/or in the dermis
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