The study lot of 15 patients had the final diagnoses, histopathologically confirmed, of 3 basal cell carcinoma, 1 keratoacanthoma, 4 actinic keratoses, 1 Bowen disease, 2 sebaceous hyperplasia, 1 Kaposi’s angio–sarcoma, 1 sebaceous cyst and 2 dermatofibromas. Six lesions could not be evaluated by OCT, because of too high elevation of the lesion, patient's movement or unfavorable location. Within the control lot, 3 patients were diagnosed with psoriasis, 1 with cutaneous lupus erythematosus, 1 with cutaneous sarcoidosis, and for comparison we analyzed also 2 seborrheic keratoses.
Normal skin structures
Our preliminary results demonstrated that OCT was useful in visualizing and differentiating skin layers and structures such as epidermis, papillary and reticular dermis, dermal blood vessels, hair follicles and glandular ducts (–).
Normal skin, OCT aspect. Extensor aspect forearm, 53 year old male; E epidermis, D Dermis, rD reticular dermis, white arrows: hair follicles
Normal skin, OCT aspect. Thigh, 53 years old female, E: epidermis, D: dermis, white arrows: blood vessels
It also distinguished the thickness and structure variations according to different skin types, anatomical location and age. Generally, the epidermis appeared darker as the underlying dermis, with dermo–epidermal junction clearly visible in most images. Dark, signal–poor, round or thin branched spaces appeared in the dermis, corresponding to different–sized blood vessels. Stratum corneum was visible as a thin bright line. Reticular dermis structures were usually effaced.
Normal skin. Volar aspect of index finger; (A). OCT aspect: E epidermis, D dermis (dermal papillae), white arrows: sweat ducts; (B). Clinical aspect of dermatoglyphs
Actinic keratoses and Bowen's disease
The actinic keratoses and the in situ squamous cell carcinoma (–) showed various degrees of epidermal thickening, with lesional epidermis appearing darker, possibly due to increased keratin content. An overlying dark irregular band corresponding to hyperkeratosis was present. The lateral limits of the lesions were visible as well as the dermal–epidermal demarcation. Within the in situ squamous cell carcinoma () the marked increased thickness of epidermis is highly irregular and scales appearing bright are visible.
Figure 5 Actinic Keratosis, OCT aspect. E: epidermis, slightly thickened in the lesional area; Arrowhead: signal–poor irregular band corresponding to hyperkeratosis; D dermis; asterisc black: round signal–free structures corresponding to dilated (more ...)
Figure 6 Bowen's Disease, OCT aspect. E: epidermis, which in the lesional area is markedly thickened, irregular, hypo–dense; one hair follicle appears to be involved; Hyperkeratosis is also marked, with a scale (arrowhead) partially detached. There is (more ...)
Basal cell carcinoma
The basal cell carcinomas that we evaluated through OCT (–) showed characteristic lobular signal–poor structures which occupied the dermis and corresponded on the histopathology examinations to tumoral lobules. One tumor depicted () was a superficial BCC showing ulceration, the other () was nodular of solid type. Signal attenuation in the dermis in OCT did not allow proper assessment of the tumor limits in depth, beyond 1 mm.
Basal cell carcinoma. (A) OCT aspect, ; lobular signal–poor structure, corresponding to tumoral lobules; E epidermis, D Upper dermis; Upper dark band corresponds to keratin–rich stratum corneum; (B) Clinical aspect
Figure 8 Basal cell carcinoma, nodular type, OCT aspect. OCT aspect: ; signal–poor lobulated structures corresponding to tumoral lobules; D upper dermis; arrow: thin epidermis, difficult to distinguish from underlying dermis; arrowhead: round signal–free (more ...)
Interestingly, in one patient with early lesions of Kaposi's sarcoma OCT scanning showed a nodular area of signal attenuation in the dermis, corresponding to histopathological and clinical aspect of a small incipient angio–sarcomatous nodule (). Within it, branched, reticular or round signal–poor/free structures were visible, corresponding to vascular spaces and clearly demarcated from the unaffected perilesional dermis. The epidermis was distinguishable from underlying dermis, with flattening over the lesion.
Figure 9 Kaposi Sarcoma. (A) OCT aspect, focal changes in the central lesional area, showing a flattened epidermis (E), irregular, partly round partly branched and reticular signal–ppoor/free structures (asterisc) corresponding to vascular spaces, and (more ...)
Two seborrheic keratoses, with typical clinical aspect were included as control lesions in the study. On OCT they showed characteristical changes () as compared to normal skin, with marked thickening of the epidermis with papillomatous aspect, as well as superficial rounded hypo–dense structures, unsharply demarcated, which corresponded to horn pseudocysts; these latter structures were easy to differentiate from the more uniformly dark, and sharp–demarcated round/oval ones corresponding to vessels visualized in OCT. Increased thickness of epidermis was associated with marked signal attenuation over the dermis.
Figure 10 Seborrhoic keratosis. (A) OCT aspect E: epidermis, which in the lesional area, on the right half of the image shows marked thickening, with papillomatous aspect, as well as rounded hypo–dense structures (asteriscs), possibly corresponding to horn (more ...)
Inflammatory skin lesions
The control lesions we included in the study comprised 3 psoriasis lesions (), which in OCT showed typical thickening of the epidermis, with protrusions in the dermis, strong hyperkeratosis as a darker superficial band and signal–poor rounded structures in the dermis corresponding to dilated vessels. Another control case of sarcoidosis showed in OCT hypo–dense confluent rounded masses occupying the dermis, and corresponding on histopathology exam to granulomatous infiltrates ().
Figure 11 Psoriasis, OCT aspect. Epidermis (E) is hypo–dense and in the lesional area (left) is markedly thickened, with elongated protrusions in underlying dermis (D); overlying marked focal hyperkeratosis, as dark band, with scales protruding (arrowhead). (more ...)
Figure 12 Cutaneous Sarcoidosis.(A) OCT aspect showing signal–poor agglomerated masses (asteriscs) occupying the dermis in the lesional area ( left), corresponding to granulomatous infiltrates. E epidermis; D dermis unaltered in the right extreme of the (more ...)