[Photodiagnostic tests. 3: Fluorescence diagnosis with delta-aminolevulinic acid-induced porphyrins (FDAP) in dermatology]

Clinical Benefits of Preoperative Conventional Fluorescence Diagnosis in Surgical Treatment of Extramammary Paget Disease

BACKGROUND

In extramammary Paget disease (EMPD), initial margins of surgical excision are difficult to determine preoperatively. Fluorescence diagnosis (FD) may have utility as a noninvasive method for delineating tumor boundaries.

OBJECTIVE

The relationship between FD-delineated borders and results of multiple scouting biopsies (MSBs) in EMPD was investigated, evaluating the potential clinical role of FD.

MATERIALS AND METHODS

A cohort of 21 patients was studied, looking for consistencies between FD and MSB results. Initial surgical margins were determined by FD or FD plus MSB. All margins were subjected to frozen section analysis.

RESULTS

Paget cells were identified in 88 of 117 (71.8%) biopsies obtained from FD borders. When used preoperatively with MSB in 9 patients, 96.4% of margins proved negative at initial resection stage. Using a 6-mm margin beyond FD borders in another 9 patients, 86.7% of margins were negative at initial stage. The maximum distance of excision beyond FD border was 12 mm.

CONCLUSION

Fluorescence diagnosis borders (identified visually) correlated well with MSB histopathology. Fluorescence diagnosis is a useful method to delineate initial margins for surgical resection of EMPD.

Protoporphyrin IX fluorescence as potential indicator of psoriasis severity and progression

BACKGROUND AND OBJECTIVES

In psoriatic lesions, fluorescence diagnosis with blue light can detect protoporphyrin IX accumulation, especially after topical 5-aminolaevulinic acid (ALA) application. However, variable fluorescence distributions, interpersonal variations and long incubation time limit its wide application in clinic. This study is aimed to identify a consistent and convenient method to facilitate diagnosis and evaluation of psoriatic lesions.

METHODS

104 psoriatic lesions from 30 patients were evaluated. Single lesion PSI scoring and fluorescence by macrospectrofluorometry were recorded on each lesion before and after treatment with narrow-band UVB.

RESULTS

Punctate red fluorescence, emitted mainly by protoporphyrin IX, is observed in some psoriatic lesions. According to psoriasis severity index, fluorescence-positive lesions are more severe than lesions without fluorescence. We found a significant positive correlation between psoriasis severity and fluorescence intensity from protoporphyrin IX.

CONCLUSIONS

Protoporphyrin IX-induced red fluorescence can be used as a novel and convenient approach for psoriasis diagnosis and progression evaluation.

The effects of keratolytic pretreatment prior to fluorescence diagnosis and photodynamic therapy with aminolevulinic acid-induced porphyrins in psoriasis

BACKGROUND

Psoriasis lesions accumulate protoporphyrin IX (PpIX) with a variable distribution within plaques due to variations in hyperkeratosis causing differences in penetration of cream or light.

OBJECTIVES

To study the effects of different keratolytic pretreatments in PpIX-induced fluorescence diagnosis (FDAP) and during photodynamic therapy (PDT).

METHODS

Two psoriasis plaques of 10 patients were treated with either topical retinoic acid or with a hydrocolloid dressing. The hydrocolloid dressing gave the best results. Subsequently, two different contralateral plaques of eight patients were pretreated with a hydrocolloid dressing or the standard pretreatment, salicylic acid in petrolatum, during the 6 weeks of PDT. Biopsies were investigated with respect to stratum corneum thickness, proliferation, differentiation and inflammation.

RESULTS

Irritation and point bleedings were noticed after retinoic acid. A hydrocolloid dressing induced the best clinical improvement. Therefore, it was used as alternative pretreatment for psoriasis prior to PDT. We observed significant clinical and immunohistochemical improvement of psoriasis in the salicylic acid as well as the hydrocolloid dressing pretreated plaques.

CONCLUSIONS

Salicylic acid in petrolatum and a hydrocolloid dressing prior to FDAP and PDT induce improvement of hyperkeratosis. Thus, a hydrocolloid dressing is a good alternative to the current keratolytic pretreatment regime.

Heterogeneity of fluorescence in psoriasis after application of 5-aminolaevulinic acid: an immunohistochemical study

BACKGROUND

Psoriasis has been shown to highly accumulate protoporphyrin IX (PpIX), but a variable distribution within plaques after fluorescence diagnosis is seen. It is unknown what causes this heterogeneity of fluorescence in psoriatic skin, despite adequate keratolytic treatment. Variations in fluorescence might explain the variable and the mostly partial clinical response of psoriasis seen after photodynamic therapy (PDT).

OBJECTIVES

This study examines morphological and immunohistochemical differences in inhomogeneous PpIX-induced fluorescence in stable plaque psoriasis.

MATERIALS AND METHODS

Fourteen patients with stable plaque psoriasis were included in this study. In each patient one psoriatic plaque was incubated with 20% 5-aminolaevulinic acid (ALA) ointment for 3 h after keratolytic treatment. Fluorescence diagnosis with ALA-induced porphyrins (FDAP) was performed and subsequently high- and low-fluorescent psoriatic skin samples were biopsied. Biopsies were investigated with respect to histological hyperkeratosis (thickness of stratum corneum), proliferation (Ki-67 antigen), keratinization (K10, filaggrin) and inflammation (CD3). Digital images acquired with FDAP were analysed using image analysis software.

RESULTS

Inhomogeneous fluorescence was seen in 12 of the 14 plaques. A significantly thicker stratum corneum was found in low-fluorescent psoriatic skin compared with highly fluorescent skin. Fluorescence intensity and thickness of the stratum corneum proved to be negatively correlated. The variable-fluorescent parts of the lesional psoriatic skin showed no differences in epidermal proliferation, keratinization or inflammation.

CONCLUSIONS

Heterogeneous ALA-induced fluorescence in psoriasis plaques related to inhomogeneous distribution of PpIX in the epidermis may result from differences in penetration of ALA and/or light within a plaque caused by differences in stratum corneum thickness. The variable clinical response seen after PDT in psoriasis could be explained by this. These findings are consistent with the general assumption that optimal desquamation prior to FDAP or PDT is required for the most favourable results.

Bispectral fluorescence imaging of aggressive basal cell carcinoma combined with histopathological mapping: a preliminary study indicating a possible adjunct to Mohs micrographic surgery

BACKGROUND

Fluorescence imaging is an attractive diagnostic technique for skin tumour demarcation with potential to move to clinical use. Bispectral fluorescence imaging combines skin autofluorescence with delta-aminolaevulinic acid-induced fluorescence. To evaluate the technique, fluorescence data must be compared with the histopathological extent of the tumour, which is the purpose of the current study.

OBJECTIVES

To investigate the agreement between bispectral fluorescence images and the histopathological tumour boundary of ill-defined basal cell carcinomas (BCCs). After fluorescence imaging the tumours were removed using Mohs micrographic surgery (MMS) to obtain histopathological maps of the tumour boundaries.

METHODS

Twelve patients with aggressive BCC of mean diameter 16 mm (range 5-32) in the face were included in the study. The patients were subjected to bispectral fluorescence imaging within the 2 months prior to MMS. The fluorescence images and histopathological maps were aligned using image warping.

RESULTS

Five patients (42%) showed good agreement with the histopathological mapping and the remaining seven patients (58%) showed partial agreement. Bispectral investigation combining autofluorescence with protoporphyrin IX (PpIX) fluorescence generally yielded better agreement with the histopathological boundaries of the tumours compared with using only the PpIX fluorescence.

CONCLUSIONS

In this preliminary study the fluorescence has been compared with the histopathological tumour boundaries. The result implies that the technique can be applied as a useful tool for indicating tumour boundary of aggressive BCCs. Further refinement is needed to be able to indicate the exact tumour border.

Correlation Between Macroscopic Fluorescence and Protoporphyrin IX Content in Psoriasis and Actinic Keratosis Following Application of Aminolevulinic Acid

In fluorescence diagnosis with 5-aminolevulinic acid (ALA)-induced porphyrins (FDAP), protoporphyrin IX (PpIX) accumulation can be macroscopically visualized. Interpretation of these data is still problematic because of the low reproducibility of the procedure and poor understanding of the mechanisms involved in PpIX tumor selectivity. In this study, PpIX accumulation is investigated in patients with psoriasis and actinic keratosis (AK) following FDAP. For this purpose, desquamated lesional and non-lesional skin were incubated with 20% ALA ointment for 3 h, FDAP was performed, and highly fluorescing lesional skin and non-lesional skin were biopsied. In extracts from these biopsies, PpIX, protein, and dsDNA were quantified by spectrofluorometry. Digital images acquired with FDAP were analyzed using image analysis software. PpIX per biopsy in lesional skin in both psoriasis and AK was significantly higher than in non-lesional skin (p < 0.05). When corrected for epidermal involvement, only lesional psoriatic skin showed significantly higher PpIX levels than non-lesional skin. The PpIX-ratio lesional:non-lesional skin (mean(pmol per mL)+/-SEM) was 4.12+/-0.91 in psoriasis and 1.96+/-0.24 in AK. In FDAP, the ratio of lesional:non-lesional skin was 1.77+/-0.06 in psoriasis and 1.37+/-0.07 in AK. Macroscopic fluorescence and PpIX content appeared to be well correlated (r = 0.73), thus making FDAP a good predictor of PpIX content.

Fluorescence contrast and threshold limit: implications for photodynamic diagnosis of basal cell carcinoma

This study was designed to evaluate what application time of delta-5-aminolaevulinic acid (ALA) results in highest contrast between tumour and normal skin, in the interval 1-4 h, when using photodynamic diagnosis (PDD) of basal cell carcinomas (BCC) located on the face. Moreover, a value of the demarcation limit has been derived based on the fluorescence variation in normal skin adjacent to the tumour. Forty patients were included in the study, randomly allocated to four different groups with varying ALA application time in the range 1-4 h. The contrast, defined as the ratio between the fluorescence intensity in ALA-treated tumour tissue and normal skin, was calculated for each patient, and the mean values in each group were evaluated as a function of ALA application time. In addition, the fluorescence intensity variation in ALA-treated normal skin adjacent to the tumour was assessed. The results from this study show a peak of the mean contrast values after 3 h ALA application, but due to large interpatient variation, the mean contrast did not differ significantly in the interval 2-4 h. After 2 h ALA application, the fluorescence intensity variation in the normal ALA-treated skin was found to be at a maximum, which suggests that 2 h ALA application is not preferable when using PDD. Based on data of the fluorescence variation in ALA-treated normal skin after 3 and 4 h ALA application, a tolerance interval was calculated implying that values above 1.4 times the mean normal fluorescence indicate an abnormal condition. This tolerance limit agrees well with results obtained in a former study.

Basal cell carcinoma: treatment options and prognosis, a scientific approach to a common malignancy

The incidence of basal cell carcinoma is rapidly increasing and a number of treatment modalities are available. Treatment of basal cell carcinoma includes both surgical and nonsurgical approaches, some of which are traditional, and others experimental. The treatment modality utilized is dependent on both the tumor type and the patient. In order to choose between therapies, evidence-based research is necessary. In an extensive review of the literature concerning treatment options for patients with basal cell carcinoma, we found that there are a limited number of comparative, prospective, randomized, long-term follow-up studies. Based on the results of the available studies, surgical excision, Mohs surgery and cryosurgery are the three standard therapies of choice. Other treatment modalities should be considered secondary choices. There are also promising new treatment options, such as photodynamic therapy, which need further investigation. Special attention is needed when treating the more aggressive subtypes of the disease, such as the micronodular, infiltrative, adenoid and morpheic forms of basal cell carcinoma, as well as bigger basal cell carcinomas and basal cell carcinoma recurrences.