Janik, I., Hubacek, J., Tomášková, L., Dvorackova, J. Tichy, M. Hilserova, I., Kovarikova, J.

 

Abstract

Laser Treatment Center in Olomouc performed operations on 542 patients (141 males, 401 females) for melanocyte and non-melanocyte skin tumors with CO₂ laser during the period between January 2001 and June 2002. Histologies determined 1222 naevi in total, a detailed overview of individual types is shown in Tables 1 and 2.

The authors mention specifics of CO₂ incision, ways of healing and surgical techniques. Surgeon must bear in mind a good cosmetic result of an operation as well as the necessity of obtaining a proper diagnosis through an adequately radical excision enabling a thorough histopathological examination of the whole of the sample including its edge and base, i.e . the removal of the entire tumor.

 

Keywords

Melanocyte and non-melanocyte skin tumors, CO₂ laser surgery.

 

Introduction

Accrual in incidence of malignant melanomas and skin carcinomas has been noticed recently, as well as their occurrence in younger age cathegories. The number of patients with malignant melanoma in white race increases more rapidly than patients with all other solid malignant neoplasms. During the last decade incidence of malignant melanoma in the population of modern European countries has fluctuated between 2 - 15 cases of 100,000 inhabitants per year. Malignant melanoma forms in about two thirds of cases de novo, whilst in about one third it is the case of malignant reversal of previously non-malignant melanocyte lesion (4). Risk factors include genetic predisposition, UV radiation, constitution attributes, number of melanocyte naevi and particularly their dysplastic forms (4).

Incidence of skin carcinomas has been increasing, too. In Australia and the USA the number of new basalomas is estimated at more than 600 cases of 100,000 inhabitants per year. On the other hand, in the Czech Republic only less than 70 new skin tumors of 100,000 inhabitants per year were reported, which is apparently a very undervalued number (6).

Skin tumors are attended to by dermatologists, general surgeons, plastic surgeons, otorhinolaryngologists, dental surgeons, ophtalmologists, and pathologists. They can be treated with actinotherapy, cryotherapy, electrocoagulation. The most frequent surgical procedure is excision followed by histological examination. Apart from classical excision with a scalpel, so called harmonic scalpel, radiosurgery and laser have been employed in recent years. Our experience with a CO₂ laser is the subject of this paper.

 

Initial observations

Laser Treatment Center (LTC) has been always using CO₂ lasers. At present the parameters of the device used are as follows: spot size 0.1 mm, power output 1 - 40 Watt (0.5 - 15 W in superpulse mode), with the possibility of application of CW or pulsed mode. For skin surgeries incisions with 5 - 10 W power are quite sufficient, or 0.8 -1 W in superpulse mode. No significant differences have been detected by histological examinations, incisions with the use of superpulse mode show smaller zone of carbonization.

Advantages of laser incision, i.e. sterility, non-contact, low or no bleeding, minor post-op oedema, and limited dissemination of tumor cells, are very useful in skin surgery. However, one should also pay attention to specifics of healing of laser incisions.

Between January 2001 and June 2002 LTC operated melanocyte and non-melanocyte skin tumors in 542 patients (141 males, 401 females) with CO₂ laser. Histological examinations were provided Cytological Laboratory in Ostrava. Tables 1 and 2 show results on the basis of histological findings in individual excisions. The group thus does not include patients with only vaporization of minor lesions - fibromas, haemangiomas, verrucas etc. Dermatol had been usually applied after the excision, and after the separation of the crust scars were treated according to initial condition (Framykoin, Dermazulen, Panthenol, Beloderm, Acnepur etc.). Complicated healing is mentioned in Table 3. Check-ups after surgeries were performed in the course of healing. Clinically doubtful patients with multiple naevi as well as patients in whom malignities or risk of malignity were ascertained by  the histological examination were hospitalized in dermatology and oncology unit of SPEA.

 

Discussion

Two points of view clash in laser surgery of skin tumors. On one hand there is a request to respect lege artis procedures - to determine a proper diagnosis and remove a tumor completely - whilst, on the other hand, doctors opt for less radical surgical techniques in pursuit of accomodating the demands of patients who prefer a quick heal up with a perfect cosmetic result. However, in order to be able to determine a right diagnosis it is unconditionally necessary to carry out a histological analysis of the whole of the sample including the margins and the base of the lesion.

Laser excision differs from classical excision with a scalpel. The distinction follows from characterictics of a laser cut. The area of initial vaporization of tissue, resulting from focussed spot of laser beam (0.1 - 0.2 mm), continues in zone of carbonized residues of tissue (30 and more µm), then a zone of thermal necrosis up to 300  µm comes, followed by a transient area (500  µm and more) with decreasing cellular damage. Then there is a zone of hyperemia and oedema where changes are reversible, and an intact zone comes last. Width of the zones fluctuate depending on characteristics of tissue as well as on cutting parameters of the laser, its type, output power, diameter of the spot, speed of the cut and infiltration anamnesis.

The progress of the healing differs, too. Within 24 hours after CO₂ incision even slightly damaged cells on the margin of the transient area get to necrosis. In the boundary of the necrosis and the vital tissue an intensified exudatively inflammatory reaction appears, mostly due to neutrophilic leucocytes. The whole of the area of necrosis (zone of carbonization, thermal damage and transient area) separates in seven days and the defect gets filled with granulation tissue. New epidermis apears in 14 days, the wound is redintegrated in the area of corium with a fibrous scar, vascularization persists only focally, massive cellular granulomas appear round carbonized fragments here and there. Within a month the scar consists of a grown-up connective tissue, however still rich in fibrocytes, massive cellular granulomas with carbonized material appear in the subcutis sporadically, and connective tissue in their vicinity is more voluminous. In three months the scar is formed by grown-up connective tissue, with tissue in subcutis noticeably vascularized focally (13, 14). 

LTC utilizes CO₂ laser in clinical practice in several ways:

1. Vaporization of minor tumors - fibromas, haemangiomas, verrucas etc.
2. Close excision of the boundary of the tumor, probatory excision and vaporization of the residue of the tumor
3. Close excision of the boundary of the tumor, excision with scissors or extirpation of the base of the tumor with a tangential laser cut, vaporization of the margins of the cut or, in the event of using scissors, even of the base of the excision
4. Extirpation of the tumor with a cut leading at 1 - 2 mm distance from the margins of the tumor in sound tissue. The surgery can only be performed with laser, or it is possible to use scissors to separate the base of the tumor.

Laser incision on the basis of the tumor requires lifting it up with a retractor, forming a skin fold when using scissors. A defocussed beam is recommended to treat a bleeding lesion. Vaporization makes a histological examination impossible, in case of a probatory excision only a part of the tumor is taken, a close excision of the tumor damages the margins of the incision thermically and makes histological evaluation difficult. Extirpation of the tumor with the edging of a sound tissue is the most appropriate way of surgery from the point of view of oncology.  

With regards to the fact that some centers prefer only vaporization in case of surgery of a tumor with a CO₂ laser, as a consequnce some negative aproaches have appeared, not recommending laser operations particularly of naevi at all. For example Mestak warns of laser surgeries because "they do not allow complete removal of a naevus and, at the same time, any irritation regardless to whether mechanical, chemical or thermal, can result in a malignant change in the rest of the tissue (8)."

In LTC surgical extirpation of the tumor is preferred. After close excision of the tumor followed by vaporization of its margins and the base histological findings usually state that the tumor reaches the boundary of the excision. However, even a massive vaporization of the margins and the base of the lesion does not ensure that the tumor had been removed in full. Thus in case of diagnostic doubt a re-excision is necessary.

In LTC we do not indicate gradual vaporization of naevi layer by layer, usually called ablation. However, according to Brychta (1) the risk connected with laser ablation of some naevi is so small, that laser ablation can be carried out provided the surgery is sufficiently radical and predeceded by a histological sampling. In the   vaporization is suitable. Subsequent procedures depend on the result of histology as well as on healing.

Individual groups of melanocyte naevi are shown in Table 1. In the course of one session 10 naevi were operated at the most, or repeatedly. Highest number of naevi in a single patient was 22.

Dysplastic naevi were diagnosed in 6 patients (2 males, 4 females) of total number of 11 patients. Spitz`s naevus was detected in 30 years old man.

A very rare minimally deviating melanoblastoma (3, 7, 10) was diagnosed in a 23 years old woman who had to undergo a preventive excision of a naevus at her back due to irritation with clothes. Histological expertise detected an intradermal naevus (6 mm) with a minimally deviating 1.5 mm melanoblastoma, Clarc IV, at the centre of it. As the excision extended to thermically changed margins a re-excision was conducted after the wound had healed up.

Occurrence of different types of naevi in one individual was quite frequent. There was a case of a 25 years old female patient on whom 9 naevi were operated, histology determined 1 fibropapiloma, 5 dermoepidermal naevi, 1 intradermal naevus, and 2 dysplastic naevi.

Basalomas were detected in 9 patients (4 males, 5 females), in 1 case in two localities. Basalomas appear mainly in the face, approximately in 80 - 90 % (2, 9). Our patients had all their basalomas in the face, in 4 cases in the area of the nose. Those were eliminated by extirpation. In 2 women and 1 man with suspicion of basaloma the suspective zones were vaporized after taking an excision for a histological examination. Histologies confirmed pseudoepiteliomatous hyperplasias and chronical inflammation.

A spinaloma was diagnosed in a 50 years old woman complaining for several weeks of a spherical formation 8 x 8 mm in inflammatory area in her left eyebrow, from which she used to squeeze a thick fluid from time to time. After the formation, resembling an infected cyst, was extirpated, histology identified a well differentiated spinocellular carcinoma.

Hypertrophic scars and keloids occurred in 186 cases. This number seems rather high. However, it is necessary to take into account that about 1/4 of hypertrophic scars appeared after vaporization, as well as that in some patients with predisposition to hypertrophic or keloid scarring those scars emerged after excisions in high count (18 and 20 scars in two women, 15 scars in one man). Healing process must be followed and patients instructed, although some do not respect recommendations and appear for check ups only with massive keloids. Treatment of hypertrophic and keloid scars is easier in their initial stages, conservative healing with application of Hirudoid, Contratubex, Diprophos inj., LLLT laser irradiation, or quicker and more effective with vascular surgical laser (570 - 590 nm, 40 - 60 J/cm2, several pulses, three times in monthly intervals).     

Pigmented scars appeared in 41 cases. Temporary brown colorization can also be caused by residual carbonized tissue, however it disappears after a month. Initial pigmentation originates from pigment cells of adnexal structures, or from adjacent intact skin (1, 12). Some minor pigmentations in thea scar sooner or later disappear by themselves, it is also possible to apply Retin A locally, or to use laser vaporization. Brychta recommends radical excision. In more noticeable pigmentations excision of the scar, or of a part of the scar with pigment, was indicated, and histological examinations indicated several causations of pigmentation:

1. melanine corpuscles in upper corium extracellularily,
2. conspicuous pigmentation of the basal layer of new epidermis,
3. structures of intradermal naevus - residual of unsufficiently excised naevus.

In one patient, where there had been an intradermal naevus determined by the first excision, scarry ligament and residua of naevi structures in minor areas as well as in dermoepidermal junction were determined by the second excision performed due to pigmentation in the scar.

Re-excisions were instructive due to another aspect, too. In the scarry ligament of corium there was increased vascularization noticed even three months after the excision, thus long-time flare of the scar is no reason for both the patient and the physician to worry, because it relates to the healing of the laser wound, as it has been proved also in experimental excisions in animals (13).

 

Conclusion

There is no doubt that high power lasers represent a great asset to surgery. CO₂ laser as one of the first surgical lasers still remains widely used in therapy of skin tumors, and modern units boost with excellent parameters, even though guiding of the beam through optical fibres is still not common. Despite of the fact that a CO₂ laser in treatment of skin tumors has been used twenty years ago (5) and its usefulness and advantages have been proved in the course of time, yet it is not fully appreciated. As it can be seen in this paper, therapy of skin tumors is a team work of a dermatologist, a surgeon, a histopathologist and an oncologist. 

 

Melanocyte naevus	Quantity	Per cent
Dermoepidermal	247	20.2
Intradermal	960	78.6
Dysplastic	11
Spitz`s naevus	1
Blue naevus	2
Melanoblastoma	1

Table 1: Melanocyte naevi

 

Non-melanocyte skin tumors	Quantity	Per cent
Basaloma	10	3.6
Spinaloma	1	-
Fibropapiloma	93	33.5
Histiocytoma	8	2.9
Haemangioma	5	1.8
Angiofibroma	7	2.5
Neurofibroma	2	-
Lipoma	4	1.4
Atheroma	7	2.5
Verruca seborrhoica	109	39.2
Verruca vulgaris	14	5.0
Hyperkeratosis	18	6.5

Table 2: Non-melanocyte skin tumors

 

Complication	Quantity	Per cent
Hypertrophic scar - keloid	186	80.2
Pigmentation in scar	41	17.7
Hairs in scar	5	2.1

Table 3: Complicated healing

 

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