SUMMARY. After a brief description of the actiopathogenesis of carcinoma occurring in burn scars, some such cases are presented that were observed in the upper limb. It is concluded that these tumours can be avoided by preventive treatment of unstable scars.

Introduction

Skin carcinoma, of both basocellular and 1 spinocellular form, can develop in scar tumour. In particular, it may occur in a burn scar (Marjolin's ulcer) (2, 4).
Various actiopathogenctic theories have been suggested (4, 6) but the one with widest support is the hypothesis of chronic irritation.
Among burn scar sequelae (hypertrophy and/or keloid, retraction, unstable scar), the unstable scar is the form liable to develop skin carcinoma (1).
A scar is said to be unstable when it corresponds to a zone of such fragile repair that the slightest trauma can cause it to ulcerate. This condition may occur in scars from burns allowed to heal spontaneously without covering by skin graft. Generally, however, they are retracting scars either in a pressure area, or at the level of flexor surfaces, or in any other area subject to movement. Because of the constant state of tension the scar ulcerates repeatedly, and on each occasion the healing time is more and more protracted until healing in fact no longer occurs, owing to the onset of epitheliomatous degeneration (3). The latency period between the burn and malignant transformation is extremely varied, but in general it is a matter of years: the problem of the cancer which after many years develops in unstable burn scars is in fact part of the vaster problem of the malignant transformation of chronic lesions that are subjected to continuous irritative stimuli.
The process of epithelialization of an open lesion is characterized by the mitotic activity of the epithelial cells which for this purpose dedifferentiate and migrate. Contact inhibition, due to the encounter and cell adhesion, is the phenomenon that generally puts an end to the process. If however the lesion is too extensive to epithelialize, or is subjected to continual traumas, this phenomenon may not occur and the epithelial cells may continue not to be differentiated, dividing up and becoming mobile. It is this continual stimulation, in the attempt to achieve healing only through epithelialization, that determines the develooment of abnormal characteristics, among which is an increase in the mitosis rate, in some cells at the margins of the lesion, and - in the long term -in the cancer rate (8).
These conditions may easily occur at the level of the upper limb which is a site of continual movement; this study concerns the cases that we have observed of cutaneous epithelioma of the upper limb occurring in burn scars.

Between 1975 and 1990 we treated 37 cases of epithelloma in the upper limb, 13 of which (35.13%) were basallomas and 24 (64.87%) spinallomas. Of the latter, 6 (25%) occurred in burn scars, 2 (8.33%) in other lesions (trauma, actinic keratosis), while in the remaining 16 cases (66.67%) no precise anamnestle data were available.

Case 1

M.G., male, age 62 years, admitted in September 1983 with the diagnosis of "recidivation of neoplasia in burn sequela in dorsal lower third left forearm", presented with a walnut-sized vegetating-ulcerated neoformation. Anamnesis revealed that the burn occurred in the patient's childhood. In November 1974, in another hospital, he was subjected to exeresis of a neoformation in a burn scar on the left elbow. This was followed by the onset of a torpid ulcer which in June 1975, in our Department, was covered by an abdominal flap. In 1982 the patient presented with an onset of ulceration (histological tests showed a spinocellular epithelloma of medium-grade differentiation) in the left forearm, which was subjected to extensive excision and free skin graft. Recidivation, after one year, was not accompanied by clinically positive regional lymph nodes and it was retreated, under narcosis, with ample excision of the tumour and covering by a free skin graft obtained with a Padgett dermotome. Histological tests indicated a spinocellular, well differentiated, keratinizing epithelloma which totally infiltrated the fragment examined. The patient was therefore sent for radiotherapy. Since the therapeutic treatments he has not presented further local recidivations or lymph node metastases (Figs. I a, b, c).

Case 2

M.S., mate, age 54 years, admitted in May 1983 with the diagnosis of "neoformation on the dorsal surface of the left hand occurring in a burn scar", presented with a vegetating neoplasia about 2 x 2 cm in size. Anamnesis revealed that the neoformation initiated ten years after the bum. On admission there was no clinical evidence of metastatic regional lymph node involvement. The surgical operation, under narcosis, consisted of an ample excision of the tumour with covering by means of free skin graft. Histological tests revealed a mature spinocellular carcinoma (Broders 1) and the poles and fundus of the resected part were unaffected. The patient did not have local recidivations or metastases becoming evident following removal of the tumour (Figs. 2a, b).

Fig. 1- a. Covering with abdominal nap of torpid ulcer occurring after excision performed in another hospital of carcinoma in burn sequela on left elbow Fig. 1 - b. Long-term flap check-up Fig. 1 - c. Recidivation ofneoformation on burn scar appearing after about 8 years in distal third of left forearm in same person

Fig. 2 - a. Neoformation in burn scar on dorsal surface of left hand Fig. 2 - b. The excised neoformation

S.G., male, age 65 years, was admitted in November 1983 with the diagnosis of "ulcerated neoformation in a burn sequela on the dorsal surface of the right hand". Anamnesis indicated a bum sustained at the age of 2 years, with a latency therefore of 63 years before appearance of the tumour. On admission the patient did not present lymph gland involvement. The tumour was removed, under narcosis, with ample excision, and covering was by free skin graft. Histological tests indicated a differentiated spinocellular carcinoma (Broders 11). The margins of the resected part were free of neoplasia. The patient had no local recidivation or lymph node metastases following the operation.

M.F., male, age 72 years, admitted in August 1987 with the diagnosis of "neoformation in a burn sequela in the left hand-, presented with an ulcerated neoplasia 2.5 x 2.5 em in size. The burn had been sustained some 40 years previously. The patient did not present palpable lymph nodes and the tumour was amply removed under narcosis. The bloody area was covered with free skin graft. Histological tests indicated a mature spinocellular carcinoma (Broders 1). The poles and fundus of the resected part were unaffected. The patient did not subsequently present recidivation or lymph node metastases.

B.V., male, age 60 years, was admitted in November 1987 with the diagnosis of -neoformation in a burn scar in the dorsal surface of the right handand presented with a vegetating neoplasia sized 12 x 4 em. It was not stated when exactly the burn occurred. There was no lymph node involvement and the operation, under narcosis, consisted of an ample excision of the tumour and covering by means of free skin graft. Histological tests indicated a mature spinocellular epithelioma (Broders 1) and the margins of the resected part were not affected by neoplasia. The patient did not present recidivation or lymph node metastases following the operation.

C.P.G., male, age 51 years, admitted in July 1989 with the diagnosis of "neoformation in a burn scar in the fold of the left elbow", presented with an ulcerated abscessed neoplasia the size of a walnut. Anamnesis indicated that the burn, caused by tar, had been sustained 10 years previously and that since then the residual scar had suffered various ulcerative episodes treated with unspecified medical therapy. In the absence of clinically appreciable lymph nodes, the operation consisted, under narcosis, of an ample excision as far as the fascia, followed by covering with free skin graft. Histological examination revealed a well-differentiated spinocellular carcinoma, with poles and fundus of the resected part unaffected by infiltration. So far the patient, since the operation, has not presented recidivation or lymph node metastases.

Conclusion

According to Dufourmentel (3), carcinomas developing in an unstable scar have the following three characteristics:

1. Clinical diagnosis is diflicult because the onset is insidious, as it is the result of a progressive transformation.
2. Its evolution remains local for a long time and it develops much more on the surface than in depth.
3. The appearance of lymph node metastases, makes the prognosis unfavourable.

Surgical treatment of the tumour, when already present, must therefore be performed in good time; early therapy can lead to complete and permanent recovery. Removal of the regional lymph nodes, if clinically positive, offers only limited survival. Results obtained with prophylactic lymphadenectomy have also proved to be no longer encouraging (5, 7).
Given these circumstances, as all unstable scars may in time undergo cancerous transformation, it becomes of fundamental importance to treat them preventively in order to safeguard the tissue.
Surgical treatment (free grafts or flaps) must therefore have a dual objective:

1. permanent recovery;
2. prevention of malignant degeneration after many years (1).

RÉSUMÉ. Les auteurs, après avoir décrit brièvement l'étiopathologie des carcinomes qui se produisent sur les cicatrices par brûlure, présentent les cas qu'ils ont observés à niveau du membre supérieur, en concluant que ces tumeurs peuvent être évitées par moyen du traitement préventif des cicatrices instables.

BIBLIOGRAPHY

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