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Histology of port wine stains following argon laser treatment
HISTOLOGY OF PORT WINE STAINS FOLLOWING ARGON LASER TREATMENT By DAVIDB. APFELBERG, M.D., F.A.C.S.,* JON KOSEK,M.D.,? MORTONR. MASER,M.D., F.A.C.S.* and HARVEYLASH, D.D.S., M.D.* * Department of Plastic and Reconstructive Surgery, Palo Alto Medical Clinic; -r Department of Pathology, Palo Alto Veterans Administration Hospital
THE argon laser has now been firmly established as an effective treatment of certain port wine stain haemangiomas (Apfelberg et al., 1977; Goldman and Dreffer, 1977) and we have studied the histological changes which occur following treatment. MATERIALANDMETHODS Laser treatment was applied in the following manner: Following adequate local anaesthesia with 2 per cent plain xylocaine, an average of 1,100 to 1,500 laser impulses at 1.8 to 2.0 watts with a 0.2 second pulse duration were applied to the haemangioma which was divided into a-square-inch treatment segments.
Fig.
Note thin-walled distended blood vessels through dermis. H. & E. x 75. Fig. 2. Skin with port wine stain immediately after laser therapy. There is coagulative necrosis of the upper dermal collagen and the entire epidermis, with disruption of the latter and a homogenised appearance of the former. H. & E. Deep portions of appendages are intact. x 75. I.
Port
wine stain, untreated.
Address for reprints: Palo Alto Medical Clinic,
David B. Apfelberg, M.D., Department of Plastic and Reconstructive 300 Homer Avenue, Palo Alto, California 94301, USA. 232
Surgery,
HISTOLOGY
OF PORT
WINE
STAINS
233
Biopsies were obtained from 30 patients selected randomly, before treatment, immediately afterwards and at varying follow-up times to 7 years. A standard 3 mm skin punch was used following local plain xylocaine infiltration. Portions of each sample were fixed in Zenker’s solution for paraffin sections and in I ‘5 per cent glutaraldehyde in cacodylate buffer at pH 7.3 with added sucrose for tonicity, of 300 millosmoles, The paraffin sections were imbedded in epon and prepared for electron microscopy. stained with H. & E. in every case and with Gomori’s trichome, Wilder’s reticulum, and Verhoef’s elastic tissue stains, where appropriate. RESULTS
Immediately after treatment, blisters formed rendering the treated area white or grey. Microscopically there was coagulative necrosis of the entire epidermis and of the uppermost dermal collagen (Figs. I and 2). There was also small vessel thrombosis and necrosis extending more deeply. Sweat glands, hair follicles, and sebaceous glands were similarly affected superficially, but more deeply they were only minimally damaged. After the initial vesicle, a crust formed on the skin which persisted 7 to 14 days. It then separated from a pink or reddened intact skin surface. The pink colour began to fade in 2 to 3 months and continued to lighten for 6 to 15 months after treatment. Intermediate and later (6 to 36 months) histological changes correlated with this stage
Pig. 3.
Note absence of haemangioma, some fibrosis Site of port wine stain, 6 months after treatment. \(75. of upper dermis, normal epidermis, and dermal appendages. H. h E.
l;Ig. 4.
The small vessels are without Site of port wine stain, 7 years post treatment. moderate fibrosis. H. & E. y dO0.
ectasia;
there i\
234
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Fig. 5. Port wine stain vessel in untreated skin. There is a red blood cell (RBC) in the lumen (I). Also shown is an endothelial cell (EN), subjacent basement membrane and collagen (C). Electron micrograph. x IS,OOO. Fig. 6. Port wine stain vessel, about 5 minutes after treatment, showing extreme denaturation of the endothelial cells, with homogenised nuclear structure (EN) outlined by small arrows; lumen (I) is collapsed. Electron micrograph. x 10,000.
of fading and were limited to the upper I mm of dermis. These changes included variable proliferation of collagen, a markedly decreased number of small blood vessels, and compression of remaining blood vessels into slit-like structures, sometimes with abnormally thick walls (Fig. 3). The epidermis appeared normal or only slightly atrophic and there was a paucity of upper dermal blood vessels. Persistence of sweat glands and pilosebaceous structures was usual but not invariable. Seven years following laser treatment the changes were similar and appeared to be stable and permanent (Fig. 4). Cellular and nuclear dystrophy was not apparent in either the epithelium or the dermal In the late lesions, the mesenchymal cells, and inflammatory cells were very infrequent. upper I mm of dermis was typically diffusely fibrotic, with relatively few residual vessels, many of them with abnormally thickened walls and slit-like contour (Fig. 4). The overlying epidermis was apparently normal and the dermal appendages were either normal in number and structure, or less frequent, but qualitatively normal. Electron microscopy immediately after laser impact showed collapse of the haemangioma vascular lumens, vacuolation and otherwise denaturation of both endothelial cells and karyocytes, as well as fibrocytes and other cells in the upper dermis, and apparent fractionation of the vascular basal membranes (Figs. 5 and 6).With healing, the residual vessels had abnormally thick collagenous walls and very poorly defined basement membranes, but otherwise lacked distinctive features (Fig. 7).
HISTOLOGY
I;ig. 7. Vessel in upper dermis irregular, basement membrane
OF PORT
WINE
STAINS
235
Endothelium (ENj is intact though from an area treated 6 months before. is very poorly defined, and a dense collagenous matrix (C) surrounds the vessel. Electron micrograph. * 15,000.
DISCLXSION
The argon laser provides a reliable system for the delivery of intense focusable thermal energy to the dermal vascular network of port wine stains (Solomon et uZ., 1968). Red cell haemoglobin absorbs the blue-green laser light, transforming the radiant energy into heat, which coagulates blood vessels up to 0.5 mm in diameter. Adjacent skin appendages are relatively less damaged and are able to participate in the IHistologically the injury to the upper dermis is reconstruction of normal epidermis. seen to be followed by rapid healing which leaves essentially normal epidermis and diffuse mild upper dermal fibrosis. These changes have been permanent and stable over a T-year period. It has been demonstrated in the above studies that the argon laser used in this fashion delivers appreciable energy to only the upper I mm of dermis; therefore, those port wine haemangiomas that are confined to this area or above respond favourably (Figs. 8 and 9). In lesions which have vessels deeper in the dermis, for example at the level of sweat glands at a depth of 2 to 2: mm, a less satisfactory result has occurred in over 20 such cases. Figure IO demonstrates that although the upper dermal vessels of such a lesion have been eliminated and replaced by collagen after laser therapy, a significant portion of the lesion remains in the deeper dermis. Tlhe result was rated as onlv fair in this case.
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236
Fig. 8.
Pretreatment
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view of a port wine stain in a 34-year-old woman. Note the test patch in the upper corner of the haemangioxa near the hairline.
Fig. g After treatment there was good blanching of the lesion without scarring. This lesion was confined to the upper I mm of dermis. (Treatment at 1.8 watts, 0.2 seconds pulse duration, I mm spot size, 3,500 individual laser pulses.)
Fig.
IO.
a. Untreated
H. & E. x 40. port wine stain, with deep dermal involvement. The deep portion of the lesion persists. H. & E. x 40.
b. After treatment.
HISTOLOGY
OF
PORT
WINE
STAINS
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CONCLUSION
Treatment of port wine stains by the argon laser produces thermal damage to the upper I mm of dermis. Dermal appendages are preserved and aid in the rapid healing of the wound. Treated skin has been observed over a T-year period, and the changes have proved to be permanent and stable, suggesting that laser wounds are “safe” without the risk of future malignant changes. Moreover, prediction of “‘favourable” versus “unfavourable” lesions is now possible histologically since lesions having aberrant vessels which are largely confined to the upper I mm of dermis may be expected to respond favourably to this form of treatment, while deeper lesions may persist as suboptimal blanching or only modest lightening of the haemangioma colour. REFERENCES APFELBERG, D. B., MASER, M. R. and L.ASH, H. (1977). Argon laser treatment of cutaneous vascular abnormalities : progress report. Annals of Plastic Surgery, I, 14. GOLDMAN, L. and DREFFER, R. (1977). Laser treatment of extensive mixed cavernous and port-wine stains. Archives of Dermatology, 113, 504, SOLOMON, H., GOLD~MAN, L., HENDEKSON, B., RICHFIELD, D. and FRANZEN, M. (1968). Histopathology of the laser treatment of port-wine lesions. Journal of Investigative Dermatology, 50, 141.
THE argon laser has now been firmly established as an effective treatment of certain port wine stain haemangiomas (Apfelberg et al., 1977; Goldman and Dreffer, 1977) and we have studied the histological changes which occur following treatment. MATERIALANDMETHODS Laser treatment was applied in the following manner: Following adequate local anaesthesia with 2 per cent plain xylocaine, an average of 1,100 to 1,500 laser impulses at 1.8 to 2.0 watts with a 0.2 second pulse duration were applied to the haemangioma which was divided into a-square-inch treatment segments.
Fig.
Note thin-walled distended blood vessels through dermis. H. & E. x 75. Fig. 2. Skin with port wine stain immediately after laser therapy. There is coagulative necrosis of the upper dermal collagen and the entire epidermis, with disruption of the latter and a homogenised appearance of the former. H. & E. Deep portions of appendages are intact. x 75. I.
Port
wine stain, untreated.
Address for reprints: Palo Alto Medical Clinic,
David B. Apfelberg, M.D., Department of Plastic and Reconstructive 300 Homer Avenue, Palo Alto, California 94301, USA. 232
Surgery,
HISTOLOGY
OF PORT
WINE
STAINS
233
Biopsies were obtained from 30 patients selected randomly, before treatment, immediately afterwards and at varying follow-up times to 7 years. A standard 3 mm skin punch was used following local plain xylocaine infiltration. Portions of each sample were fixed in Zenker’s solution for paraffin sections and in I ‘5 per cent glutaraldehyde in cacodylate buffer at pH 7.3 with added sucrose for tonicity, of 300 millosmoles, The paraffin sections were imbedded in epon and prepared for electron microscopy. stained with H. & E. in every case and with Gomori’s trichome, Wilder’s reticulum, and Verhoef’s elastic tissue stains, where appropriate. RESULTS
Immediately after treatment, blisters formed rendering the treated area white or grey. Microscopically there was coagulative necrosis of the entire epidermis and of the uppermost dermal collagen (Figs. I and 2). There was also small vessel thrombosis and necrosis extending more deeply. Sweat glands, hair follicles, and sebaceous glands were similarly affected superficially, but more deeply they were only minimally damaged. After the initial vesicle, a crust formed on the skin which persisted 7 to 14 days. It then separated from a pink or reddened intact skin surface. The pink colour began to fade in 2 to 3 months and continued to lighten for 6 to 15 months after treatment. Intermediate and later (6 to 36 months) histological changes correlated with this stage
Pig. 3.
Note absence of haemangioma, some fibrosis Site of port wine stain, 6 months after treatment. \(75. of upper dermis, normal epidermis, and dermal appendages. H. h E.
l;Ig. 4.
The small vessels are without Site of port wine stain, 7 years post treatment. moderate fibrosis. H. & E. y dO0.
ectasia;
there i\
234
BRITISH
JOURNAL
OF
PLASTIC
SURGERY
Fig. 5. Port wine stain vessel in untreated skin. There is a red blood cell (RBC) in the lumen (I). Also shown is an endothelial cell (EN), subjacent basement membrane and collagen (C). Electron micrograph. x IS,OOO. Fig. 6. Port wine stain vessel, about 5 minutes after treatment, showing extreme denaturation of the endothelial cells, with homogenised nuclear structure (EN) outlined by small arrows; lumen (I) is collapsed. Electron micrograph. x 10,000.
of fading and were limited to the upper I mm of dermis. These changes included variable proliferation of collagen, a markedly decreased number of small blood vessels, and compression of remaining blood vessels into slit-like structures, sometimes with abnormally thick walls (Fig. 3). The epidermis appeared normal or only slightly atrophic and there was a paucity of upper dermal blood vessels. Persistence of sweat glands and pilosebaceous structures was usual but not invariable. Seven years following laser treatment the changes were similar and appeared to be stable and permanent (Fig. 4). Cellular and nuclear dystrophy was not apparent in either the epithelium or the dermal In the late lesions, the mesenchymal cells, and inflammatory cells were very infrequent. upper I mm of dermis was typically diffusely fibrotic, with relatively few residual vessels, many of them with abnormally thickened walls and slit-like contour (Fig. 4). The overlying epidermis was apparently normal and the dermal appendages were either normal in number and structure, or less frequent, but qualitatively normal. Electron microscopy immediately after laser impact showed collapse of the haemangioma vascular lumens, vacuolation and otherwise denaturation of both endothelial cells and karyocytes, as well as fibrocytes and other cells in the upper dermis, and apparent fractionation of the vascular basal membranes (Figs. 5 and 6).With healing, the residual vessels had abnormally thick collagenous walls and very poorly defined basement membranes, but otherwise lacked distinctive features (Fig. 7).
HISTOLOGY
I;ig. 7. Vessel in upper dermis irregular, basement membrane
OF PORT
WINE
STAINS
235
Endothelium (ENj is intact though from an area treated 6 months before. is very poorly defined, and a dense collagenous matrix (C) surrounds the vessel. Electron micrograph. * 15,000.
DISCLXSION
The argon laser provides a reliable system for the delivery of intense focusable thermal energy to the dermal vascular network of port wine stains (Solomon et uZ., 1968). Red cell haemoglobin absorbs the blue-green laser light, transforming the radiant energy into heat, which coagulates blood vessels up to 0.5 mm in diameter. Adjacent skin appendages are relatively less damaged and are able to participate in the IHistologically the injury to the upper dermis is reconstruction of normal epidermis. seen to be followed by rapid healing which leaves essentially normal epidermis and diffuse mild upper dermal fibrosis. These changes have been permanent and stable over a T-year period. It has been demonstrated in the above studies that the argon laser used in this fashion delivers appreciable energy to only the upper I mm of dermis; therefore, those port wine haemangiomas that are confined to this area or above respond favourably (Figs. 8 and 9). In lesions which have vessels deeper in the dermis, for example at the level of sweat glands at a depth of 2 to 2: mm, a less satisfactory result has occurred in over 20 such cases. Figure IO demonstrates that although the upper dermal vessels of such a lesion have been eliminated and replaced by collagen after laser therapy, a significant portion of the lesion remains in the deeper dermis. Tlhe result was rated as onlv fair in this case.
BRITISH
236
Fig. 8.
Pretreatment
JOURNAL
OF
PLASTIC
SURGERY
view of a port wine stain in a 34-year-old woman. Note the test patch in the upper corner of the haemangioxa near the hairline.
Fig. g After treatment there was good blanching of the lesion without scarring. This lesion was confined to the upper I mm of dermis. (Treatment at 1.8 watts, 0.2 seconds pulse duration, I mm spot size, 3,500 individual laser pulses.)
Fig.
IO.
a. Untreated
H. & E. x 40. port wine stain, with deep dermal involvement. The deep portion of the lesion persists. H. & E. x 40.
b. After treatment.
HISTOLOGY
OF
PORT
WINE
STAINS
237
CONCLUSION
Treatment of port wine stains by the argon laser produces thermal damage to the upper I mm of dermis. Dermal appendages are preserved and aid in the rapid healing of the wound. Treated skin has been observed over a T-year period, and the changes have proved to be permanent and stable, suggesting that laser wounds are “safe” without the risk of future malignant changes. Moreover, prediction of “‘favourable” versus “unfavourable” lesions is now possible histologically since lesions having aberrant vessels which are largely confined to the upper I mm of dermis may be expected to respond favourably to this form of treatment, while deeper lesions may persist as suboptimal blanching or only modest lightening of the haemangioma colour. REFERENCES APFELBERG, D. B., MASER, M. R. and L.ASH, H. (1977). Argon laser treatment of cutaneous vascular abnormalities : progress report. Annals of Plastic Surgery, I, 14. GOLDMAN, L. and DREFFER, R. (1977). Laser treatment of extensive mixed cavernous and port-wine stains. Archives of Dermatology, 113, 504, SOLOMON, H., GOLD~MAN, L., HENDEKSON, B., RICHFIELD, D. and FRANZEN, M. (1968). Histopathology of the laser treatment of port-wine lesions. Journal of Investigative Dermatology, 50, 141.