So far, studies on the mechanism of scar formation have mainly focused on cells, cytokines and extracellular matrix. Some studies have shown that fibroblast is one of the most important element in the process of scar formation, while epidermal and endothelial cells exert synergistic effects as well. Genetic factor can not be ignored in scar formation, either. Recently, studies have shown decisively the loss or damage of the three-dimensional structure of dermal tissue is the initiator of scar formation. Thus, the defect of epidermis template is proposed as a theory in order to explain the mechanism of scar formation. There are various techniques for scar treatment. The commonly accepted methods are physical therapy, pressure therapy, pharmaceutical therapy, radiotherapy, etc.
Cicatrix ; metabolism ; pathology ; therapy ; Dermis ; pathology ; Humans

Dermal defection and the degree of its loss determine the natural process of wound healing, which is the key reason leading to excess scar hyperplasia. The function of tri-dimensional structure in dermis acts as a template to regulate the properties of reparative cells. The template structure induces the reparative cells to grow into the structure which changes the skin mechanic status on wound area. Also, the component of extracellular matrix can affect behaviours of fibroblasts negatively or positively, for the reason that the structure of dermal tissue has a permissive effect on the dermal components in regulating behaviours of reparative cells. Therefore, the behaviors of cells depend on the structure of the template. The suitable tri-dimensional structure of dermis facilitates normal cell cycling. The more the structure of dermis closed to its physiological status, the better the biological behaviors of cells act. Moreover, the integrity as well as the continuity of dermal tissue is the prerequisite for serving as a template. The damage to the integrity and the continuity of dermal tissue may be one of the key reasons to lead abnormal tissue repair and scar formation. Thus, we hypothesize that the loss of dermal template may be one of the mechanism of abnormal scar formation and propose the theory of extracellular matrix framework deficiency or destruction.
Cicatrix ; pathology ; Dermis ; pathology ; Epidermis ; pathology ; Humans ; Wound Healing

We reported two cases of clinically typical melasma presenting with unusual histopathologic findings. In one case, the epidermal melanocytes were markedly increased in number and protruded into the dermis, and in the other case, increased epidermal pigmentation as well as dermal melanocytosis were found. We suggested that the various treatment modalities of melasma should be applied depend on its histopathologic finding.
Melanosis/*pathology ; Melanocytes/pathology ; Humans ; Female ; Epidermis/pathology ; Dermis/pathology ; Adult

Artificial dermis is a kind of tissue engineering dermal substitute and is used to repair dermal defects caused by a variety of reasons. This article describes the characteristics and the mechanism of repair and reconstruction of bilayer artificial dermis. Based on domestic experience of clinical applications and relative literature of bilayer artificial dermis, more than 50 domestic experts in related field reached a consensus on indications, contraindications, operation procedures in clinical application, cautions, and treatment and prevention of complications of bilayer artificial dermis, providing reference for clinical application.
Consensus ; Dermis ; pathology ; Skin Transplantation ; methods ; Skin, Artificial ; Tissue Engineering

OBJECTIVETo explore the influence of dermal defect and fat dome structure destruction in burn wounds on the formation of hyperplastic scar.

METHODSFifty two wounds in 24 burn patients with deep partial thickness burn indicating tangential excision in the extremities were enrolled in the study, and they were divided into three groups according to the extent of exposure of dermal fat granules, i.e. A (without fat exposure), B (with little fat exposure) and C (with much fat exposure) groups. These three groups were subdivided into A1 (without grafting), A2 (grafting with razor thin skin), B1 (without grafting), B2 (with razor thin skin grafting), C1 (without grafting) and C2 (with split-thickness skin grafting) groups, with 9 wounds in each group. The dermal depth and exposure rate of the fat granules in each group were measured and analyzed by KS400 photography analysis apparatus. The follow-up conditions of the scars 6 months after operation were evaluated with Vancouver remark system by Vancouver score assessment.

RESULTSThere was obvious difference in the dermal depth and exposure rate of the fat granules among all the groups (P < 0.05 or 0.01). The fat exposure rate was positively correlated with the extent of the dermal defect (gamma = 0.554, P < 0.05). The Vancouver score in group A was lower than that in B and C groups (P < 0.05), while that in B1 group (3.714 +/- 2.498) was evidently higher than that in other groups (P < 0.01). The scar score was lowered when the wounds were grafted with the dermis with its thickness similar to the depth of the defect, The scar score was increased along with the elevation of fat exposure rate (P < 0.05).

CONCLUSIONThere was a positive correlation between the degree of dermal defect and that of hyperplastic scar after burns. The disruption of fat dome structure might also be an important factor in the scar development.

Adipose Tissue ; pathology ; Adult ; Burns ; complications ; pathology ; Cicatrix, Hypertrophic ; etiology ; pathology ; Dermis ; pathology ; Female ; Humans ; Male ; Middle Aged ; Wound Healing

Aged ; Dermis ; pathology ; Disease Progression ; Extremities ; Face ; Fatal Outcome ; Humans ; Male ; Sarcoma, Myeloid ; pathology ; Skin ; pathology ; Thorax

To establish a simple and reliable animal model of skin photo-damage, 20 mice were treated with 8-MOP and exposed to UVA (UVA 320-400 nm) for 24 h. After irradiation, the structure of the epidermis and dermis, collagen fibers, elastic fibers were observed by using HE staining and Weigert technique and compared with the normal controls. The acanthosis and epidermis proliferation with accompanying hyperkeratosis and parakeratosis were observed. Inflammatory infiltration was noted in the dermis. The elastic fibers became coarse, irregularly arranged and clustered, with their number increased. The collagen fibers showed obvious degeneration and some amorphous materials could also be observed. The blood vessels were irregularly dilated and vascular walls were thickened, with infiltration of inflammatory cells. It is concluded that murine photodamage model can be quickly, conveniently and reliably established by means of 8-MOP/UVA.
Dermis/pathology ; Disease Models, Animal ; Epidermis/pathology ; Methoxsalen/*pharmacology ; Photosensitizing Agents/pharmacology ; Skin/*pathology ; Skin Aging ; Ultraviolet Rays

Fifty-two cases of neurilemmoma, which occurred in the skin and soft tissue and filed at the Department of Clinical Pathology, Catholic University Medical College from 1974 to 1984, were included for the clinical study. Forty four cases whose microscopic slides were available were reviewed for the histopathologic observation. The results were as follows : Clinical observations 1) The average age of the patients was 42.8% years old, and the average duration of tlie tumor was 3.9 years. 2) Eight cases were acompanied with tenderness and cases with tingling sensation. Clinica] signs described prior to biopsy were palpable mass(15), slow growing mass (8), palpable cystic mass(6) and hard mass(4). 3) The mean diameter was 2.6m (0.45cm-8cm), and the frequent sites were head and neck (32.7%), upper extremities(28.8%), lower extremities (23.11%) and trunk (15.4%) in decreasing orders. Histopathologic observations 1) 33 cases were composed of both Antoni A and type B with variable composition, but only Antoni type A was observed in 6 cases and Antoni type B in 5 Cases. 2) On the areas of Antoni type B, there were several degenerative changes including cystic change (52.3%), hemorrhage(50%), hyalinization(27.3%), necrosis(25%), and calcification(4.5%). 3) In 3 cases out of 44, the tumor was observed in the dermis and the tumors composed of Antoni A only occurred on the tongue, neck, and upper arm.
Arm ; Biopsy ; Dermis ; Head ; Humans ; Lower Extremity ; Neck ; Neurilemmoma* ; Pathology, Clinical ; Sensation ; Skin ; Tongue

This clinical and histopathological study was performed with 147 cases of benign mielanocytic tumors and 19 cases of malignant melanomas, which were obtained as surgical specimens from 1974 to 1984 at Department of Clinical Pathology, Catholic Medical College. The results were as follows: 1, In 89 cases of acquired benign melanocytic nevi, the average age of intradermal type(64 cases) was 34. 7 years and that of compound type(24 cases) was 24. 6 years. 2. In 30 cases of congenital nevus, nevus cells were present in the lower two thirds of reticular layer of the dermis in 93. 3% and in the subcutis as well in 3.3%. A case of giant congenital nevus with balloon cell appearance was found. 3. Of the 147 benign melanocytic tumors, a pigmented spindle cell nevus and a desmoplastic nevus were observed. 4. Blue nevi were 11 in number and excised from the face in 7, buttock in 2, shoulder in 1, upper arm in 1, and all were common type histopathologically. 5. Twelve malignant melanornas which were possible to be re-examined histopathologically were composed of 5 nodular type, 3 acral lentiginous type, 1 superficial spreading type and 3 metastatic malignant melanoma.
Arm ; Buttocks ; Dermis ; Melanoma* ; Nevus ; Nevus, Blue ; Nevus, Pigmented ; Nevus, Spindle Cell ; Pathology, Clinical ; Shoulder

OBJECTIVETo investigate the effects of three kinds of artificial dermal scaffolds on vascularization and scar formation of wounds in pigs with full-thickness burn.

METHODSEighteen Bama miniature pigs were divided into chitosan scaffold (CS) group, sulfonated carboxymethyl chitosan scaffold (SCCS) group, and acellular dermal matrix (ADM) scaffold group according to the random number table, with 6 pigs in each group. Every pig in all groups was inflicted with 4 or 8 full-thickness scald wounds on the back (totally 96 wounds). Forty-eight hours after injury, eschars of all wounds were excised. Twenty-four wounds in CS group were transplanted with double-layer artificial dermis of collagen-chitosan and silicone rubber, those in SCCS group with double-layer artificial dermis of collagen-sulfonated carboxymethyl chitosan and silicone rubber, and those in ADM scaffold group with ADM. The rest 24 wounds in the three groups were dressed with vaseline gauze as control group. After 2 weeks of treatment, all wounds of every group were covered with skin. In post treatment (scaffold transplantation or gauze covering) week (PTW) 1, 2, 3, and 4, gross condition of wound was observed, and specimens from central parts of wounds were harvested for observation and assessment of vessels or cells with positive expression of CD31, α smooth muscle actin (α-SMA), TGF-β(1) and TGF-β(3) with SP staining. Data were processed with one-way analysis of variance and LSD test.

RESULTS(1) Degree of vascularization in SCCS group was better than that in the other three groups. (2) The number of vessels with positive expression of CD31 in CS, SCCS, ADM scaffold, and control groups increased gradually from PTW 1 to PTW 3, and decreased in PTW 4. There were statistical differences among 4 groups from PTW 1 to PTW 4 (with F value respectively 24.005, 38.822, 25.274, 3.856, P < 0.05 or P < 0.01). The numbers of vessels that expressed CD31 in SCCS group from PTW 1 to PTW 3 were more than those in the other three groups (with P values all below 0.05). (3) The numbers of vessels that expressed α-SMA in CS, SCCS, and ADM scaffold groups from PTW 1 to PTW 3 showed the similar trend of change to those of vessels that expressed CD31, which increased gradually in control group from PTW 1 to PTW 4. There were obvious differences among 4 groups from PTW 1 to PTW 4 (with F value respectively 22.637, 28.087, 62.651, 18.055, P values all below 0.01). The number of vessels that expressed α-SMA in SCCS group from PTW 1 to PTW 4 was more than that in the other three groups (with P values all below 0.05). (4) From PTW 1 to PTW 4, the number of cells with expression of TGF-β(1) in CS group was respectively (127 ± 8), (167 ± 19), (170 ± 18), (144 ± 10) per 400 times visual field, that in SCCS group was respectively (171 ± 17), (207 ± 25), (130 ± 30), (69 ± 16) per 400 times visual field, that in ADM scaffold group was respectively (106 ± 8), (159 ± 17), (171 ± 11), (145 ± 11) per 400 times visual field, and that in control group was respectively (100 ± 20), (150 ± 18), (200 ± 14), (172 ± 20) per 400 times visual field. There were statistical differences among 4 groups from PTW 1 to PTW 4 (with F value respectively 29.675, 9.503, 13.107, 54.515, P values all below 0.01). Compared with those in SCCS group, the number of cells that expressed TGF-β(1) in the other three groups was decreased in PTW 1, 2 but increased in PTW 3, 4 (with P values all below 0.05). (5) The number of cells that expressed TGF-β(3) in 4 groups increased gradually from PTW 1 to PTW 3, and decreased or increased continually in PTW 4. There were statistical differences among 4 groups from PTW 1 to PTW 4 (with F value respectively 140.612, 945.850, 714.037, 119.147, P values all below 0.01). The number of cells with positive expression of TGF-β(3) in SCCS group from PTW 1 to PTW 4 was more than that in the other three groups (with P values all below 0.05).

CONCLUSIONSThe collagen-sulfonated carboxymethyl chitosan dermal scaffold can rapidly induce growth and maturation of blood vessels during wound healing after burn. It is beneficial for wound repair at early stage with inhibition of scar proliferation.

Acellular Dermis ; Animals ; Burns ; surgery ; Chitosan ; analogs & derivatives ; Cicatrix ; pathology ; Collagen ; Dermis ; transplantation ; Female ; Neovascularization, Physiologic ; Skin Transplantation ; Skin, Artificial ; Swine ; Tissue Scaffolds ; Wound Healing