Development of dermatomyofibroma in a male infant

Inhibition of Integrin-Associated Kinases FAK and ILK on the In Vitro Model of Skin Wound Healing

Dermal fibroblasts are essential cells of skin tissue responsible for its normal functioning. In skin wounds, the differentiation of resident fibroblasts into myofibroblasts occurs, which is accompanied by the rearrangement of actin cytoskeleton with the expression of alpha-smooth muscle actin. This transformation is a prerequisite for a successful wound healing. At the same time, different studies indicate that extracellular matrix may be involved in regulation of this process. Since the connection between cells and matrix is provided by transmembrane integrin receptors, this work was aimed at studying the dynamics of signaling pathways associated with integrins on an in vitro model of wound healing using human skin fibroblasts. It was shown that the healing of simulated wound was accompanied by a change in the level of integrins as well as integrin-associated kinases ILK (integrin-linked kinase) and FAK (focal adhesion kinase). Pharmacological inhibition of ILK and FAK caused the suppression of p38 and Akt which proteins are involved in regulation of the actin cytoskeleton. Moreover, it resulted in an inefficient wound closure in vitro. The results of this study support the involvement of integrin-associated kinases in regulation of fibroblast-to-myofibroblast transition during wound healing.

A lesson in clinicopathological correlation: Plaque-like myofibroblastic tumour presenting as a pruritic plaque in childhood

Plaque-like myofibroblastic tumour (PLMT) is a rare skin condition which presents in childhood and infancy as a nodular fibrous plaque. Including our case, there are currently only 14 cases reported in the literature. Although it represents a well-defined clinicopathological diagnosis, there is significant under-reporting of this condition secondary to under-recognition and potential misdiagnosis as dermatofibroma.

[Anatomoclinical and immunohistochemical study of 8 cases of dermatomyofibroma]

INTRODUCTION

Dermatomyofibroma (DMF) is a rare, benign tumour that is little-known among clinicians. However, it has typical clinical, histological and immunohistochemical features that distinguish it from other fibrous tumours.

METHOD

We report herein on the clinical, histological and immunohistochemical aspects of eight cases of DMF identified between 2008 and 2019 at the dermatopathology laboratory of Strasbourg.

RESULTS

Five men and three women of average age at diagnosis of 21 years and 9 months (range: 9 to 54 years) were included. Lesions ranged in size from 1 to 11cm. Most cases involved the upper body (6 cases), with one case on the abdomen and one on the side. The lesions presented as a solitary asymptomatic red or reddish brown nodule or plaque that gradually developed. The plaques were hard and caused functional discomfort on movement of the neck. Well-circumscribed spindle cell proliferation was noted in the reticular dermis parallel to the epidermis, without mitotic figures or cytological atypia. The subcutis was infiltrated in 5 cases. Expression of calponin was positive in all cases but one, while that of caldesmon, PS100 and desmin was negative. Expression of smooth muscle actin was positive in 2 cases, and both cases were also positive for stromylesin-3. CD34 was positive in 2 cases.

DISCUSSION

DMF is an extensive tumour capable of attaining large diameters and must be completely excised. The main differential diagnoses of DMF are dermatofibrosarcoma protuberans, dermatofibroma, fibrous hamartoma, myofibromatosis and cheloid. It can be identified based on various factors, whether clinical (young age, extensive lesion), histological (horizontal proliferation in the reticular dermis) or immunohistochemical (positive expression of calponin).

Multiple dermatomyofibromas

This study describes a case of a 19-year-old patient with seven asymptomatic lesions on the chest, measuring between 0.5 to 1cm in diameter, with no history of trauma in the region. The immunohistochemical evaluation was positive for vimentin and smooth muscle actin, determining Dermatomyofibroma as definitive diagnosis. Dermatomyofibroma is a benign skin tumor, with a myofibroblastic origin, prevalent in young women. It usually presents as a single lesion, with very few reports of multiple lesions.

Dermatomyofibromas Arising in Children: Report of Two New Cases and Review of the Literature

Dermatomyofibroma is a rare, benign mesenchymal proliferation not commonly reported in children. Two patients with biopsy-proven dermatomyofibroma were identified (one female, one male) at our institution, both with rather atypical clinical presentations. The clinical and histopathologic findings and a review of the literature are presented here. Features of dermatomyofibroma should be recognized and differentiated from those of similar-appearing entities since the prognosis of this benign tumor is favorable after complete excision.