Hans Wilhelm Kaiser

Cutaneous angiomyxoma: a benign neoplasm distinct from cutaneous focal mucinosis.

We describe a cutaneous angiomyxoma on the head of a 38-year-old man without evidence of Carneys complex. Complete excision of the tumor appeared to be curative. Histologic examination revealed fibroblast-like cells embedded in a well-demarcated, lobulate, mucinous, and vascularized stroma with a delicate reticulin network. Immunohistologically, the stromal cells were consistently positive for vimentin and focally positive for smooth muscle A-actin but were negative for desmin, KP1, MAC387, factor XIIIa, CD34, Leu-7, and S-100. Cutaneous angiomyxoma appears to represent a myofibroblastic neoplasm that should be distinguished from cutaneous focal mucinosis.

Das sklerotische Fibrom

ZusammenfassungDie klinische und histologische Diagnose sklerotischer Fibrome ist wegen ihrer potentiellen Assoziation mit der Cowdenschen Erkrankung von Bedeutung. Trotz ihrer distinkten histologischen Struktur bleibt die Läsion häufig fehlinterpretiert. Daher berichten wir über 5 eigene Patienten (2W, 3M), bei denen am Kopf (n=2), Arm (n=2) und Bein (n=1) entsprechende Tumoren beobachtet wurden. Die Läsionen imponierten klinisch als weiße bis fleischfarbene harte Knoten, die zwischen 0,5 und 1,2 cm maßen. Klinische Hinweise für das Vorliegen der Cowdenschen Erkrankung fanden sich bei keinem unserer Patienten. Die einfache chirurgische Exzision scheint kurativ zu sein. Histologisch waren die dermalen Tumoren gut umschrieben aber nicht abgekapselt und aus ineinander verflochtenen Kollagenfaserbündeln sowie fibroblastenähnlichen Zellen zusammengesetzt, bei 3 Patienten mit einigen Myofibroblasten. Ca. 50% der Zellen (dermale Dendrozyten (DD)) exprimierten zusätzlich Faktor XIIIa und waren gleichmäßig innerhalb der Tumoren verteilt, im Gegensatz zu den sehr wenigen (<5%) CD34+ DD, die vor allem in den unteren Tumoranteilen beobachtet wurden. Diese Befunde mögen die Verteilung der DD in normaler Haut widerspiegeln. Das sklerotische Fibrom erweitert das Spektrum von Bindegewebstumoren mit potentiell myo-fibroblastischer Differenzierung.SummaryThe clinical and histological diagnosis of sclerotic fibroma is important because of its potential association with Cowdens syndrome. Despite its distinctive histological appearance the lesion is often misdiagnosed. We therefore present five of our own cases (2F, 3M) in which the tumor was located on the head (n=2), arm (n=2) and leg (n=1), respectively. Clinically, the lesions were white to flesh-colored firm nodules ranging in size from 0.5 to 1.2 cm. None of our patients revealed any clinical evidence of Cowdens disease. Simple surgical excision seems to be curative. Histologically, they were well-circumscribed but not encapsulated dermal nodules composed of storiform-arranged sclerosing collagen bundles and vimentin-positive fibroblastlike cells interspersed in three cases by a number of α-smooth-muscle actin-positive myofibroblasts. Approximately 50% of cells (dermal dendritic cells (DD)) also reacted for factor XIIIa evenly scattered throughout the lesion in contrast to the very few (<5%) CD34+ DD found predominantly at the lower border, thus possibly reflecting the distribution of these cells in normal skin. Sclerotic fibroma expands the spectrum of fibrous lesions that may express α-smooth-muscle actin.

Observation, Modeling and Simulation of Keratinocyte Movement

Migration of human epithelial keratinocytes (HEK) on glass in culture medium has been observed by video-microscopy. Depending on the concentrations of epidermal growth factor (EGF) and Ca-ions, cells show a variety of characteristic shape deformations. Single cells exhibit (often pulsative) protrusions and retractions of lamellipods, mostly accompagnied by a steady retrograde flow of visible “ruffles”, and dynamic changes in concentration and orientation of the cortical cytoskeleton surrounding the “cell body”. Both processes induce continuing shape changes of cells, which are either freely migrating or moving as pairs or in smaller groups. Keratinocytes have obvious functions during wound healing, namely to cover free space, to establish effective cell-cell contacts and to form connected cell tissues under high tension. Responsible for these effects is the dynamic (re-)distribution of a contractile “machinery” consisting of actin filaments, crosslinking proteins and adhesion receptors, cf. Kaiser et al. (1989, 1993).