Die Metamorphose des Epithelioma calcificans Malherbe

Immunohistochemical expression of bone morphogenetic protein-2 in pilomatricoma

“…Depending on its stage of differentiation, pilomatricoma is classified into three phases: a progressive phase, a regressive phase, and the phase of dismantling and reconstruction by stroma. 5 In the progressive phase, basophilic cells, which are located in peripheral areas of long‐standing tumour, lose their nuclei and differentiate abruptly into shadow cells that are located in the centre of the tumour. Then, in the regressive phase, most pilomatricomas contain calcium deposits and amorphous necrotic products of degeneration in the centre of shadow cells.…”

Pilomatricoma. A clinical, histopathologic and histochemical study of 22 patients

“…It takes place in the stroma next to areas of shadow cells, probably through metaptasis of fibroblasts into osteoblasts [13]. Calcium rich shadow ceils thereby act as an inducing factor [17]. It seems that the peculiar transformation of these germinative cells into shadow cells, resembling epidermal prickle cells, and their strong tendency to calcify are evidence of profound discruption of normal cellular metabolism [17].…”