3) These tumors have more mitotic figures and fewer shadow cells
when compared with nonproliferative pilomatricomas, and they are fast-growing, large lesions.
Pilomatricomas are composed of two types of cells namely basophilic and shadow cells
with areas of calcification (Fig.
If fine-needle aspiration is performed, the diagnosis of PM may be made only if all major components of PM are present in the aspirate, including calcium deposition, basaloid cells and keratinized ghost or shadow cells
There is a study suggesting that apoptosis is the main mechanism leading to the development of the dead shadow cells
and is most probably responsible for the biological behaviour of pilomatricoma.
Finding follicular bulbs, papillary mesenchymal bodies, trichohyalin granules, hair shafts, shadow cells
, and focal CD34 staining in adjacent tumor stromal cells all favor benign entities.
FNA of the lesion commonly reveals basaloid cells, squamous cells, anucleate squames, shadow cells
, foreign-body giant cells, polymorphs, and calcification in variable frequencies.
Tumors are well-circumscribed, dermal to subcutaneous nodules composed of several components, including basaloid proliferation, shadow cells
, dystrophic calcifications, and foreign-body giant-cell reactions (figure 1).
There were squamoid cells with adjacent shadow cells
Several nests of shadow cells
, wet keratin and keratin pearls are present [Figure 3].
In the dermis, there were many cystic spaces lined by basaloid cells with shadow cells
on the luminal surface and central eosinophilic areas of keratinization.
(ghost cells/ anucleate squames): non--nucleated keratinized squamous cells with distinct cell borders and central pale nuclear zone, present singly or in clumps.
In 1922, Dubreuilh and Cazenave described the unique histopathological characteristics of this neoplasm, including islands of epithelial cells and shadow cells