Abstract
A malignant trichilemmoma(mTr) is histopathologically composed of basaloid cells with Bowen’s disease-like changes such as clumping cells and dyskeratosis, and glycogen-rich clear cells with low atypicality. Utilizing tumor cells from the lesion of mTr in the right leg of a 77-year-old male that had rapidly grown in the last few months, the content of nuclear DNA in basaloid and clear cells was determined by cytofluorometry. The DNA content in the normal lymphocyte was assigned to 2C and the DNA histogram of the basaloid cells showed an aneuploidy pattern, with their average DNA content being 10.3C. The DNA histogram of the clear cells had a polyploidy pattern, with their average DNA content being 4.2C. Basaloid cells showed an abnormality severer than that of clear cells on the nuclear pattern as well as on the histological findings. A follicular structure is basically maintained in this tumor. The basaloid cells originated from a basal cell of a hair follicle with a natural ability to divide. The difference in the nuclear DNA content between the basaloid cells and clear cells may have thus accounted for the differential cell dividing ability between the cells.
