Both living and non-living things are composed of molecules made from chemical elements such as Carbon, Hydrogen, Oxygen, and Nitrogen. The organization of these molecules into cells is one feature that distinguishes living things from all other matter. The cell is the smallest unit of matter that can carry on all the processes of life .
The embryological origin of granulosa cells remains controversial. In the 1970s, evidence emerged that the first cells to make contact with the oogonia were of mesonephric origin. It was suggested that mesonephric cells already closely associated with the oogonia proliferated throughout development to form the granulosa cell layer.    Recently, this hypothesis has been challenged with some thorough histology . Sawyer et al. hypothesized that in sheep most of the granulosa cells develop from cells of the mesothelium (., epithelial cells from the presumptive surface epithelium of the ovary).  In 2013 it was proposed that both granulosa cells and the ovarian surface epithelial cells are instead derived from a precursor cell called Gonadal-Ridge Epithelial-like cell. 
A calretinin stain was performed in this case but was found to be negative. These tumours are usually positive for inhibin although it is not specific for this tumour. A recent study analysed ovarian sex-cord stromal tumours for calretinin positivity [ 7 ]. All the six steroid cell tumours in this study were positive for the marker. Calretinin can be considered a sensitive marker for ovarian sex-cord stromal tumours in general, but is less specific [ 8 ]. A similar study has evaluated the applicability of CD56 as a marker in ovarian sex-cord stromal tumours [ 9 ]. The authors concluded that it is a sensitive marker for these neoplasms, although it cannot help to differentiate a sex-cord stromal tumour from a neuroendocrine neoplasm. A number of immunohistochemical markers were reviewed for their utility in differential diagnosis of sex-cord stromal tumours and inhibin and calretinin were found to be most useful, among others, in differentiating sex-cord stromal from nonsex-cord stromal tumours, while MART-1 was diagnostically useful for steroid cell tumours [ 10 ].