Aims: To describe the clinicopathological and immunohistochemical findings in 4 cases of uterine tumour resembling ovarian sex cord tumour (UTROSCT).
Methods: Four UTROSCTs in patients aged 43, 51, 73 and 84 were stained with a wide range of antibodies, including epithelial (AE1/3, epithelial membrane antigen), myoid (desmin, á smooth muscle actin, h-caldesmon), sex cord (á inhibin, calretinin, melan A, CD99) and neuroendocrine (chromogranin, CD56) markers as well as hormone receptors (oestrogen receptor, progesterone receptor, androgen receptor), vimentin, CD10, WT1 and HMB45.
Results: The tumours ranged from 0.8 to 19.5 cm. Three were relatively well circumscribed intramural myometrial lesions and the other a pedunculated mass attached to the uterine serosa. The tumours were variably composed of solid, corded, trabecular , nested, glandular and retiform arrangements of tumour cells. In 3 cases, cells with eccentric nuclei and abundant eosinophilic cytoplasm, resulting in a rhabdoid appearance, were a prominent feature. Three of 4 cases were diffusely positive with AE1/3 and all with epithelial membrane antigen. Positivity with myoid markers was common with 3, 4 and 1 case respectively staining with desmin, á smooth muscle actin and h-caldesmon. Two, 4, 1 and 2 cases respectively were positive with á inhibin, calretinin, melan A and CD99. All were chromogranin negative and exhibited diffuse strong staining with CD56. All were diffusely positive with oestrogen receptor, progesterone receptor, vimentin and WT1. Three cases were androgen receptor positive and all were CD10 and HMB45 negative.
Conclusions: UTROSCT exhibits a polyphenotypic immunophenotype with coexpression of markers of epithelial, myoid and sex cord lineage as well as hormone receptors. CD56 positivity has not been described previously and is further evidence of true sex cord differentiation since it has recently been shown that ovarian sex cord-stromal tumours are positive with this marker. However, epithelial membrane antigen positivity is against a true sex cord tumour. The polyphenotypic immunophenotype may be useful in diagnosis and in the exclusion of other neoplasms. UTROSCT is likely to be derived from an uncommitted cell with the capacity for multidirectional differentiation.
- SEX CORD TUMOUR