Intra-abdominal desmoplastic small cell tumour in a patient with Peutz-Jeghers syndrome

A surgical case of intra-abdominal desmoplastic small cell tumour with divergent differentiation (IDS-CT) in a patient with Peutz-Jeghers syndrome (PJS) is reported. The patient was a 23-year-old woman who underwent surgery for a tumour in the left paraovarian region. Widespread peritoneal metastases were noted. Histopathological examination revealed solid cell nests composed of medium-sized cells demarcated by desmoplastic stroma. Gland-like spaces were found within many cell nests. Tumour cells were positive for cytokeratin and smooth muscle actin, but negative for desmin. Both ovaries contained minute foci of a sex cord tumour with annular tubules. This is the first documentation of the association of IDSCT with PJS. Since patients with PJS have an increased risk of cancer in various organs, the occurrence of IDSCT in the present patient might not be fortuitous.