Hybrid odontogenic lesions; a case series

Abstract

sampled for cytology. Results: Examination of the ovarian mass showed a high grade malignancy consistent with embryonal rhabdomyosarcoma. This was adjacent to, but separate from, a mature cystic teratoma. The tumour showed architecture ranging from alveolar, to diffuse with spindled cells, as well as focal cross striations. The tumour was positive for skeletal muscle markers, and negative for a wide panel of other stains including cytokeratins and germ cell markers. Molecular analysis showed no evidence of FOX01 rearrangement; DICER1 studies are pending. Peritoneal biopsies and cytology were benign. Conclusion: Given the absence of a primary tumour on imaging studies, metastatic rhabdomyosarcoma to the ovary is considered unlikely. Potential aetiologies in this case include rhabdomyosarcoma arising as a somatic malignancy ex mature teratoma, and rhabdomyosarcoma arising secondary to a somatic or germline DICER1 mutation. We present a review of the literature regarding these scenarios, and the limited available data regarding clinical outcomes for adult patients.