Hana Kawatu¹, Maya Latimer^2,3, Mitali Fadia^1,3

¹Department of Anatomical Pathology, ACT Pathology, Canberra Health Services, Garran, ACT, Australia
²Department of Haematology, Canberra Health Services, Garran, ACT, Australia
³School of Medicine and Psychology, Australian National University, Canberra, ACT, Australia

We present a case of a 28-year-old female who delivered a live baby at 38 weeks gestation with a primary diagnosis of high-grade B cell lymphoma on placenta. The placenta was heavy and showed multifocal, pale lesions ranging from 2 mm to 5 mm across. On histology, the villi were diffusely filled by the discohesive population of monomorphic medium-sized lymphoid cells with minimal spill into the intervillous space. There was a significant amount of apoptosis with a starry-sky appearance. The neoplastic cells showed diffuse and strong positive staining for CD20, CD79a, PAX5, Bcl2 and cMyc, but negative for CD10. The FISH performed on the paraffin block showed t(8:14) (MYC/IGH) dual fusion. 

 

The baby was born with multifocal skin lesions, which showed similar morphology and immunophenotype like placenta. Short tandem repeat profiling showed chimerism of the cancer cells of maternal origin rather than foetal origin. 

 

Five months post-delivery, the asymptomatic mother was investigated, which revealed a PET AVID gastric lesion diagnosed as lymphoma. Following chemotherapy, the patient has been in remission for 5 years. 

 

This case demonstrates a unique primary involvement of lymphoma in the placenta with subsequent foetal transmission. The story begins with a placenta, where its findings save the mother’s life.