To the authorsʼ knowledge there is only one report in the literature, dealing with paramedullary plasmacytomas in horses as so-called “break out lesions”, originating from the bone marrow of a vertebra and invading the epidural space (Drew and Greatorex 1974). Our case report describes the clinical and patho-morphological findings of such a case. The affected 8-month-old warmblood weanling colt exhibited acute tetraparesis thus, a spinal cord lesion in the cervical column was suspected. Computed tomography revealed osteolytic lesions in C1 and a heterogeneous mass within the respective segment of the vertebral canal. By means of patho-morphological examination, with the aid of transmission electron microscopy, a plasmacytoma was identified, that had grown out of the bone marrow of C1 into the epidural space, locally compressing the spinal cord. In tetraparetic, young horses traumatic spine cord injuries, cervical vertebral malformations and infectious diseases of the central nervous system represent common differentials. However bone-dissolving tumours such as paramedullary plasmacytomas should be considered as a further possible cause in the presence of severe neurological deficits.

Granulosa cell tumour (GCT) is a benign tumour that affects a mare’s ovaries. In this report, a case of unilateral GCT in an ovary, which weighed 24 kg, of a 7-year-old warmblood mare is described, including ultrasonographic, clinical appearance and successful surgical removal of the tumour. The GCT was the cause of an acute hemoperitoneum and after a first stabilization of the mare, the GCT was removed through a ventral midline incision. Because of the enormous dimensions of the GCT, intra-abdominal partial resection of the tumor using a tenotomy knife was performed to exteriorize the ovarian pedicle. The technique can cause an intra-abdominal hemorrhage and the time between GCT resection and sealing of the respective ovarian pedicle should be as short as possible. After 3.5 months, the mare had a good cosmetic and functional outcome and was ridden for her intended use. Metastasis of GCT is rare, but not impossible. The mare therefore should be followed up for a longer period of time to investigate if metastasis develops.