Primary adrenal pleomorphic spindle cell sarcoma (PSCS) is an exceedingly rare mesenchymal tumour that was previously known as malignant fibrous histiocytoma. It commonly occurs in extremities, retroperitoneum, peritoneal cavity and rarely in visceral organs. We report the first case of PSCS in the left adrenal gland in a 65-year-old female who presented with a large abdominal mass with vague symptoms. The wide range of differential diagnoses posed a challenge in establishing the diagnosis. However, this was overcome by appropriate radiological, intra-operative, histological and most importantly, comprehensive immunohistochemical findings. The patient underwent complete surgical resection of the tumour and had an unremarkable recovery. She remains without metastasis or recurrences to date through her 18 months of post-operative follow-up despite the poor prognosis of this tumour.